American Journal of Medical Genetics 42546-548 (1992)
Linkage Map of the Chromosomal Region Surrounding the Infantile Neuronal Ceroid Lipofuscinosis on l p Irma Jarvela, Pirkko Santavuori, Lea Puhakka, Matti Haltia, and Leena Peltonen Laboratory of Molecular Genetics, National Public Health Institute, Helsinki (I.J., L P . , L P . ) , Departments of Child Neurology (P.S.) and Pathology (M.H.), University of Helsinki, Helsinki, Finland The neuronal ceroid lipofuscinoses (NCLs) of childhood are divided into 3 main types according t o age-of-onset, clinical course, and neurophysiological and neuropathological findings: infantile, late infantile, and juvenile. All forms are inherited as a n autosomal recessive trait, and their biochemical background is still unknown. The infantile type (INCL) with the earliest age-of-onset a n d the most severe clinical course, occurs in Finland with an incidence of 1:20,000, i.e., 116patients have been found in our country up to now, whereas only about 50 cases have been reported from other parts of the world. Earlier we reported the linkage of INCL to the short a r m of chromosome 1. Here we describe a more precise linkage map of this area. Our current m a p places the INCL mutation between DlS57 and DlS79; D1S7 has so f a r shown no recombination events between the marker and the disease (lod score 4.55 at 0 = 0.00). Our material includes 64% of all living patients in Finland, and n o linkage disequilibrium of haplotypes is seen, using the 2 physically close markers DlS57 and DlS79. This finding as well as our LINKMAP analyses suggest that the distance between the disease locus and the flanking markers is about 3-4 cm.
KEY WORDS: NCL, chromosome 1, DNA diagnostics INTRODUCTION Neuronal ceroid lipofuscinosis (NCL) is a disease group characterized by progressive mental retardation, Received for publication April 5,1991; revision received July 15, 1991. Address reprint requests to Irma Jarvela, M.D., National Public Health Institute, Laboratory of Molecular Genetics, Mannerheimintie 166, 00300 Helsinki, Finland.
0 1992 Wiley-Liss, Inc.
blindness, ataxia, seizures, and accumulation of ceroidand lipofuscin-like storage cytosomes in various tissues due to unknown biochemical defect(s1. The childhood forms of the disease are divided into 3 different types: infantile (INCL, Santavuori-Haltia disease), late infantile (LINCL, Jansky-Bielschowsky disease, early onset Batten disease), and juvenile (JNCL, Spielmeyer-VogtSjogren, late onset Batten disease). All types are inherited as an autosomal recessive trait [Santavuori, 19881. The first signs of the most severe form, INCL, appear at age of 8-20 months. The main symptoms of this fatal disease are rapid psychomotor retardation, muscular hypotonia, ataxia, visual failure, myoclonic jerks, microcephaly, and knitting hyperkinesia (not in all patients). EEG approaches isoelectricity by age 3 years, and the mean age of death is about 10 years [Santavuori et al., 1974; Haltia, 19871. Linkage analyses have only recently established that INCL and JNCL are due to different mutations: The gene locus for JNCL has been mapped to chromosome 16 [Gardiner et al., 19901, whereas that of INCL has been localized to the short arm of chromosome 1 [Jokiaho et al., 1990; Jarvela et al., 19911by means of highly polymorphic VNTR (variable number of tandem repeat) markers [Nakamura et al., 19871. The gene locus of the third form, LINCL is still to be determined. MATERIALS AND METHODS Family Material The DNA samples of 20 Finnish INCL families were included in this study. These samples represent 64% of the living patients and their families in this country. In 5 INCL families there were 2 affected children, whereas in 15 families there was only one affected child. Twentysix healthy siblings were included in our materials (Table I). All patients were seen by one of the authors (P.S.), and the diagnosis was based on criteria summarized in Table 11: clinical course, neurophysiological, and ophthalmological findings and the electron microscopic changes of a rectal biopsy sample or of various tissues at autopsy in deceased children. Because INCL is a rare recessive disorder with the unique clinical picture enriched in a small isolated population, no heterogeneity was suspected.
