Eur. Neurol. 18: 91-95 (1979)
Detection and Genetic Counselling of Subclinical and Carrier States in Duchenne Muscular Dystrophy1 Prasanta Kumar Das and Shyamal Kumar Sen Departments o f Medicine and Neurology. Medical College Hospitals, Calcutta
Key Words. Duchenne carriers • Steroid-CPK test • Genetic counselling Abstract. 23 potential carriers of Duchenne muscular dystrophy (DMD) and 20 of their apparently healthy brothers were studied for evidence of any subclinical form o f the disease. The results of the study confirmed that it was possible to confirm tire diagnosis of a ‘high genetic risk’ carrier by integrating the results of clinical studies, estimation of basal serum CPK, steroid-CPK test, EMG and ECG observations. Similarly, the subclinical state of DMD could also be detected with certainty in 10% o f the brothers of DMD carriers. The results may be applied for genetic counselling to bring down the incidence of the disease in the community.
1 Financial assistance received from CSIR, Govern ment of India.
investigations wlrich were carried out on poten tial DMD carriers and their healthy brothers for tire diagnosis of subclinical states. Materials and Methods 23 potential carriers of DMD, 1 8 -3 0 years of age, were selected for the present study to help them regarding marriage and childbirth. They were divided into three categories definite, probable and possible (Pearce et a i, 1964). 20 apparently unaffected broth ers o f the DMD subjects, aged 0 -3 0 years, were also included in the study for detection o f subclinical states. 10 normal healthy subjects, matched to age, sex and socioeconomic conditions, were used as controls. Clinical Study. The birth history, history of mile stones o f growth, history o f any difficulty in walking and any muscular weakness were specially enquired about.
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From the point of genetic counselling, it is important to detect carriers of X-linked Duch enne muscular dystrophy (DMD) to bring down the incidence of the disease in the community. It is equally important to determine the sub clinical state of DMD for genetic counselling because tire gene for DMD is usually 100% penetrant in lrenrizygous (XY) males but some reports suggested that males may be hemizygous for the mutant gene without clinical symp toms (Thomson et al., 1962; Richterich et ai, 1963). The purpose o f this communication, therefore, is to record tire results of various
Das/Sen
92
Serum CPK (SCPK) Study. This was estimated by the method of Okinaka et al. (1961) in each subject on three occasions after a rest o f 1 h. The normal range of activity noted in our laboratory was 0 —5 units. Steroid-CPK Test. In all the subjects, the SCPK activity was also observed after administration of intravenous hydrocortisone (1 mg/kg body weight) to note whether there was any increase, as was demon strated in patients o f neuromuscular disorders (Takahasi et al.. 1975; Sen and Das, 1977). Electromyographic Observations. The myopathic changes after maximal volitions were classified into 3 grades (Smith et al., 1966). Electrocardiography. The average of three readings (sum of R-S waves) was recorded in each person for evidence of any abnormality. Values for R-S in V, in children were taken as normal according to Nadas (1963) and in adults according to Emery (1972). The subjects were given a score out o f a maximum score of 18, after integrating the results o f the above studies. Scores were analysed as follows.
=6
Discussion
The SCPK estimation is regarded as the most sensitive index for detection of carriers and it Iras been stressed that multiple estimations in crease the accuracy of the method (McCormick and Allen, 1976). Thus at least three basal SCPK estimations were done in each case of the present series. Previously SCPK activity was reported to increase after steroids in DMD cases
Changes
Mild Moderate Marked 2 EMG 3 (i) SCPK (ii) Steroid-CPK test 4 ECG
=6 =3 =1 =2
Present on one side
on both sides
1 2 3
2 4 6
(analysed as above) (1 for raised CPK on each occasion) (negative = 0, positive = 1) (normal = 0, abnormal = 2)
Muscle Biopsy. Potential carriers of DMD having scores below 4 and all their brothers with suspected ‘subclinical’ status were requested to undergo this test for further assessment.
