Original Article
Leber hereditary optic neuropathy in Australia David A Mackey, MB BS* Robert G Buttery, MB BS, P h D t
Abstract Leber hereditary optic neuropathy (LHON) presents with sudden onset of visual loss mainly in young adult males. LHON is not uncommon in Australia, accounting for 2% of invalid blind pensions. We have identified 20 unrelated families carrying mitochondrial DNA mutations associated with LHON and 135 of 291 individuals with documented LHON are currently alive in Australia. The mean age of onset of visual loss for males was 26 years and for females 27 years, with a range from six to 65 years. The mean risk of visual loss was 20% for males and 4% for females. There are over 1750 male and female carriers living in Australia who have not yet lost vision; 600 carriers are under 24 years of age. The expected number of new cases of blindness from LHON is three to four per year. Key words: Blindness, Leber hereditary optic neuro-' pathy, mitochondrial DNA mutations, visual loss.
Based upon the current population, there is no evidence that Leber hereditary optic neuropathy (LHON) was present in the Australian Aborigines when Australia was first settled by Europeans in 1788, nor were there any carriers in the first, second or third fleet to New South Wales. However, by the time Beer' first described the acute optic atrophy in 1817 there were already two separate families established in Australia. This had jumped to 13 separate families by 1871 when Leber' *Departmentof Ophthalmologyand The Murdoch Institute, Royd Children's Hospital, Melbourne. TRoyal Victorian Eye and Ear Hospital, Melbourne.
described the condition which now bears his name. Over 280 Australians had lost vision from LHON by the time Douglas C W a l l a ~ e ,an ~ American molecular geneticist, reported the most commonly found mitochondrial DNA mutation (11778 G- > A ND4 A340H) associated with the disease. Eight Australian families with LHON have been described in earlier publications. The first report by Pookley in 1915 describes two cousins from a New South Wales family (NSW1).4 A Western Australian family (WA1) was described in part by MorletY5 R o g e r ~Carroll ,~ and Mastaglia8who all gave clinical and investigative information. A Tasmanian family (Tasl) was described in part clinically by Hogg,'-" Belly6and Hamilton,12 with molecular genetic descriptions excluding X-linkage by Chen et a l l 3 and Newman et a l l 4 Another Tasmanian family (Tas2) was described in part by Hamilton." A third Tasmanian family (Tas3) was mentioned by Chen et a l l 3 and Howell et a1.l' in their molecular genetics papers. A Queensland family (Qldl) was first described by an Australian clinical geneticist, David C. W a l l a ~ e , ' ~ .and '~ further molecular genetics papers were written by Parker et ~ 1 . and ' ~ Howell et U ~ . ' ' . ~ O McLeod et a1.21.22 described a New South Wales family (NSW1) with Charcot-Marie-Tooth disease and LHON. A member of another New South Wales family (NSW2) had reduced rhodanese levels measured by Goadsby and Fine.'3 Finally the molecular genetics of a Victorian family (Vicl) was described by Howell et a l l 5 SturmanZ4described a New Zealand family of Norwegian origin. There do not appear to be any members of this family in Australia. There are, however, branches of some Australian families living in New Zealand. There are also some
Reprint reguestst Dr David Mackey, Department of Ophthalmology, Royal Children's Hospital, Flemington Road, Melbourne, Victoria 3052, Australia. Leber hereditary optic neuropathy in Australia
177
TEST TIE m:17:a
HA S/N 630-1815
Figure 1 Right eye threshold 30-2 Humphrey field (Allergan Humphrey, San Leandro CA) in a male patient with visual acuity 2/60 (atrophic stage Leber hereditary optic neuropathy).
unaffected members of one Finnish family in Australia (Nikoskelainen, personal communication) and some unaffected members of one Scottish family in Australia (Vic6) (Bronte-Stewart, personal communication). LHON classically presents as visual loss in otherwise healthy males aged between 18 and 30 years. The diagnosis is easily made when rapid visual loss below 6/60 occurs in one eye (followed within weeks by the second eye) with a maternal family history of similar visual loss. Centrocecal scotomas (Figure 1) with ophthalmoscopic features of disc oedema, tortuosity of the large vessels and peripapillary telangiectasia (Figure 2a, 2bY5-*' which do not leak fluorescein help confirm the diagnosis. Within months the disc is atrophic and the abnormal vessels have vanished (Figure 2c, 2d). ECG conduction abnormalities are found in some individual^.'^^^^^^^ Brainstem auditory evoked potentials are reported to be abnormal in some patients.30 In isolated cases the diagnosis of LHON is frequently m i ~ s e d . ~ , ' ~
Aim The aim of the present study was to identify all individuals in Australia with LHON, establish their ancestry and locate all relatives carrying the genes for LHON. This would provide an accurate measure of the prevalence of LHON and the number of people at risk for subsequent loss of vision. The study would also provide accurate 178
pedigree information for reference in cases of undiagnosed optic atrophy or optic neuropathy, allowing accurate diagnosis of LHON.
Method We contacted all the Australian organisations for the blind, who searched for any patients having optic atrophy. All available previous studies on LHON were obtained and contact was made with individuals in each family. Individuals were invited to contact our study group to give information on their family tree. The female line ancestry for each individual was traced using personal family knowledge, genealogical records (including Registrars General's records of birth, death, and marriage, probate records, land title records, Australian archives, church records and gravestone records) as well as old blind registries and medical records from doctors and hospitals. Families were linked back to single matriarch ancestors who arrived in Australia. They in turn were then followed as far back as possible using English, Irish and Scottish Church records. Once the matriarchs were established every child of the female line was found using birth, death and marriage records. The complete issue of a woman is usually given on her death certificate. This gave us a complete record of the female line descendants. Living individuals in these groups were then contacted to find out if there was any visual problem in the family. Individuals with loss of vision were interviewed and their records examined when Australian and New Zealand Journal of Ophthalmology 1992; ZO(3)
,
Figure 2 Optic nerve photographs in a 22-year-old male patient: (a, b) two weeks after visual loss noted in left eye; and (c, months later, when both eyes had acuities of 2/60.
possible. From this group, selected individuals, both blind and unaffected, were examined by the first author DAM. Blindness was defined as visual acuity at some stage less than 6/60 without other known cause. Data from previous studies and blind pension records were used to ascertain visual status in family members last century. All direct female line relatives are usually carriers of the same mitochondrial DNA mutation. However, if the mutation occurred recently some distant female line relatives may not carry the risk of developing LHON. Thus we also calculated the number of individuals and generations where the mutation could definitely be shown to exist based on clinical and molecular mtDNA evidence. From data on the age of all the carriers in the pedigrees and people with loss of vision we calculated the percentage of adults suffering blindness in each family. We used 24 years as the cutoff age Leber hereditary optic neuropathy in Australia
d)three
for counting an individual, just above the mean age of loss of vision given by All who lost vision before 24 years of age were included in the calculation. DNA studies were used to verify the diagnosis of LHON and will be published separately.