Linkage Map of INCL TABLE I. INCL Families Studied
Fam 1 Fam 2 Fam 3 Fam 4 Fam 5 Fam 6-20
No. of affected children 2 2 2 2 2 1
547
The probes were radiolabeled with multiprime extension to a specific activity of 1-2 x lo9 cpndkg. Autoradiography was carried out on Kodak X-Omat films with intensifying screens for 4-7 days at - 80°C. Linkage analyses were carried out by the LINKAGE package computer program version, 5.03 [Lathrop et al., 19841, updated by Dr. Jurg Ott.
No. of unaffected children
0 1 1 1 1 22
TABLE 11. Clinical Characteristics of INCL Symptoms and signs Onset at 8-20 months, neonatally healthy Muscular hypotonia Acquired microcephaly Ataxia Visual failure Myoclonic jerks Anxiety and hyperkinesias of hands and forearms a t 12-24 months Restlessness and choreoathetosis at 20-36 months “Burn-out’’ stage at the age of 3 years Laboratory findings EEG: posterior low activity by 2 years, flat by 3 years VEP absent between 2 and 4 years ERG (noncorneal) absent between 2 and 4 years Retinal findings (optic atrophy, macular degeneration) Histology: lipofuscin-like storage bodies Electron microscopy: homogeneous finely granulated storage cytosomes
Polymorphic Markers The hybridization probes DlS57, DlS79, and DlS62 were provided by Dr. Ray White [OConnell et al., 19891, and the minisatellite probe D1S7 was donated by Alec Jeffreys [Wolff et al., 19891. Rh blood group determination is a routine paternity testing method in our laboratory [Aho and Leino, 1986; Helminen et al., 19881.
DNA Linkage Analyses and Linkage Calculations DNA was isolated from frozen peripheral blood samples of living patients and relatives or from frozen tissues of deceased children. Five micrograms of DNA of each individual was digested with several restriction enzymes, showing the polymorphisms, electrophoresed through a 20 cm long plate of 1% agarose gel for 17 hours at 70 V. After electrophoresis, DNA fragments were depurinated, denatured, transferred t o Hypond-N (Amersham), and hybridized according to standard procedures [Vandenplas et al., 19841.
RESULTS We first carried out two-point linkage analyses in our 20 INCL families for 5 markers located on the short arm of chromosome 1. The lod scores obtained at different recombination fractions are shown in Table 111. The maximum lod score was obtained in the highly polymorphic minisatellite probe DlS7, and no recombinations could be detected in our material ,Z,( = 4.55 at 8 = 0.00 with confidence interval 0.00-0.07). When analyzing the polymorphic markers in the vicinity of this marker, we detected 3 recombinations in 51 meiotic events studied between the disease locus and the marker DlS79 located 4 cM from DlS7. The linkage analysis resulted in a maximum lod score Z, = 1.89 at the recombination fraction 0.1. One obligatory recombination event was established between DlS57, located on the opposite side of DlS7,7 cM from it, and the disease locus, the linkage calculation giving the maximum lod , = 2.96 a t the recombination fraction 0.03. score,,Z Since D1S7 has been reliably located between DlS79 and DlS57 on the linkage map of chromosome 1[O’Connell et al., 1989; Wolff et al., 19891, our linkage data currently place the INCL locus between these 2 markers, which consequently flank the disease locus. A more precise location analysis based on the LINKMAP option of the linkage package demonstrated that the INCL gene can be located between DlS79 and DlS57, the most probable location being very close to D1S7 (Fig. 1). The polymorphic marker demonstrating the best linkage, DlS7, has numerous alleles and 99% heterozygosity, and we did not find a linkage disequilibrium of this marker in INCL chromosomes. The 2 flanking markers at some distance from the tentative INCL locus exist in 14 different haplotypes in phase-known INCL chromosomes and 9 of these haplotypes also in nonINCL chromosomes of 30 parents of these affected children. These high numbers are obviously due to the VNTR character of the flanking probes, one (DlS79) with 5, the other (DlS57) with 6 alleles. Anyway, the total lack of any linkage disequilibrium with these markers supports our LINKMAP based approximation of the current distances between the INCL locus and
TABLE 111. INCL Vs Chromosome 1 Markers Marker locus Rh DlS79 D1S7 DlS57 DlS62
0.00 -03
-m
4.55 -m
-m
0.01 - 0.82 -0.05 4.40 2.81 - 2.51
0.05 - 0.18 1.59 3.81 2.86 - 1.18
Recombination fraction (0) 0.1 0.2 -0.02 0.11 1.89 1.50 3.10 1.84 2.40 1.40 -0.67 - 0.25
0.3 0.07 0.81 0.86 0.63 --0.09
0.4 0.02 0.23 0.22 0.16 -- 0.02
548
Jarvela et al.