Results
In 23 cases of potential DMD carriers, 4 cases were regarded as ‘carriers' (score > 8 ), 6 patients were considered ‘presumptive’ DMD carriers (scores = 4 -7 ), another 5 cases were
{'Takahasi et al., 1975; Sen and Das, 1977; 1978a, b). As the carriers are regarded to be suffering from a subclinical form of the disease {Lyon, 1961), any specificity of steroid-CPK test was explored in these cases also. The effectiveness of the present method of combination of these four parameters of study may be judged by analysis of the results in the carrier group. In the cases with known genetic status, 2 definite carriers were later confirmed
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1 Clinical features
thought to be ‘possibly non-carriers’ (scores = 2—3) and the rest, 8 subjects, were taken as ‘non-carriers’ (scores < 2 ) (table I). Among the healthy brothers, 2 boys showed moderate to marked changes (scores > 8 ) and were regarded as ‘subclinical’ cases, 4 other male siblings were considered subjects with ‘possible’ subclinical status (scores = 2 -7 ) (table II).
93
Subclinical and Carrier States in Duchenne Muscular Dystrophy
Table I. Evaluation o f carriers Case No.
Type of carrier
Clinical assessment
actual level a Maximum score
6
possible possible probable possible possible definite possible possible possible probable possible possible definite possible possible probable possible probable possible possible possible probable possible
0 0 0 0 TAC 1 0 0 0 0 0 0 1 4 0 1 0 0 0 0 2 0 0 0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
SteroidCPK test
F.CG EMG Total Conclusion score
3
1
2
6
18
1 0 2 0 2 2 0 2 2 1 0 1 3 0 3 2 1 0 1 3 0 0 1
0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0
0 0 2 0 0 2 0 0 0 0 0 0 0 0 2 2 0 0 0 0 0 0 0
2 0 1 0 2 3 0 2 2 1 0 2 4 0 3 3 2 1 2 4 0 0 3
3 0 5 0 5 8 0 4 5 2 0 4 12 0 9 7 3 1 3 10 0 1 4
Biochemical assessment basal SCPK
2 4 4 3 12 5 4 4 2 3 3 2 49 0 21 4 3 2 4 98 0 2 3
b
12 3 14 5 18 27 0 14 20 8 5 10 48 0 15 12 4 0 5 124 5 3 8
score c
3 2 18 4 0 18 0 9 21 4 0 4 56 3 18 19 8 3 18 112 4 4 4
PNC NC PC NC PC carrier NC PC PC PNC NC PC carrier NC carrier PC PNC NC PNC carrier NC NC PNC
as ‘carrier’, whereas only 7 cases were thought to be known carriers (definite and probable) from tlie family history, 10 cases (43.5%) were later found to have a high genetic risk of carrying the affected gene (earners and pre sumptive carriers). Thus the ‘high-risk’ carrier detection rate actually improved by the present method of study of integrating the results of
clinical studies, estimation of basal serum CPK, steroid-CPK. test, EMG and ECG observations. 13 cases of suspected carriers (probable non carriers and non-carriers) were requested to undergo ‘muscle biopsy’ for further assessment. None of them demonstrated any abnormal mus cle biopsy picture and thus apparently this particular investigation was not of much help in
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PC = Presumptive carrier; PNC = probably non-carrier; NC = non-carrier; TAC = Tendo Achilles contracture, a, b and c are the actual SCPK activities on three occasions.
94
Das/Scn
Table II. Evaluation of unaffected brothers Case No.
Clinical assessment
Biochemical assessment basal SCPK actual level a
b
0 1 4
0 4 22 14 11 15
3 14 40 3 20 13
ECG
EMG Total Conclusion score
3
1
2
6
18
1 2 3 2 3 3
_
_
2
-
—
—
-
-
-
-
-
-
-
2
4 2 3 4
3 3 11 4 6 9
score c
Maximum score 6 1 8 11 14 17 19
Steroid CPK test
11 18 31 9 18 9
P P SC P P SC
these cases for more definite results. Among the group of apparently unaffected brothers, 2 male siblings (subclinical) and 4 other boys with ‘possible subclinical’ state later underwent muscle biopsy. Though 1 of the ‘subclinical’ cases (No. 7) showed an increase of interstial fat in muscle biopsy, the histopathological study in others, could not yield any further information. It is well known that in X-linked recessive inheritance, any son of a female carrier has a 50% chance of being affected and any daughter has a 50% chance of being a carrier. Thus, the risk that a carrier will produce an affected male in a given pregnancy is 25%. To help in repro ductive planning, all the potential carriers were appraised of these facts in the light of the results of this study. They were further assured that one third of all cases of DMD were bom from a new mutation in the ovum of a geneti cally normal mother and, as such, female rela
tives of such cases do not have any increased risk of producing DMD children. Most of these ‘high genetic risk’ carriers decided either not to have children or to have future pregnancies guided by aminocentesis for determination of fetal sex and thus to terminate male children. Two couples considered surgical sterilisation. During the counselling of the brothers, it was intimated that the DMD subjects did not repro duce usually but it was, however, possible for a DMD boy with a less penetrating diseased Xgene to transmit the disease to homozygous daughters when married to a female carrier. The ‘subclinical’ cases were also made aware of the high probability of development of the disease later and requested to attend the out-patient department for follow up. The impact of this genetic counselling on the reproductive plan ning of DMD families may be found interesting in further studies of these cases, though one third of DMD cases are new mutants.