Results Twenty unrelated families were identified. Only one medium-sized pedigree is shown because of limited space (Figure 3). With the exception of one small New South Wales family and the non-affected members of one of Nikoskelainen’s families every patient could be located. Some 291 people had visual loss consistent with LHON. The ancestries of all families were traced to their arrival in Australia and are presented in Table 1. The number of generations and individuals is given with a grand total of 3537 identified female line 179
Figure 3 Pedigree of previously unpublished Qld2 showing only female line descendants. All individuals on the pedigree are probably carriers. Squares are male and circles female, while solid are those with visual loss.
descendants. The number of proven carrier generations and individuals is also given. Each family was labelled according to the state in which the most family members resided. The number of living family members, affected individuals and risk of visual loss are given in Table 2. The family prevalence of blindness in adult males varies from 7% to 58% while in females it varies from 0% to 15%. Ranges are stated within families where there is uncertainty of the exact age of some family
members. The overall mean risk of vision loss was 20% for adult males and 4% for adult females. The Department of Social Security gives the number of invalid blind pensions in June 1989 as 3972 males and 281 1 females (personal communication). Unfortunately, there is no reliable data on the medical diagnoses of patients receiving these pensions. Using the total number of visually impaired individuals with LHON we calculate that LHON accounts for 10413972 (2.6%) of male and
Table 1. Australian families with LHON Arrival in Australia
Generations traced*
Total female line descendants*
Total blind
1814 1843 1842 1842 1832 1913 1860s
12 (10) 12 (12) 9 (5) 7 (3) 9 (2) 7 (6) 7 (5)
1598 (1584) 659 (659) 83 (52) 64 (24) 63 (4) 70 (68) 64 (53)
8 (7) 8 (6)
NSW Vic, NSW Vic Vic Vic, WA Vic Vic, Scot
1850s 1849 1853 1850s 1810 1945 1853 1836 1925 1970s
7 (6) 8 (6) 8 (5) 5 (4) 8 (4) 9 (8) 6 (5) 5 (5)
Vic7
Vic, RSA
1980s
5 (4)
Vic8 Fin Jotal
Vic, Afgh
1989
4 (2)
134 (133) 124 (112) 205 (111) 46 (36) 40 (20) 10 (9) 78 (35) 103 (96) 32 (22) 35 (35) (Scot 8) 87 (86) (RSA 12) 42 (6)
107 58 1 1 1 40 7 1 29 12 11 2 6 5 5 3 1
?
?
?
Family
Location
Tas 1 Tas2 Tas3 Tas4 Tas5 Qldl Qld2 Adopted? WA 1 NSWl NSW2 NSW3 Vic 1 Vic2 Vic3 Vic4 Vic5 Vic6
Tas, Tas, Tas Tas Tas, Qld, Qld,
NSW, Vic NSW Vic, ACT NSW NSW
WA, Qld NSW
Nsw
20
3537
0
0
1 0 291
Afgh = Afghanistan, Fin =Finland, RSA = Republic of South Africa, Scot = Scotland. *The numbers in brackets refer to the minimal number that can at present be proven to carry a mitochondria1 DNA mutation. ?Adopted refers to an adopted boy who came from either Qld2 or WA1.
180
Australian and New Zealand Journal of Ophthalmology 1992; 20(3)
Table 2. Living family members in Australia with risk of vision loss ~~
Family Tasl Tad Tas3 Tas4 Tas5 Qldl Qld2 Adopted WAl NSWl NSW2 NSW3 Vic 1 Vic2 Vic3 Vic4 vic5 Vic6 Vic7 Vic8 Fin Total
Living blind
rn
f
36 16 1 0 1 12 6 1 10 2 3 1 3 2 5 3 1 0 0 1 0 104
7 4 0 1 0 10 1
2 0 1 0 2 3 0 0 0 0 0 0 0 31
Living female line relatives 914 396 36 29 9 39 50 1 71 47 134 37 15 8 43 57 19 3 (Aust) 4 (Aust) 5 (Aust) ?
1917
Family risk*
Children at risk
m
f
m
f
15-2070 19-22%
3 70 3%
? ? ?
? ? ?
149-163 56-58 3 4 1
? 10090 33-4370
60% 4-5%
160-179 55-56 8 1 2 4 8
47-5870 15-2770 10-12%
11-1370 7-1170 4%
10-11 1-4 21-22
9-10 2-9 21
?
?
12-1570 50% 07 0 0%
? 3 0 10 5 3 2
?
25-5070 66% 19-2670 7-9% ?
?
33% 32%
12% 070
?
? ? 4%
? 17-2270
11
12
1 1 4 8 2 0 2 2
1
2
~~
?
?
296-321
288-312
~
~~
*Ranges due to uncertainty of age of death and age of chiidren in family. Aust refers to number of family members in Australia. Risk in these (Aust) families has been calculated from the number of family members affected overseas.