highly favourable for prenatal and carrier diagnostics in the analyzed families. Furthermore, a reliable linkage map with highly polymorphic markers in the vicinity of the INCL locus offers a good starting point and solid basis for reverse genetics aiming at detailed characterization of the INCL mutation. It will be highly interesting to expose the gene or genes so essential for normal brain development and function that their mutations result in rapid destruction of cortical neurons.
‘A‘
ACKNOWLEDGMENTS This project was funded by the Academy of Finland, and grants from the University of Helsinki, Finska Lakarsallskapet, and the Rinnekoti Research Foundation, ESPOO,Finland. We gratefully acknowledge the constant support of Drs. Juhani Rapola and Jorma Palo. Our discussions with Dr. Mark Gardiner were very fruitful. REFERENCES
Fig. 1. Location map summarizing the lod scores calculated for INCL gene at various map positions on a fixed marker map [Wolff et al., 19891. D1S7 has been arbitrarily placed at 0. The recombination frequencies (8) used between markers are Rh-0.062-DlS79-0.039DlS7-0.068-DlS57-0.082-DlS62. The multipoint analysis suggests chat the best location (DlS79-DlS57) favors with odds 33: 1 over the second-best location (DlS57-DlS62).
these markers: about 7 cM from DlS57 and 4 cM from DlS79.
DISCUSSION The mean age of Finnish INCL patients included in the study was 6.8 years, and only 5 ofthe 20 families had 2 affected children. The parents are reluctant to conceive again once INCL has been diagnosed in a child. Although prenatal diagnosis based on electron microscopic search for inclusions has been possible from chorion villus specimens [Rapolaet al., 19881,there is a risk of sampling error involved in this technically very demanding analysis. Prenatal diagnosis has now become possible with the demonstrated linkage of INCL to several informative DNA markers. With the current markers the error risk of DNA analysis due to recombinations is still 3-5%, a rate acceptable to most families. A combination of DNA testing and electron microscopic analysis of chorion villus biopsy specimens is currently used in Finland for prenatal diagnosis of INCL. The linkage relationships of chromosome 1 are well established in the region surrounding the INCL locus, and the distances between polymorphic VNTR markers have been determined precisely [O’Connell et al., 1989; Wolff et al., 19891. This is probably the reason that our linkage analyses were so informative and were able to detect the linkage of INCL in such a limited family material [Jarvela et al., 19911. This situation is also
Aho K, Leino U (1986): Paternity and blood group evidence. Int Comp Law Q 31:576-581. Gardiner RM, Sandford A, Deadman M, Poulton J, Cookson W, Reeders S, Jokiaho I, Peltonen L, Eiberg H, Julier C (1990): Batten disease (Spielmeyer-Vogt; juvenile onset neuronal ceroid lipofuscinosis) maps to human chromosome 16. Genomics 8:387-390. Haltia M (1987):Infantile neuronal ceroid lipofuscinosis: An inherited disorder with disturbed dolichol metabolism. Proceedings of the Twelfth Nobel Conference of the Karolinska Institute. Chemica Scripta 27:89-91. Helminen P, Ehnholm C, Lokki M-L, Jeffreys A, Peltonen L (1988): Application of DNA “fingerprints” to paternity determinations. Lancet 1574-576. Jarvela I, Schleutker J, Haataja L, Santavuori P, Puhakka L, Manninen T, Palotie A, Sandkuijl LA, Renlund M, White R, Aula P, Peltonen L (1991): Infantile neuronal ceroid lipofuscinosis (INCL, CLN1) maps to the short arm of