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Only 6 cases with definite ‘subclinical’ state or 'possible' subclinical state are shown, among a group of 20 apparently healthy unaffected brothers o f DMD subjects. SC = ‘Subclinical’ state; P = 'possible' subclinical state, a, b and c are the actual SCPK activities on three occasions.
Subdinical and Carrier States in Duchenne Muscular Dystrophy
We are grateful to the Principal-Superintendent, Medical College Hospitals, Calcutta, for granting us permission to use the hospital records. We are also thankful to Dr. AT. Manocha, Dr. A. Mukherjee, Dr. K. Chatterjee, Mr. Tapan Chakraborty, Mr. Robin Chatterjee and Mr. Jyotirm oy Chaudhury for render ing us active help in various fields of this study.
References Emery, A.E.H.: Abnormalities of the electrocardio gram in hereditary myopathies. J. med. Genet. 9: 8 (1972). Lyon, M.F.: Nature, Lond. 190: 372(1961). (Quoted by McCormick and Allen, 1976.) McCormick, D. and Allen, I.V.: Serum creatine phosphokinase in the detection of carriers of Duchenne’s muscular dystrophy in Northern Ireland. Ulster med. J. 45: 79 (1976). Nadas, A.S.: Pediatric cardiology; 2nd ed., p. 71 (Saunders, Philadelphia 1963). Okinaka, S.; Kumagai, H.; Ebashi, S.; Sugita, H.; Momos, H.; Toyokura, Y., and Fugie, Y.: Serum creatine phosphokinase. Archs Neurol., Chicago 4: 520(1961). Pearce, J.M.S.; Pennington, R.J., and Walton, J.N.: Serum enzyme studies in muscle disease. III. Serum creatine kinase activity in relatives of patients with the Duchenne type o f muscular dystrophy. J. Neurol. Neurosurg. Psychiat. 27; 181 (1964).
Richterich, R.; Rosin, S.; Aebi, U., and Rossi, E.: Progressive muscular dystrophy. V. The identifica tion of carrier state by serum creatine kinase determination. Am. J. hum. Genet. 15: 133 (1963). Sen, S. and Das, P.K.: Steroid CPK test - a new diagnostic aid for muscular dystrophy and its carriers? Abstract. Neurol. India 15: 196 (1977). Sen, S. and Das, P.K.: Steroid CPK test - a new diagnostic aid for muscular dystrophy and its carriers? Eur. Neurol. 17: 5 (1978a). Sen, S. and Das, P.K.; Steroid-induced CPK estimation - a new diagnostic test for human muscular dys trophy and its carrier state. Archs Dis. Childh. 53: 6 (1978b). Smith, H.L.; Amick, L.D., and Johnson, W.W.: Detec tion of sub-clinical and carrier states in Duchenne muscular dystrophy. J. Pediat. 69: 6 7 -7 9 (1966). Takahasi, K.; Oimomi, M.; Shinko, T.; Shutta, K.; Matsuo, B.; Takai, T., and Imura, H.: Response of serum creatine phosphokinase to steroid hormone. Archs Neurol., Chicago 32: 89 (1975). Thompson, M.W.; Ludvigsen, B., and Monckton, G.: Some problems in genetics of muscular dystrophy. Revue can. Biol. 21: 543 (1962).