31/2811 (1.170) of female (2.0% overall) blind pensions. The age of onset of loss of vision was obtained in 123 male subjects (mean standard deviation) 26.0-t 11.5 years and in 28 female subjects 27.2k12.5 years (range six to 65 years). The median age of loss of vision is slightly lower in males (23 years) than females (25 years). The number of people estimated to lose vision was calculated for each family based on previous rates of visual loss. A group estimate was obtained for all families. Both methods estimate that three to four people will lose vision from LHON every year in Australia. There were also some individuals who clinically had LHOB but had no known family history. Two families involved a single generation of affected brothers suggesting an autosomal recessive inheritance. There were five females and three males with unexplained visual loss. Another female had diabetes mellitus and an acute visual loss suggesting LHON. One male lost vision gradually, presumably from malnutrition while a prisoner of war in Changi prison during World War 11. These may represent isolated individuals with as yet unidentified mitochondria1 DNA mutations. Three families of autosomal dominant optic atrophy were also found. Leber hereditary optic neuropathy in Australia
Discussion LHON accounts for 2.6% of male, 1.1% of female and 2.0% overall of invalid blind pensions. This corresponds to the figures3’ for new blind pensions granted in Queensland over seven years from 1975-82. LHON accounted for 2.0% (9.8% of the 20.3% of hereditary causes) of blindness. The predicted number of children to lose vision based on each family’s relative risk is three to four per year in Australia. Thus LHON is not an uncommon cause of legal blindness in Australia. The ratio of affected fema1es:males for all 20 families is 1:5 (23.0%). However, when the Qldl family, with a very high rate of visual loss and other neurological problem^,'^." is excluded 18.6% are female. This corresponds closely with Newman’s figure of 18.1%,14 is a little higher than Bell’s figure for Europeans of 15.2’30, but much lower than her Japanese figures of 40.970.~ We found many more unaffected male and female ‘carriers’ (female line relatives) than expected from the number of blind individuals. This was because some families showed a very reduced risk of expression of optic neuropathy. The adult male risk of visual loss was only 7% in Vic4, while the overall risk of 17% to 22% is lower than the 50% quoted in the literature. There are several explanations for 181
this variable risk of visual loss. 1. The classic risk of 50% may be an overcalculation from ascertainment bias with every other study starting by counting families only when there is already an affected member. Often distant unaffected relatives are not counted but distant affected relatives are. 2. There may be mitochondria1 genetic heteroplasmy3* in a family with only the affected branches having sufficient mutant mitochondria. 3. Environmental factors may be involved, especially when we consider that the families with a high risk of manifesting the disease live in Qld and WA while the families with a lower risk of blindness live in NSW, Vic and Tas. 4. Incomplete identification of blind individuals is unlikely as the risk seems even lower if we count only living family members. Julia Bell6 quotes the mean age of loss of vision as 23 years. Nancy NewmanI4 gives a slightly higher figure of 27.6 years. The age of loss of vision obtained in our 123 male subjects was 26.0f 11.5 years and in 28 female subjects 27.2 f 12.5 years. The range of ages was from six to 65 years (Figure 4). The median ages for loss of vision are slightly lower with males at 23 years and females at 25 years and this same skew can be seen in Newrnan’~,’~ Lund~gaard’s~~ and Bell’s6 figures (Figure 5). This supports our use of 24 years as the cutoff age in estimating adult risk. However, the results are almost identical if a younger 18 years or an older 32 years cutoff range is used (18 to 32 years being the interquartile range). When considering the need for laboratory DNA testing two factors must be considered. 1. The genes AUSTRALIAN LHON AGE AT PRESENTATION NUMBER
30 I =MALES
=FEMALES
25 20
1,
~
MALE COMPARISON AGE AT PRESENTATION PERCENT
30% 25% 20% 15%
10% 5% 0%
0-3
8-11
18-19 24-27 32-35 40-43 48-51 56-59 64-67
AGE RANGE
Figure 5 Comparison of age of onset of visual loss from this study with those of N e ~ m a n and ’~
for LHON put a person at risk of visual loss. Thus a positive result does not mean that a person will go blind. 2. The transmission of the gene follows a strict maternal pattern and thus all relatives carrying the mutation can be ascertained from an accurate family tree. In large established families it is only necessary to test one or two members. Thus accurate genealogical work replaces the need for expensive laboratory testing of many individuals. If, however, the family tree is large with only one affected member, suggesting the possibility of a recent mutation, then wider genetic testing of the family is advisable. LHON is not easily diagnosed without a family history, so the establishment of accurate pedigree information allows easy reference to individuals with optic atrophy of undetermined aetiology. Although recent attention has focused on the molecular genetic aspects in diagnosis, the keystone to accurate diagnosis is an extended family history. The risk of visual loss varies from family to family, thus in providing adequate counselling a good family history is necessary. The explanation for this variable risk of visual loss remains to be determined as does the reason females are less affected than males.
15 (0
~
5
0 0-3
8-11
EI 24:27 32l35 40143 48:5l AGE RANGE
56:59
64-67
Figure 4 Graph showing the age of onset of visual loss for males and females. 182
Conclusion LHON is not uncommon in Australia. There are 20 families, some quite large, with the condition. Although the mean age of onset and ratio of males to females is similar to that quoted in the literature the overall risk of visual loss in Australian families is much lower than reported overseas. Further work needs to be done to explain this. Hopefully, Australian and New Zealand Journal of Ophthalmology 1992; ZO(3)