chromosome 1. Genomics 9:170173. Jokiaho I, Puhakka L, Santavuori P, Manninen T, Nyman K, Peltonen L (1990): Infantile neuronal ceroid lipofuscinosis (INCL) is not an allelic form of Batten disease; exclusion of chromosome 16 region by linkage analyses. Genomics 8:391-393. Lathrop GM, Lalouel JM, Julier C, Ott J (1984):Strategies for multilocus linkage analysis in humans. Proc Natl Acad Ski USA 81:3433-3446. Nakamura Y, Leppert M, OConnell P, Wolff R, Holm T, Culver M, Martin C, Fujimoto E, Hoff M, Kumlin E, White R (1987): Variable number of tandem repeat (VNTR) markers for human gene mapping. Science 2351616-1622. OConnell P, Lathrop GM, Nakamura Y, Leppert ML, Ardinger RH, Murray JL, Lalouel J-M, White R (1989): Twenty-eight loci form a continuous linkage map of markers for human chromosome 1. Genomics 4:12-20. Rapola J, Santavuori P, Heiskala H (1988): Placental pathology and prenatal diagnosis of infantile type of neuronal ceroidlipofuscinosis. Am J Med Genet [Suppll 599-103. Santavuori P (1988):Neuronal ceroid lipofuscinosis in childhood. Brain Dev 1O:SO-83. Santavuori P, Haltia M, Rapola (1974): Infantile type of so-called neuronal ceroid lipofuscinosis. Dev Med Child Neurol 165644-653. Vandenplas S, Wud I, Grobler-Rabie A, Boyed C, Mathew C (1984): Blot hybridization analysis of genomic DNA. J Med Genet 21:164-172. Wolff RK, Plaetke R, Jeffreys A, White R (1989): Unequal crossingover is not the major mechanism involved in the generation of new alleles at VNTR loci. Genomics 5382-384.
Linkage Map of the Chromosomal Region Surrounding the Infantile Neuronal Ceroid Lipofuscinosis on l p Irma Jarvela, Pirkko Santavuori, Lea Puhakka, Matti Haltia, and Leena Peltonen Laboratory of Molecular Genetics, National Public Health Institute, Helsinki (I.J., L P . , L P . ) , Departments of Child Neurology (P.S.) and Pathology (M.H.), University of Helsinki, Helsinki, Finland The neuronal ceroid lipofuscinoses (NCLs) of childhood are divided into 3 main types according t o age-of-onset, clinical course, and neurophysiological and neuropathological findings: infantile, late infantile, and juvenile. All forms are inherited as a n autosomal recessive trait, and their biochemical background is still unknown. The infantile type (INCL) with the earliest age-of-onset a n d the most severe clinical course, occurs in Finland with an incidence of 1:20,000, i.e., 116patients have been found in our country up to now, whereas only about 50 cases have been reported from other parts of the world. Earlier we reported the linkage of INCL to the short a r m of chromosome 1. Here we describe a more precise linkage map of this area. Our current m a p places the INCL mutation between DlS57 and DlS79; D1S7 has so f a r shown no recombination events between the marker and the disease (lod score 4.55 at 0 = 0.00). Our material includes 64% of all living patients in Finland, and n o linkage disequilibrium of haplotypes is seen, using the 2 physically close markers DlS57 and DlS79. This finding as well as our LINKMAP analyses suggest that the distance between the disease locus and the flanking markers is about 3-4 cm.
KEY WORDS: NCL, chromosome 1, DNA diagnostics INTRODUCTION Neuronal ceroid lipofuscinosis (NCL) is a disease group characterized by progressive mental retardation, Received for publication April 5,1991; revision received July 15, 1991. Address reprint requests to Irma Jarvela, M.D., National Public Health Institute, Laboratory of Molecular Genetics, Mannerheimintie 166, 00300 Helsinki, Finland.