Received: June 27, 1978 Accepted: June 27, 1978 Prof. Shyamal Sen, 63 Lenin Sarani, Calcutta 700013 (India)
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Acknowledgements
95
Detection and Genetic Counselling of Subclinical and Carrier States in Duchenne Muscular Dystrophy1 Prasanta Kumar Das and Shyamal Kumar Sen Departments o f Medicine and Neurology. Medical College Hospitals, Calcutta
Key Words. Duchenne carriers • Steroid-CPK test • Genetic counselling Abstract. 23 potential carriers of Duchenne muscular dystrophy (DMD) and 20 of their apparently healthy brothers were studied for evidence of any subclinical form o f the disease. The results of the study confirmed that it was possible to confirm tire diagnosis of a ‘high genetic risk’ carrier by integrating the results of clinical studies, estimation of basal serum CPK, steroid-CPK test, EMG and ECG observations. Similarly, the subclinical state of DMD could also be detected with certainty in 10% o f the brothers of DMD carriers. The results may be applied for genetic counselling to bring down the incidence of the disease in the community.
1 Financial assistance received from CSIR, Govern ment of India.
investigations wlrich were carried out on poten tial DMD carriers and their healthy brothers for tire diagnosis of subclinical states. Materials and Methods 23 potential carriers of DMD, 1 8 -3 0 years of age, were selected for the present study to help them regarding marriage and childbirth. They were divided into three categories definite, probable and possible (Pearce et a i, 1964). 20 apparently unaffected broth ers o f the DMD subjects, aged 0 -3 0 years, were also included in the study for detection o f subclinical states. 10 normal healthy subjects, matched to age, sex and socioeconomic conditions, were used as controls. Clinical Study. The birth history, history of mile stones o f growth, history o f any difficulty in walking and any muscular weakness were specially enquired about.
Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 1/17/2019 12:47:36 PM
From the point of genetic counselling, it is important to detect carriers of X-linked Duch enne muscular dystrophy (DMD) to bring down the incidence of the disease in the community. It is equally important to determine the sub clinical state of DMD for genetic counselling because tire gene for DMD is usually 100% penetrant in lrenrizygous (XY) males but some reports suggested that males may be hemizygous for the mutant gene without clinical symp toms (Thomson et al., 1962; Richterich et ai, 1963). The purpose o f this communication, therefore, is to record tire results of various
Das/Sen
92
Serum CPK (SCPK) Study. This was estimated by the method of Okinaka et al. (1961) in each subject on three occasions after a rest o f 1 h. The normal range of activity noted in our laboratory was 0 —5 units. Steroid-CPK Test. In all the subjects, the SCPK activity was also observed after administration of intravenous hydrocortisone (1 mg/kg body weight) to note whether there was any increase, as was demon strated in patients o f neuromuscular disorders (Takahasi et al.. 1975; Sen and Das, 1977). Electromyographic Observations. The myopathic changes after maximal volitions were classified into 3 grades (Smith et al., 1966). Electrocardiography. The average of three readings (sum of R-S waves) was recorded in each person for evidence of any abnormality. Values for R-S in V, in children were taken as normal according to Nadas (1963) and in adults according to Emery (1972). The subjects were given a score out o f a maximum score of 18, after integrating the results o f the above studies. Scores were analysed as follows.
=6
Discussion
The SCPK estimation is regarded as the most sensitive index for detection of carriers and it Iras been stressed that multiple estimations in crease the accuracy of the method (McCormick and Allen, 1976). Thus at least three basal SCPK estimations were done in each case of the present series. Previously SCPK activity was reported to increase after steroids in DMD cases
Changes
Mild Moderate Marked 2 EMG 3 (i) SCPK (ii) Steroid-CPK test 4 ECG
=6 =3 =1 =2
Present on one side
on both sides
1 2 3
2 4 6
(analysed as above) (1 for raised CPK on each occasion) (negative = 0, positive = 1) (normal = 0, abnormal = 2)
Muscle Biopsy. Potential carriers of DMD having scores below 4 and all their brothers with suspected ‘subclinical’ status were requested to undergo this test for further assessment.