environmental or genetic trigger factors will be identified to enable effective preventive treatment. Acknowledgements Mrs Maree Ring (Genealogical Society of Tasmania) who extracted the genealogical records used to compile and verify the pedigrees. OPSM Research and Charitable Foundation for providing generous funding for the genealogical research. The Tasmanian Lions Eye Diagnostic Centre for assistance with funding and clinical facilities. T h e Royal Guide Dogs For T h e Blind Associations and affiliated organisations, The Royal Blind Society of NSW, The Royal Victorian Institute for the Blind, David Grey, Patsy Turner, Don Verlander, Ron Anderson, John Mostel, Janet Milligan, Shane Rollidge, Kerry Fitzmaurice, Linda McKenzie, Faye Brooks-Johnson, Jean Panton, Peg McCormack, Ian Cox, D r Michael Denton, D r Gordon Wise, D r Hector McLean, D r John King, Dr John Rogers, Dr Frank Mastaglia, Dr Ron Fine, Dr James Mcleod, Dr Isla Williams, Dr Pam Dickenson, D r Jennifer Bond, D r Bruce Gerrard, Dr Joan Bronte-Stewart, Dr John O’Neill, Dr Bruce Kerr, and D r C. Gregory Keith for assistance in establishing pedigrees. Dr Nicholas Downie, Dr Erwin Groeneveld, Dr Bernard OLeary, Professor Frank Billson and Dr Elizabeth Moller for providing facilities to examine patients. Teresa Woolley for assistance contacting patients. M r Kevin Bell for clinical photographs. Dr David Mackey was in receipt of a Royal Children’s Hospital (Melbourne) clinical research fellowship. This research was done under the supervision of the R C H research and ethics committee. References 1. Beer GJ: Lehre von den Augenkrankheiten. Wein, 1817;2: 2. Leber T . Ueber hereditare und congenital-angelegteSehnervenleiden. Graefe’s Arch Ophthalmol 1871;2:249-91. 3. Wallace DC, Singh G, Lott MT, Hodge JA, Schurr TG, Lezza AM, et al. Mitochondria1 DNA mutation associated with Leber’s hereditary optic neuropathy. Science 1988;242:1427-30. 4. Pookley E. Leber’s disease (hereditary optic atrophy). Med J Aust 1915;1:189-91. 5. Morlet C. Hereditary optic atrophy as a possible menace to the community. Med J Aust 1921;2(23):499-502. 6. Bell J. Hereditary optic atrophy (Leber’s disease). In Pearson K, ed. The Treasury of Human Inheritance. Cambridge: Cambridge At The University Press, 1931;325-423. 7. Rogers J. Leber’s disease. Aust J Ophthalmol 1977;5:111-19. 8. Carroll WM, Mastaglia FL. Leber’s optic neuropathy. A clinical and visual evoked potential study of affected and Leber hereditary optic neuropathy in Australia
asymptomatic members of a six generation family. Brain 1979; 102559-80. 9. Hogg GH. Hereditary optic atrophy. Med J Aust 1928;372-4. 10. Hogg GH. Hereditary optic nerve atrophy. E ENT Monthly 19287:193. 11. Hogg GH. Leber’s disease. Med J Aust 1915;1:253. 12. Hamilton JB. The significanceof heredity in ophthalmology. Preliminary survey of hereditary eye diseases in Tasmania. Br J Ophthalmol 1938;19-137. 13. Chen JD, Cox I, Denton MJ. Preliminary exclusion of an X-linked gene in Leber optic atrophy by linkage analysis. Hum Genet 1989;82:203-7. 14. Newman NJ, Lott MT, Wallace DC. The clinical characteristics of pedigrees of Leber’s hereditary optic neuropathy with the 11778 mutation. Am J Ophthalmol 1991;111:750-62. 15. Howell N, Bindoff L, McCullough DA, et al. Leber hereditary optic neuropathy: identification of the same mitochondria1 ND1 mutation in six pedigrees. Am J Hum Genet 1991;48:in press. 16. Wallace DC. A new manifestation of Leber’s disease and a new explanation for the agency responsible for its unusual pattern of inheritance. Brain 1970;93:121-32. 17. Wallace DC. Leber’s optic atrophy: a possible example of vertical transmission of a slow virus in man. Aust Ann Med 1970;3:259-62. 18. Parker WD Jr, Oley CA, Parks JK. A defect in mitochondrial electron-transport activity (NADH-coenzyme Q oxidoreductase) in Leber’s hereditary optic neuropathy. N Engl J Med 1989;320:1331-3. 19. Howell N, McCullough DA. An example of Leber hereditary optic neuropathy not involving a mutation in the mitochondrial ND4 gene. Am J Hum Genet 1990;47:629-34. 20. Howell N, Kubacka I, Xu M, McCullough DA. Leber hereditary optic neuropathy: involvement of the mitochondrial ND1 gene and evidence for an intragenic suppressor mutation. Am J Hum Genet 1991;48:935-42. 21. McLeod JG, Low PA, Morgan Hughes JA. A family with Charcot-Marie-Tooth disease and Leber’s optic atrophy. Proc Aust Assoc Neurol 1975;12:23-5. 22. McLeod JG, Low PA, Morgan Hughes JA. Charcot-MarieTooth disease with Leber optic atrophy. Neurology 1978;28: 179-84. 23. Goadsby PJ, Fine RD. Leber‘s optic atrophy and “rhodanese” activity. Letter. Med J Aust 1988;149:110-1. 24. Sturman D. Leber’s hereditary optic atrophy. Trans Ophthalmol SOCNZ 1984;36:66-8. 25. Smith JL, Hoyt WF, Susac JO. Ocular fundus in acute Leber optic neuropathy. Arch Ophthalmol 1973;90:349-354. 26. Nikoskelainen EK, Hoyt WF, Nummelin KU, Schatz H. Fundus findings in Leber’s hereditary optic neuroretinopathy. 111. Fluorescein angiographic studies. Arch Ophthalmol 1984;102:981-9. 27. Nikoskelainen E K , Hoyt WF, Nummelin K U . Ophthalmoscopic findings in Leber’s hereditary optic neuropathy. 11. The fundus findings in the affected family members. Arch Ophthalmol 1983;101:1059-68. 28. Rose FC, Bowden AN, Bowden PMA. The heart in Leber’s optic atrophy. Br J Ophthalmol 1970;54:388-93. 29. Nikoskelainen EK, Savontaus ML, Wanne OP, Katila MJ, Nummelin KU. Leber’s hereditary optic neuroretinopathy, a maternally inherited disease. A genealogic study in four pedigrees. Arch Ophthalmol 1987;105:665-71. 183
30. Mondelli M, Rossi A, Scarpini C, Dotti MT, Federico A. BAEP changes in Leber’s hereditary optic atrophy: further confirmation of multisystem involvement. Acta Neurol Scandinav 1990;81:349-53. 31. Yeates FM. Causes of binocular legal blindness in an Australian metropolitan community. Aust J Ophthalmol 1983;11:321-3.
32. Holt I], Miller DH, Harding AE. Genetic heterogeneity and mitochondria1 DNA heteroplasmy in Leber’s hereditary optic neuropathy. J Med Genet 1989;26:739-43. 33. Lundsgaard R. Leber’s disease. A genealogical, genetic and clinical study of 101 cases of retrobulbar optic neuritis in 20 Danish families (thesis). Acta Ophthalmol (Copenh) 1944;2 l,~~ppl:3-306.
VITREORETINAL FELLOWSHIP The Department of Ophthalmology at the Casey Eye Institute, Oregon Health Sciences University, Portland, Oregon is offering a 2-year vitreoretinal fellowship, beginning July 1, 1993. Training is offered in all modalities for the modern diagnosis and treatment of retinal and vitreal disease. This includes laser treatment with argon and dye lasers, fluorescein angiography and interpretation, vitrectomy surgery with Ocutome and Microvit equipment, pneumatic retinopexy and advanced vitreal surgery with preretinal membrane removal and with silicone injection, and intraocular SF6 and C3F8 gas exchange. Must be eligible for Oregon licensure. Please direct all inquiries to Joe Robertson, M.D., Casey Eye Institute/OHSU, 3375 S. W. Terwilliger Blvd, Portland OR 97201-4197, USA.