0 1992 Wiley-Liss, Inc.
blindness, ataxia, seizures, and accumulation of ceroidand lipofuscin-like storage cytosomes in various tissues due to unknown biochemical defect(s1. The childhood forms of the disease are divided into 3 different types: infantile (INCL, Santavuori-Haltia disease), late infantile (LINCL, Jansky-Bielschowsky disease, early onset Batten disease), and juvenile (JNCL, Spielmeyer-VogtSjogren, late onset Batten disease). All types are inherited as an autosomal recessive trait [Santavuori, 19881. The first signs of the most severe form, INCL, appear at age of 8-20 months. The main symptoms of this fatal disease are rapid psychomotor retardation, muscular hypotonia, ataxia, visual failure, myoclonic jerks, microcephaly, and knitting hyperkinesia (not in all patients). EEG approaches isoelectricity by age 3 years, and the mean age of death is about 10 years [Santavuori et al., 1974; Haltia, 19871. Linkage analyses have only recently established that INCL and JNCL are due to different mutations: The gene locus for JNCL has been mapped to chromosome 16 [Gardiner et al., 19901, whereas that of INCL has been localized to the short arm of chromosome 1 [Jokiaho et al., 1990; Jarvela et al., 19911by means of highly polymorphic VNTR (variable number of tandem repeat) markers [Nakamura et al., 19871. The gene locus of the third form, LINCL is still to be determined. MATERIALS AND METHODS Family Material The DNA samples of 20 Finnish INCL families were included in this study. These samples represent 64% of the living patients and their families in this country. In 5 INCL families there were 2 affected children, whereas in 15 families there was only one affected child. Twentysix healthy siblings were included in our materials (Table I). All patients were seen by one of the authors (P.S.), and the diagnosis was based on criteria summarized in Table 11: clinical course, neurophysiological, and ophthalmological findings and the electron microscopic changes of a rectal biopsy sample or of various tissues at autopsy in deceased children. Because INCL is a rare recessive disorder with the unique clinical picture enriched in a small isolated population, no heterogeneity was suspected.
Linkage Map of INCL TABLE I. INCL Families Studied
Fam 1 Fam 2 Fam 3 Fam 4 Fam 5 Fam 6-20
No. of affected children 2 2 2 2 2 1
547
The probes were radiolabeled with multiprime extension to a specific activity of 1-2 x lo9 cpndkg. Autoradiography was carried out on Kodak X-Omat films with intensifying screens for 4-7 days at - 80°C. Linkage analyses were carried out by the LINKAGE package computer program version, 5.03 [Lathrop et al., 19841, updated by Dr. Jurg Ott.
No. of unaffected children
0 1 1 1 1 22
TABLE 11. Clinical Characteristics of INCL Symptoms and signs Onset at 8-20 months, neonatally healthy Muscular hypotonia Acquired microcephaly Ataxia Visual failure Myoclonic jerks Anxiety and hyperkinesias of hands and forearms a t 12-24 months Restlessness and choreoathetosis at 20-36 months “Burn-out’’ stage at the age of 3 years Laboratory findings EEG: posterior low activity by 2 years, flat by 3 years VEP absent between 2 and 4 years ERG (noncorneal) absent between 2 and 4 years Retinal findings (optic atrophy, macular degeneration) Histology: lipofuscin-like storage bodies Electron microscopy: homogeneous finely granulated storage cytosomes
Polymorphic Markers The hybridization probes DlS57, DlS79, and DlS62 were provided by Dr. Ray White [OConnell et al., 19891, and the minisatellite probe D1S7 was donated by Alec Jeffreys [Wolff et al., 19891. Rh blood group determination is a routine paternity testing method in our laboratory [Aho and Leino, 1986; Helminen et al., 19881.
DNA Linkage Analyses and Linkage Calculations DNA was isolated from frozen peripheral blood samples of living patients and relatives or from frozen tissues of deceased children. Five micrograms of DNA of each individual was digested with several restriction enzymes, showing the polymorphisms, electrophoresed through a 20 cm long plate of 1% agarose gel for 17 hours at 70 V. After electrophoresis, DNA fragments were depurinated, denatured, transferred t o Hypond-N (Amersham), and hybridized according to standard procedures [Vandenplas et al., 19841.