Results
In 23 cases of potential DMD carriers, 4 cases were regarded as ‘carriers' (score > 8 ), 6 patients were considered ‘presumptive’ DMD carriers (scores = 4 -7 ), another 5 cases were
{'Takahasi et al., 1975; Sen and Das, 1977; 1978a, b). As the carriers are regarded to be suffering from a subclinical form of the disease {Lyon, 1961), any specificity of steroid-CPK test was explored in these cases also. The effectiveness of the present method of combination of these four parameters of study may be judged by analysis of the results in the carrier group. In the cases with known genetic status, 2 definite carriers were later confirmed
Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 1/17/2019 12:47:36 PM
1 Clinical features
thought to be ‘possibly non-carriers’ (scores = 2—3) and the rest, 8 subjects, were taken as ‘non-carriers’ (scores < 2 ) (table I). Among the healthy brothers, 2 boys showed moderate to marked changes (scores > 8 ) and were regarded as ‘subclinical’ cases, 4 other male siblings were considered subjects with ‘possible’ subclinical status (scores = 2 -7 ) (table II).
93
Subclinical and Carrier States in Duchenne Muscular Dystrophy
Table I. Evaluation o f carriers Case No.
Type of carrier
Clinical assessment
actual level a Maximum score
6
possible possible probable possible possible definite possible possible possible probable possible possible definite possible possible probable possible probable possible possible possible probable possible
0 0 0 0 TAC 1 0 0 0 0 0 0 1 4 0 1 0 0 0 0 2 0 0 0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
SteroidCPK test
F.CG EMG Total Conclusion score
3
1
2
6
18
1 0 2 0 2 2 0 2 2 1 0 1 3 0 3 2 1 0 1 3 0 0 1
0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0
0 0 2 0 0 2 0 0 0 0 0 0 0 0 2 2 0 0 0 0 0 0 0
2 0 1 0 2 3 0 2 2 1 0 2 4 0 3 3 2 1 2 4 0 0 3
3 0 5 0 5 8 0 4 5 2 0 4 12 0 9 7 3 1 3 10 0 1 4
Biochemical assessment basal SCPK
2 4 4 3 12 5 4 4 2 3 3 2 49 0 21 4 3 2 4 98 0 2 3
b
12 3 14 5 18 27 0 14 20 8 5 10 48 0 15 12 4 0 5 124 5 3 8
score c
3 2 18 4 0 18 0 9 21 4 0 4 56 3 18 19 8 3 18 112 4 4 4
PNC NC PC NC PC carrier NC PC PC PNC NC PC carrier NC carrier PC PNC NC PNC carrier NC NC PNC
as ‘carrier’, whereas only 7 cases were thought to be known carriers (definite and probable) from tlie family history, 10 cases (43.5%) were later found to have a high genetic risk of carrying the affected gene (earners and pre sumptive carriers). Thus the ‘high-risk’ carrier detection rate actually improved by the present method of study of integrating the results of
clinical studies, estimation of basal serum CPK, steroid-CPK. test, EMG and ECG observations. 13 cases of suspected carriers (probable non carriers and non-carriers) were requested to undergo ‘muscle biopsy’ for further assessment. None of them demonstrated any abnormal mus cle biopsy picture and thus apparently this particular investigation was not of much help in
Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 1/17/2019 12:47:36 PM
PC = Presumptive carrier; PNC = probably non-carrier; NC = non-carrier; TAC = Tendo Achilles contracture, a, b and c are the actual SCPK activities on three occasions.
94
Das/Scn
Table II. Evaluation of unaffected brothers Case No.
Clinical assessment
Biochemical assessment basal SCPK actual level a
b
0 1 4
0 4 22 14 11 15
3 14 40 3 20 13
ECG
EMG Total Conclusion score
3
1
2
6
18
1 2 3 2 3 3
_
_
2
-
—
—
-
-
-
-
-
-
-
2
4 2 3 4
3 3 11 4 6 9
score c
Maximum score 6 1 8 11 14 17 19
Steroid CPK test
11 18 31 9 18 9
P P SC P P SC
these cases for more definite results. Among the group of apparently unaffected brothers, 2 male siblings (subclinical) and 4 other boys with ‘possible subclinical’ state later underwent muscle biopsy. Though 1 of the ‘subclinical’ cases (No. 7) showed an increase of interstial fat in muscle biopsy, the histopathological study in others, could not yield any further information. It is well known that in X-linked recessive inheritance, any son of a female carrier has a 50% chance of being affected and any daughter has a 50% chance of being a carrier. Thus, the risk that a carrier will produce an affected male in a given pregnancy is 25%. To help in repro ductive planning, all the potential carriers were appraised of these facts in the light of the results of this study. They were further assured that one third of all cases of DMD were bom from a new mutation in the ovum of a geneti cally normal mother and, as such, female rela
tives of such cases do not have any increased risk of producing DMD children. Most of these ‘high genetic risk’ carriers decided either not to have children or to have future pregnancies guided by aminocentesis for determination of fetal sex and thus to terminate male children. Two couples considered surgical sterilisation. During the counselling of the brothers, it was intimated that the DMD subjects did not repro duce usually but it was, however, possible for a DMD boy with a less penetrating diseased Xgene to transmit the disease to homozygous daughters when married to a female carrier. The ‘subclinical’ cases were also made aware of the high probability of development of the disease later and requested to attend the out-patient department for follow up. The impact of this genetic counselling on the reproductive plan ning of DMD families may be found interesting in further studies of these cases, though one third of DMD cases are new mutants.