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104
Australian and New Zealand Journal of Ophthalmology 1992; ZO(3)
Leber hereditary optic neuropathy in Australia David A Mackey, MB BS* Robert G Buttery, MB BS, P h D t
Abstract Leber hereditary optic neuropathy (LHON) presents with sudden onset of visual loss mainly in young adult males. LHON is not uncommon in Australia, accounting for 2% of invalid blind pensions. We have identified 20 unrelated families carrying mitochondrial DNA mutations associated with LHON and 135 of 291 individuals with documented LHON are currently alive in Australia. The mean age of onset of visual loss for males was 26 years and for females 27 years, with a range from six to 65 years. The mean risk of visual loss was 20% for males and 4% for females. There are over 1750 male and female carriers living in Australia who have not yet lost vision; 600 carriers are under 24 years of age. The expected number of new cases of blindness from LHON is three to four per year. Key words: Blindness, Leber hereditary optic neuro-' pathy, mitochondrial DNA mutations, visual loss.
Based upon the current population, there is no evidence that Leber hereditary optic neuropathy (LHON) was present in the Australian Aborigines when Australia was first settled by Europeans in 1788, nor were there any carriers in the first, second or third fleet to New South Wales. However, by the time Beer' first described the acute optic atrophy in 1817 there were already two separate families established in Australia. This had jumped to 13 separate families by 1871 when Leber' *Departmentof Ophthalmologyand The Murdoch Institute, Royd Children's Hospital, Melbourne. TRoyal Victorian Eye and Ear Hospital, Melbourne.
described the condition which now bears his name. Over 280 Australians had lost vision from LHON by the time Douglas C W a l l a ~ e ,an ~ American molecular geneticist, reported the most commonly found mitochondrial DNA mutation (11778 G- > A ND4 A340H) associated with the disease. Eight Australian families with LHON have been described in earlier publications. The first report by Pookley in 1915 describes two cousins from a New South Wales family (NSW1).4 A Western Australian family (WA1) was described in part by MorletY5 R o g e r ~Carroll ,~ and Mastaglia8who all gave clinical and investigative information. A Tasmanian family (Tasl) was described in part clinically by Hogg,'-" Belly6and Hamilton,12 with molecular genetic descriptions excluding X-linkage by Chen et a l l 3 and Newman et a l l 4 Another Tasmanian family (Tas2) was described in part by Hamilton." A third Tasmanian family (Tas3) was mentioned by Chen et a l l 3 and Howell et a1.l' in their molecular genetics papers. A Queensland family (Qldl) was first described by an Australian clinical geneticist, David C. W a l l a ~ e , ' ~ .and '~ further molecular genetics papers were written by Parker et ~ 1 . and ' ~ Howell et U ~ . ' ' . ~ O McLeod et a1.21.22 described a New South Wales family (NSW1) with Charcot-Marie-Tooth disease and LHON. A member of another New South Wales family (NSW2) had reduced rhodanese levels measured by Goadsby and Fine.'3 Finally the molecular genetics of a Victorian family (Vicl) was described by Howell et a l l 5 SturmanZ4described a New Zealand family of Norwegian origin. There do not appear to be any members of this family in Australia. There are, however, branches of some Australian families living in New Zealand. There are also some
Reprint reguestst Dr David Mackey, Department of Ophthalmology, Royal Children's Hospital, Flemington Road, Melbourne, Victoria 3052, Australia. Leber hereditary optic neuropathy in Australia
177
TEST TIE m:17:a
HA S/N 630-1815
Figure 1 Right eye threshold 30-2 Humphrey field (Allergan Humphrey, San Leandro CA) in a male patient with visual acuity 2/60 (atrophic stage Leber hereditary optic neuropathy).
unaffected members of one Finnish family in Australia (Nikoskelainen, personal communication) and some unaffected members of one Scottish family in Australia (Vic6) (Bronte-Stewart, personal communication). LHON classically presents as visual loss in otherwise healthy males aged between 18 and 30 years. The diagnosis is easily made when rapid visual loss below 6/60 occurs in one eye (followed within weeks by the second eye) with a maternal family history of similar visual loss. Centrocecal scotomas (Figure 1) with ophthalmoscopic features of disc oedema, tortuosity of the large vessels and peripapillary telangiectasia (Figure 2a, 2bY5-*' which do not leak fluorescein help confirm the diagnosis. Within months the disc is atrophic and the abnormal vessels have vanished (Figure 2c, 2d). ECG conduction abnormalities are found in some individual^.'^^^^^^^ Brainstem auditory evoked potentials are reported to be abnormal in some patients.30 In isolated cases the diagnosis of LHON is frequently m i ~ s e d . ~ , ' ~
Aim The aim of the present study was to identify all individuals in Australia with LHON, establish their ancestry and locate all relatives carrying the genes for LHON. This would provide an accurate measure of the prevalence of LHON and the number of people at risk for subsequent loss of vision. The study would also provide accurate 178
pedigree information for reference in cases of undiagnosed optic atrophy or optic neuropathy, allowing accurate diagnosis of LHON.
Method We contacted all the Australian organisations for the blind, who searched for any patients having optic atrophy. All available previous studies on LHON were obtained and contact was made with individuals in each family. Individuals were invited to contact our study group to give information on their family tree. The female line ancestry for each individual was traced using personal family knowledge, genealogical records (including Registrars General's records of birth, death, and marriage, probate records, land title records, Australian archives, church records and gravestone records) as well as old blind registries and medical records from doctors and hospitals. Families were linked back to single matriarch ancestors who arrived in Australia. They in turn were then followed as far back as possible using English, Irish and Scottish Church records. Once the matriarchs were established every child of the female line was found using birth, death and marriage records. The complete issue of a woman is usually given on her death certificate. This gave us a complete record of the female line descendants. Living individuals in these groups were then contacted to find out if there was any visual problem in the family. Individuals with loss of vision were interviewed and their records examined when Australian and New Zealand Journal of Ophthalmology 1992; ZO(3)
,
Figure 2 Optic nerve photographs in a 22-year-old male patient: (a, b) two weeks after visual loss noted in left eye; and (c, months later, when both eyes had acuities of 2/60.
possible. From this group, selected individuals, both blind and unaffected, were examined by the first author DAM. Blindness was defined as visual acuity at some stage less than 6/60 without other known cause. Data from previous studies and blind pension records were used to ascertain visual status in family members last century. All direct female line relatives are usually carriers of the same mitochondrial DNA mutation. However, if the mutation occurred recently some distant female line relatives may not carry the risk of developing LHON. Thus we also calculated the number of individuals and generations where the mutation could definitely be shown to exist based on clinical and molecular mtDNA evidence. From data on the age of all the carriers in the pedigrees and people with loss of vision we calculated the percentage of adults suffering blindness in each family. We used 24 years as the cutoff age Leber hereditary optic neuropathy in Australia
d)three
for counting an individual, just above the mean age of loss of vision given by All who lost vision before 24 years of age were included in the calculation. DNA studies were used to verify the diagnosis of LHON and will be published separately.