RESULTS We first carried out two-point linkage analyses in our 20 INCL families for 5 markers located on the short arm of chromosome 1. The lod scores obtained at different recombination fractions are shown in Table 111. The maximum lod score was obtained in the highly polymorphic minisatellite probe DlS7, and no recombinations could be detected in our material ,Z,( = 4.55 at 8 = 0.00 with confidence interval 0.00-0.07). When analyzing the polymorphic markers in the vicinity of this marker, we detected 3 recombinations in 51 meiotic events studied between the disease locus and the marker DlS79 located 4 cM from DlS7. The linkage analysis resulted in a maximum lod score Z, = 1.89 at the recombination fraction 0.1. One obligatory recombination event was established between DlS57, located on the opposite side of DlS7,7 cM from it, and the disease locus, the linkage calculation giving the maximum lod , = 2.96 a t the recombination fraction 0.03. score,,Z Since D1S7 has been reliably located between DlS79 and DlS57 on the linkage map of chromosome 1[O’Connell et al., 1989; Wolff et al., 19891, our linkage data currently place the INCL locus between these 2 markers, which consequently flank the disease locus. A more precise location analysis based on the LINKMAP option of the linkage package demonstrated that the INCL gene can be located between DlS79 and DlS57, the most probable location being very close to D1S7 (Fig. 1). The polymorphic marker demonstrating the best linkage, DlS7, has numerous alleles and 99% heterozygosity, and we did not find a linkage disequilibrium of this marker in INCL chromosomes. The 2 flanking markers at some distance from the tentative INCL locus exist in 14 different haplotypes in phase-known INCL chromosomes and 9 of these haplotypes also in nonINCL chromosomes of 30 parents of these affected children. These high numbers are obviously due to the VNTR character of the flanking probes, one (DlS79) with 5, the other (DlS57) with 6 alleles. Anyway, the total lack of any linkage disequilibrium with these markers supports our LINKMAP based approximation of the current distances between the INCL locus and
TABLE 111. INCL Vs Chromosome 1 Markers Marker locus Rh DlS79 D1S7 DlS57 DlS62
0.00 -03
-m
4.55 -m
-m
0.01 - 0.82 -0.05 4.40 2.81 - 2.51
0.05 - 0.18 1.59 3.81 2.86 - 1.18
Recombination fraction (0) 0.1 0.2 -0.02 0.11 1.89 1.50 3.10 1.84 2.40 1.40 -0.67 - 0.25
0.3 0.07 0.81 0.86 0.63 --0.09
0.4 0.02 0.23 0.22 0.16 -- 0.02
548
Jarvela et al.
highly favourable for prenatal and carrier diagnostics in the analyzed families. Furthermore, a reliable linkage map with highly polymorphic markers in the vicinity of the INCL locus offers a good starting point and solid basis for reverse genetics aiming at detailed characterization of the INCL mutation. It will be highly interesting to expose the gene or genes so essential for normal brain development and function that their mutations result in rapid destruction of cortical neurons.
‘A‘
ACKNOWLEDGMENTS This project was funded by the Academy of Finland, and grants from the University of Helsinki, Finska Lakarsallskapet, and the Rinnekoti Research Foundation, ESPOO,Finland. We gratefully acknowledge the constant support of Drs. Juhani Rapola and Jorma Palo. Our discussions with Dr. Mark Gardiner were very fruitful. REFERENCES
Fig. 1. Location map summarizing the lod scores calculated for INCL gene at various map positions on a fixed marker map [Wolff et al., 19891. D1S7 has been arbitrarily placed at 0. The recombination frequencies (8) used between markers are Rh-0.062-DlS79-0.039DlS7-0.068-DlS57-0.082-DlS62. The multipoint analysis suggests chat the best location (DlS79-DlS57) favors with odds 33: 1 over the second-best location (DlS57-DlS62).
these markers: about 7 cM from DlS57 and 4 cM from DlS79.