Downloaded by: Karolinska Institutet, University Library 130.237.122.245 - 1/17/2019 12:47:36 PM
Only 6 cases with definite ‘subclinical’ state or 'possible' subclinical state are shown, among a group of 20 apparently healthy unaffected brothers o f DMD subjects. SC = ‘Subclinical’ state; P = 'possible' subclinical state, a, b and c are the actual SCPK activities on three occasions.
Subdinical and Carrier States in Duchenne Muscular Dystrophy
We are grateful to the Principal-Superintendent, Medical College Hospitals, Calcutta, for granting us permission to use the hospital records. We are also thankful to Dr. AT. Manocha, Dr. A. Mukherjee, Dr. K. Chatterjee, Mr. Tapan Chakraborty, Mr. Robin Chatterjee and Mr. Jyotirm oy Chaudhury for render ing us active help in various fields of this study.
References Emery, A.E.H.: Abnormalities of the electrocardio gram in hereditary myopathies. J. med. Genet. 9: 8 (1972). Lyon, M.F.: Nature, Lond. 190: 372(1961). (Quoted by McCormick and Allen, 1976.) McCormick, D. and Allen, I.V.: Serum creatine phosphokinase in the detection of carriers of Duchenne’s muscular dystrophy in Northern Ireland. Ulster med. J. 45: 79 (1976). Nadas, A.S.: Pediatric cardiology; 2nd ed., p. 71 (Saunders, Philadelphia 1963). Okinaka, S.; Kumagai, H.; Ebashi, S.; Sugita, H.; Momos, H.; Toyokura, Y., and Fugie, Y.: Serum creatine phosphokinase. Archs Neurol., Chicago 4: 520(1961). Pearce, J.M.S.; Pennington, R.J., and Walton, J.N.: Serum enzyme studies in muscle disease. III. Serum creatine kinase activity in relatives of patients with the Duchenne type o f muscular dystrophy. J. Neurol. Neurosurg. Psychiat. 27; 181 (1964).
Richterich, R.; Rosin, S.; Aebi, U., and Rossi, E.: Progressive muscular dystrophy. V. The identifica tion of carrier state by serum creatine kinase determination. Am. J. hum. Genet. 15: 133 (1963). Sen, S. and Das, P.K.: Steroid CPK test - a new diagnostic aid for muscular dystrophy and its carriers? Abstract. Neurol. India 15: 196 (1977). Sen, S. and Das, P.K.: Steroid CPK test - a new diagnostic aid for muscular dystrophy and its carriers? Eur. Neurol. 17: 5 (1978a). Sen, S. and Das, P.K.; Steroid-induced CPK estimation - a new diagnostic test for human muscular dys trophy and its carrier state. Archs Dis. Childh. 53: 6 (1978b). Smith, H.L.; Amick, L.D., and Johnson, W.W.: Detec tion of sub-clinical and carrier states in Duchenne muscular dystrophy. J. Pediat. 69: 6 7 -7 9 (1966). Takahasi, K.; Oimomi, M.; Shinko, T.; Shutta, K.; Matsuo, B.; Takai, T., and Imura, H.: Response of serum creatine phosphokinase to steroid hormone. Archs Neurol., Chicago 32: 89 (1975). Thompson, M.W.; Ludvigsen, B., and Monckton, G.: Some problems in genetics of muscular dystrophy. Revue can. Biol. 21: 543 (1962).
Received: June 27, 1978 Accepted: June 27, 1978 Prof. Shyamal Sen, 63 Lenin Sarani, Calcutta 700013 (India)
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Acknowledgements
95