Results Twenty unrelated families were identified. Only one medium-sized pedigree is shown because of limited space (Figure 3). With the exception of one small New South Wales family and the non-affected members of one of Nikoskelainen’s families every patient could be located. Some 291 people had visual loss consistent with LHON. The ancestries of all families were traced to their arrival in Australia and are presented in Table 1. The number of generations and individuals is given with a grand total of 3537 identified female line 179
Figure 3 Pedigree of previously unpublished Qld2 showing only female line descendants. All individuals on the pedigree are probably carriers. Squares are male and circles female, while solid are those with visual loss.
descendants. The number of proven carrier generations and individuals is also given. Each family was labelled according to the state in which the most family members resided. The number of living family members, affected individuals and risk of visual loss are given in Table 2. The family prevalence of blindness in adult males varies from 7% to 58% while in females it varies from 0% to 15%. Ranges are stated within families where there is uncertainty of the exact age of some family
members. The overall mean risk of vision loss was 20% for adult males and 4% for adult females. The Department of Social Security gives the number of invalid blind pensions in June 1989 as 3972 males and 281 1 females (personal communication). Unfortunately, there is no reliable data on the medical diagnoses of patients receiving these pensions. Using the total number of visually impaired individuals with LHON we calculate that LHON accounts for 10413972 (2.6%) of male and
Table 1. Australian families with LHON Arrival in Australia
Generations traced*
Total female line descendants*
Total blind
1814 1843 1842 1842 1832 1913 1860s
12 (10) 12 (12) 9 (5) 7 (3) 9 (2) 7 (6) 7 (5)
1598 (1584) 659 (659) 83 (52) 64 (24) 63 (4) 70 (68) 64 (53)
8 (7) 8 (6)
NSW Vic, NSW Vic Vic Vic, WA Vic Vic, Scot
1850s 1849 1853 1850s 1810 1945 1853 1836 1925 1970s
7 (6) 8 (6) 8 (5) 5 (4) 8 (4) 9 (8) 6 (5) 5 (5)
Vic7
Vic, RSA
1980s
5 (4)
Vic8 Fin Jotal
Vic, Afgh
1989
4 (2)
134 (133) 124 (112) 205 (111) 46 (36) 40 (20) 10 (9) 78 (35) 103 (96) 32 (22) 35 (35) (Scot 8) 87 (86) (RSA 12) 42 (6)
107 58 1 1 1 40 7 1 29 12 11 2 6 5 5 3 1
?
?
?
Family
Location
Tas 1 Tas2 Tas3 Tas4 Tas5 Qldl Qld2 Adopted? WA 1 NSWl NSW2 NSW3 Vic 1 Vic2 Vic3 Vic4 Vic5 Vic6
Tas, Tas, Tas Tas Tas, Qld, Qld,
NSW, Vic NSW Vic, ACT NSW NSW
WA, Qld NSW
Nsw
20
3537
0
0
1 0 291
Afgh = Afghanistan, Fin =Finland, RSA = Republic of South Africa, Scot = Scotland. *The numbers in brackets refer to the minimal number that can at present be proven to carry a mitochondria1 DNA mutation. ?Adopted refers to an adopted boy who came from either Qld2 or WA1.
180
Australian and New Zealand Journal of Ophthalmology 1992; 20(3)
Table 2. Living family members in Australia with risk of vision loss ~~
Family Tasl Tad Tas3 Tas4 Tas5 Qldl Qld2 Adopted WAl NSWl NSW2 NSW3 Vic 1 Vic2 Vic3 Vic4 vic5 Vic6 Vic7 Vic8 Fin Total
Living blind
rn
f
36 16 1 0 1 12 6 1 10 2 3 1 3 2 5 3 1 0 0 1 0 104
7 4 0 1 0 10 1
2 0 1 0 2 3 0 0 0 0 0 0 0 31
Living female line relatives 914 396 36 29 9 39 50 1 71 47 134 37 15 8 43 57 19 3 (Aust) 4 (Aust) 5 (Aust) ?
1917
Family risk*
Children at risk
m
f
m
f
15-2070 19-22%
3 70 3%
? ? ?
? ? ?
149-163 56-58 3 4 1
? 10090 33-4370
60% 4-5%
160-179 55-56 8 1 2 4 8
47-5870 15-2770 10-12%
11-1370 7-1170 4%
10-11 1-4 21-22
9-10 2-9 21
?
?
12-1570 50% 07 0 0%
? 3 0 10 5 3 2
?
25-5070 66% 19-2670 7-9% ?
?
33% 32%
12% 070
?
? ? 4%
? 17-2270
11
12
1 1 4 8 2 0 2 2
1
2
~~
?
?
296-321
288-312
~
~~
*Ranges due to uncertainty of age of death and age of chiidren in family. Aust refers to number of family members in Australia. Risk in these (Aust) families has been calculated from the number of family members affected overseas.