DISCUSSION The mean age of Finnish INCL patients included in the study was 6.8 years, and only 5 ofthe 20 families had 2 affected children. The parents are reluctant to conceive again once INCL has been diagnosed in a child. Although prenatal diagnosis based on electron microscopic search for inclusions has been possible from chorion villus specimens [Rapolaet al., 19881,there is a risk of sampling error involved in this technically very demanding analysis. Prenatal diagnosis has now become possible with the demonstrated linkage of INCL to several informative DNA markers. With the current markers the error risk of DNA analysis due to recombinations is still 3-5%, a rate acceptable to most families. A combination of DNA testing and electron microscopic analysis of chorion villus biopsy specimens is currently used in Finland for prenatal diagnosis of INCL. The linkage relationships of chromosome 1 are well established in the region surrounding the INCL locus, and the distances between polymorphic VNTR markers have been determined precisely [O’Connell et al., 1989; Wolff et al., 19891. This is probably the reason that our linkage analyses were so informative and were able to detect the linkage of INCL in such a limited family material [Jarvela et al., 19911. This situation is also
Aho K, Leino U (1986): Paternity and blood group evidence. Int Comp Law Q 31:576-581. Gardiner RM, Sandford A, Deadman M, Poulton J, Cookson W, Reeders S, Jokiaho I, Peltonen L, Eiberg H, Julier C (1990): Batten disease (Spielmeyer-Vogt; juvenile onset neuronal ceroid lipofuscinosis) maps to human chromosome 16. Genomics 8:387-390. Haltia M (1987):Infantile neuronal ceroid lipofuscinosis: An inherited disorder with disturbed dolichol metabolism. Proceedings of the Twelfth Nobel Conference of the Karolinska Institute. Chemica Scripta 27:89-91. Helminen P, Ehnholm C, Lokki M-L, Jeffreys A, Peltonen L (1988): Application of DNA “fingerprints” to paternity determinations. Lancet 1574-576. Jarvela I, Schleutker J, Haataja L, Santavuori P, Puhakka L, Manninen T, Palotie A, Sandkuijl LA, Renlund M, White R, Aula P, Peltonen L (1991): Infantile neuronal ceroid lipofuscinosis (INCL, CLN1) maps to the short arm of chromosome 1. Genomics 9:170173. Jokiaho I, Puhakka L, Santavuori P, Manninen T, Nyman K, Peltonen L (1990): Infantile neuronal ceroid lipofuscinosis (INCL) is not an allelic form of Batten disease; exclusion of chromosome 16 region by linkage analyses. Genomics 8:391-393. Lathrop GM, Lalouel JM, Julier C, Ott J (1984):Strategies for multilocus linkage analysis in humans. Proc Natl Acad Ski USA 81:3433-3446. Nakamura Y, Leppert M, OConnell P, Wolff R, Holm T, Culver M, Martin C, Fujimoto E, Hoff M, Kumlin E, White R (1987): Variable number of tandem repeat (VNTR) markers for human gene mapping. Science 2351616-1622. OConnell P, Lathrop GM, Nakamura Y, Leppert ML, Ardinger RH, Murray JL, Lalouel J-M, White R (1989): Twenty-eight loci form a continuous linkage map of markers for human chromosome 1. Genomics 4:12-20. Rapola J, Santavuori P, Heiskala H (1988): Placental pathology and prenatal diagnosis of infantile type of neuronal ceroidlipofuscinosis. Am J Med Genet [Suppll 599-103. Santavuori P (1988):Neuronal ceroid lipofuscinosis in childhood. Brain Dev 1O:SO-83. Santavuori P, Haltia M, Rapola (1974): Infantile type of so-called neuronal ceroid lipofuscinosis. Dev Med Child Neurol 165644-653. Vandenplas S, Wud I, Grobler-Rabie A, Boyed C, Mathew C (1984): Blot hybridization analysis of genomic DNA. J Med Genet 21:164-172. Wolff RK, Plaetke R, Jeffreys A, White R (1989): Unequal crossingover is not the major mechanism involved in the generation of new alleles at VNTR loci. Genomics 5382-384.