31/2811 (1.170) of female (2.0% overall) blind pensions. The age of onset of loss of vision was obtained in 123 male subjects (mean standard deviation) 26.0-t 11.5 years and in 28 female subjects 27.2k12.5 years (range six to 65 years). The median age of loss of vision is slightly lower in males (23 years) than females (25 years). The number of people estimated to lose vision was calculated for each family based on previous rates of visual loss. A group estimate was obtained for all families. Both methods estimate that three to four people will lose vision from LHON every year in Australia. There were also some individuals who clinically had LHOB but had no known family history. Two families involved a single generation of affected brothers suggesting an autosomal recessive inheritance. There were five females and three males with unexplained visual loss. Another female had diabetes mellitus and an acute visual loss suggesting LHON. One male lost vision gradually, presumably from malnutrition while a prisoner of war in Changi prison during World War 11. These may represent isolated individuals with as yet unidentified mitochondria1 DNA mutations. Three families of autosomal dominant optic atrophy were also found. Leber hereditary optic neuropathy in Australia
Discussion LHON accounts for 2.6% of male, 1.1% of female and 2.0% overall of invalid blind pensions. This corresponds to the figures3’ for new blind pensions granted in Queensland over seven years from 1975-82. LHON accounted for 2.0% (9.8% of the 20.3% of hereditary causes) of blindness. The predicted number of children to lose vision based on each family’s relative risk is three to four per year in Australia. Thus LHON is not an uncommon cause of legal blindness in Australia. The ratio of affected fema1es:males for all 20 families is 1:5 (23.0%). However, when the Qldl family, with a very high rate of visual loss and other neurological problem^,'^." is excluded 18.6% are female. This corresponds closely with Newman’s figure of 18.1%,14 is a little higher than Bell’s figure for Europeans of 15.2’30, but much lower than her Japanese figures of 40.970.~ We found many more unaffected male and female ‘carriers’ (female line relatives) than expected from the number of blind individuals. This was because some families showed a very reduced risk of expression of optic neuropathy. The adult male risk of visual loss was only 7% in Vic4, while the overall risk of 17% to 22% is lower than the 50% quoted in the literature. There are several explanations for 181
this variable risk of visual loss. 1. The classic risk of 50% may be an overcalculation from ascertainment bias with every other study starting by counting families only when there is already an affected member. Often distant unaffected relatives are not counted but distant affected relatives are. 2. There may be mitochondria1 genetic heteroplasmy3* in a family with only the affected branches having sufficient mutant mitochondria. 3. Environmental factors may be involved, especially when we consider that the families with a high risk of manifesting the disease live in Qld and WA while the families with a lower risk of blindness live in NSW, Vic and Tas. 4. Incomplete identification of blind individuals is unlikely as the risk seems even lower if we count only living family members. Julia Bell6 quotes the mean age of loss of vision as 23 years. Nancy NewmanI4 gives a slightly higher figure of 27.6 years. The age of loss of vision obtained in our 123 male subjects was 26.0f 11.5 years and in 28 female subjects 27.2 f 12.5 years. The range of ages was from six to 65 years (Figure 4). The median ages for loss of vision are slightly lower with males at 23 years and females at 25 years and this same skew can be seen in Newrnan’~,’~ Lund~gaard’s~~ and Bell’s6 figures (Figure 5). This supports our use of 24 years as the cutoff age in estimating adult risk. However, the results are almost identical if a younger 18 years or an older 32 years cutoff range is used (18 to 32 years being the interquartile range). When considering the need for laboratory DNA testing two factors must be considered. 1. The genes AUSTRALIAN LHON AGE AT PRESENTATION NUMBER
30 I =MALES
=FEMALES
25 20
1,
~
MALE COMPARISON AGE AT PRESENTATION PERCENT
30% 25% 20% 15%
10% 5% 0%
0-3
8-11
18-19 24-27 32-35 40-43 48-51 56-59 64-67
AGE RANGE
Figure 5 Comparison of age of onset of visual loss from this study with those of N e ~ m a n and ’~
for LHON put a person at risk of visual loss. Thus a positive result does not mean that a person will go blind. 2. The transmission of the gene follows a strict maternal pattern and thus all relatives carrying the mutation can be ascertained from an accurate family tree. In large established families it is only necessary to test one or two members. Thus accurate genealogical work replaces the need for expensive laboratory testing of many individuals. If, however, the family tree is large with only one affected member, suggesting the possibility of a recent mutation, then wider genetic testing of the family is advisable. LHON is not easily diagnosed without a family history, so the establishment of accurate pedigree information allows easy reference to individuals with optic atrophy of undetermined aetiology. Although recent attention has focused on the molecular genetic aspects in diagnosis, the keystone to accurate diagnosis is an extended family history. The risk of visual loss varies from family to family, thus in providing adequate counselling a good family history is necessary. The explanation for this variable risk of visual loss remains to be determined as does the reason females are less affected than males.
15 (0
~
5
0 0-3
8-11
EI 24:27 32l35 40143 48:5l AGE RANGE
56:59
64-67
Figure 4 Graph showing the age of onset of visual loss for males and females. 182
Conclusion LHON is not uncommon in Australia. There are 20 families, some quite large, with the condition. Although the mean age of onset and ratio of males to females is similar to that quoted in the literature the overall risk of visual loss in Australian families is much lower than reported overseas. Further work needs to be done to explain this. Hopefully, Australian and New Zealand Journal of Ophthalmology 1992; ZO(3)
environmental or genetic trigger factors will be identified to enable effective preventive treatment. Acknowledgements Mrs Maree Ring (Genealogical Society of Tasmania) who extracted the genealogical records used to compile and verify the pedigrees. OPSM Research and Charitable Foundation for providing generous funding for the genealogical research. The Tasmanian Lions Eye Diagnostic Centre for assistance with funding and clinical facilities. T h e Royal Guide Dogs For T h e Blind Associations and affiliated organisations, The Royal Blind Society of NSW, The Royal Victorian Institute for the Blind, David Grey, Patsy Turner, Don Verlander, Ron Anderson, John Mostel, Janet Milligan, Shane Rollidge, Kerry Fitzmaurice, Linda McKenzie, Faye Brooks-Johnson, Jean Panton, Peg McCormack, Ian Cox, D r Michael Denton, D r Gordon Wise, D r Hector McLean, D r John King, Dr John Rogers, Dr Frank Mastaglia, Dr Ron Fine, Dr James Mcleod, Dr Isla Williams, Dr Pam Dickenson, D r Jennifer Bond, D r Bruce Gerrard, Dr Joan Bronte-Stewart, Dr John O’Neill, Dr Bruce Kerr, and D r C. Gregory Keith for assistance in establishing pedigrees. Dr Nicholas Downie, Dr Erwin Groeneveld, Dr Bernard OLeary, Professor Frank Billson and Dr Elizabeth Moller for providing facilities to examine patients. Teresa Woolley for assistance contacting patients. M r Kevin Bell for clinical photographs. Dr David Mackey was in receipt of a Royal Children’s Hospital (Melbourne) clinical research fellowship. This research was done under the supervision of the R C H research and ethics committee. References 1. Beer GJ: Lehre von den Augenkrankheiten. Wein, 1817;2: 2. Leber T . Ueber hereditare und congenital-angelegteSehnervenleiden. Graefe’s Arch Ophthalmol 1871;2:249-91. 3. Wallace DC, Singh G, Lott MT, Hodge JA, Schurr TG, Lezza AM, et al. Mitochondria1 DNA mutation associated with Leber’s hereditary optic neuropathy. Science 1988;242:1427-30. 4. Pookley E. Leber’s disease (hereditary optic atrophy). Med J Aust 1915;1:189-91. 5. Morlet C. Hereditary optic atrophy as a possible menace to the community. Med J Aust 1921;2(23):499-502. 6. Bell J. Hereditary optic atrophy (Leber’s disease). In Pearson K, ed. The Treasury of Human Inheritance. Cambridge: Cambridge At The University Press, 1931;325-423. 7. Rogers J. Leber’s disease. Aust J Ophthalmol 1977;5:111-19. 8. Carroll WM, Mastaglia FL. Leber’s optic neuropathy. A clinical and visual evoked potential study of affected and Leber hereditary optic neuropathy in Australia
asymptomatic members of a six generation family. Brain 1979; 102559-80. 9. Hogg GH. Hereditary optic atrophy. Med J Aust 1928;372-4. 10. Hogg GH. Hereditary optic nerve atrophy. E ENT Monthly 19287:193. 11. Hogg GH. Leber’s disease. Med J Aust 1915;1:253. 12. Hamilton JB. The significanceof heredity in ophthalmology. Preliminary survey of hereditary eye diseases in Tasmania. Br J Ophthalmol 1938;19-137. 13. Chen JD, Cox I, Denton MJ. Preliminary exclusion of an X-linked gene in Leber optic atrophy by linkage analysis. Hum Genet 1989;82:203-7. 14. Newman NJ, Lott MT, Wallace DC. The clinical characteristics of pedigrees of Leber’s hereditary optic neuropathy with the 11778 mutation. Am J Ophthalmol 1991;111:750-62. 15. Howell N, Bindoff L, McCullough DA, et al. Leber hereditary optic neuropathy: identification of the same mitochondria1 ND1 mutation in six pedigrees. Am J Hum Genet 1991;48:in press. 16. Wallace DC. A new manifestation of Leber’s disease and a new explanation for the agency responsible for its unusual pattern of inheritance. Brain 1970;93:121-32. 17. Wallace DC. Leber’s optic atrophy: a possible example of vertical transmission of a slow virus in man. Aust Ann Med 1970;3:259-62. 18. Parker WD Jr, Oley CA, Parks JK. A defect in mitochondrial electron-transport activity (NADH-coenzyme Q oxidoreductase) in Leber’s hereditary optic neuropathy. N Engl J Med 1989;320:1331-3. 19. Howell N, McCullough DA. An example of Leber hereditary optic neuropathy not involving a mutation in the mitochondrial ND4 gene. Am J Hum Genet 1990;47:629-34. 20. Howell N, Kubacka I, Xu M, McCullough DA. Leber hereditary optic neuropathy: involvement of the mitochondrial ND1 gene and evidence for an intragenic suppressor mutation. Am J Hum Genet 1991;48:935-42. 21. McLeod JG, Low PA, Morgan Hughes JA. A family with Charcot-Marie-Tooth disease and Leber’s optic atrophy. Proc Aust Assoc Neurol 1975;12:23-5. 22. McLeod JG, Low PA, Morgan Hughes JA. Charcot-MarieTooth disease with Leber optic atrophy. Neurology 1978;28: 179-84. 23. Goadsby PJ, Fine RD. Leber‘s optic atrophy and “rhodanese” activity. Letter. Med J Aust 1988;149:110-1. 24. Sturman D. Leber’s hereditary optic atrophy. Trans Ophthalmol SOCNZ 1984;36:66-8. 25. Smith JL, Hoyt WF, Susac JO. Ocular fundus in acute Leber optic neuropathy. Arch Ophthalmol 1973;90:349-354. 26. Nikoskelainen EK, Hoyt WF, Nummelin KU, Schatz H. Fundus findings in Leber’s hereditary optic neuroretinopathy. 111. Fluorescein angiographic studies. Arch Ophthalmol 1984;102:981-9. 27. Nikoskelainen E K , Hoyt WF, Nummelin K U . Ophthalmoscopic findings in Leber’s hereditary optic neuropathy. 11. The fundus findings in the affected family members. Arch Ophthalmol 1983;101:1059-68. 28. Rose FC, Bowden AN, Bowden PMA. The heart in Leber’s optic atrophy. Br J Ophthalmol 1970;54:388-93. 29. Nikoskelainen EK, Savontaus ML, Wanne OP, Katila MJ, Nummelin KU. Leber’s hereditary optic neuroretinopathy, a maternally inherited disease. A genealogic study in four pedigrees. Arch Ophthalmol 1987;105:665-71. 183
30. Mondelli M, Rossi A, Scarpini C, Dotti MT, Federico A. BAEP changes in Leber’s hereditary optic atrophy: further confirmation of multisystem involvement. Acta Neurol Scandinav 1990;81:349-53. 31. Yeates FM. Causes of binocular legal blindness in an Australian metropolitan community. Aust J Ophthalmol 1983;11:321-3.
32. Holt I], Miller DH, Harding AE. Genetic heterogeneity and mitochondria1 DNA heteroplasmy in Leber’s hereditary optic neuropathy. J Med Genet 1989;26:739-43. 33. Lundsgaard R. Leber’s disease. A genealogical, genetic and clinical study of 101 cases of retrobulbar optic neuritis in 20 Danish families (thesis). Acta Ophthalmol (Copenh) 1944;2 l,~~ppl:3-306.
VITREORETINAL FELLOWSHIP The Department of Ophthalmology at the Casey Eye Institute, Oregon Health Sciences University, Portland, Oregon is offering a 2-year vitreoretinal fellowship, beginning July 1, 1993. Training is offered in all modalities for the modern diagnosis and treatment of retinal and vitreal disease. This includes laser treatment with argon and dye lasers, fluorescein angiography and interpretation, vitrectomy surgery with Ocutome and Microvit equipment, pneumatic retinopexy and advanced vitreal surgery with preretinal membrane removal and with silicone injection, and intraocular SF6 and C3F8 gas exchange. Must be eligible for Oregon licensure. Please direct all inquiries to Joe Robertson, M.D., Casey Eye Institute/OHSU, 3375 S. W. Terwilliger Blvd, Portland OR 97201-4197, USA.
We would prefer to receive applications by September 1, 1992. The deadline for the Ophthalmology Fellowship Match is Monday, November 16, 1992.
104
Australian and New Zealand Journal of Ophthalmology 1992; ZO(3)
