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Genetic markers of familial coronary heart disease
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463—also results in the loss of an MspI site. This arginine-tocysteine mutation has been identified in both type 1 and type 3 Gaucher disease and was present in 11of 62 patients.’ If the 463 mutation were present Dahl and colleagues’ 598 bp segment of DNA would not be cleaved to 580 bp, and this subtle difference might not be appreciated on a 1-2% gel. (Incidentally, the bands in the illustration provided by Dahl et al seem to be mislabelled in respect of size.) Investigators screening for gene mutations in Gaucher’s disease should be aware of the 463 mutation. If Msp is used for screening, the laboratory should amplify a larger DNA segment, so that the presence and/or absence of both the 444 and 463 mutations can be established simultaneously. Use of the technique described by Dahl et al may lead to errors in genetic counselling when applied to a population other than the Norrbottnian Gaucher patients. Clinical Neuroscience Branch, Section of Molecular Neurogenetics, National Institute of Mental Health, Bethesda, Maryland 20892, USA
ELLEN SIDRANSKY KARA MAYSAK EDWARD I. GINNS
1 Tsuji S, Choudary PW, Martin BM, et al. A mutation in the human glucocerebrosidase gene in neuronopathic Gaucher’s disease. N Engl J Med 1987; 316: 570-75. 2. Martin BM, Sidransky E, Ginns EI. Gaucher disease: advances and challenges. Adv Pediatr 1989; 36: 277-306. 3 Hong CM, Oshashi T, Yu YJ, Weiler S, Barranger JA Sequence of two alleles responsible for Gaucher’s disease. DNA Cell Biol 1990; 9: 232-41 4. Sidransky E, Tsuji S, Stubblefield B, Martin BM, Ginns EI Current genotypic analysis does not adequately account for phenotypic variation in Gaucher patients. Vth International Congress of Inborn Errors of Metabolism; OC4 7 (abstr).
Genetic markers of familial coronary heart disease SIR,-We have reported’ that in 713 men aged 30-59 a history of coronary heart disease (CHD) before age 60 in first-degree relatives
is associated with a significantly increased frequency of CHD morbidity in those who have DNA restriction fragment length polymorphism (RLFP) markers of the apolipoprotein AI/CIII/ AIV gene cluster. The RLFP are the minor alleles (X2, M2, Pz, Sz) of four biallelic markers identified with the enzymes XmnI, MspI, PstI, and SacI, respectively. We have now examined these men for allele status at a fifth RLFP in this gene region. This region identified by PvulI is in the first intron of the Apo CIII gene. DNA stored at - 20°C was digested with PvuII and DNA fragments were separated by electrophoresis and transferred to nitrocellulose filters after denaturation. The filters were then hybridised with a labelled CIII cDNA probe (pAT/CIII/8, kindly provided by Dr C. C. Shoulders). This probe identifies a constant fragment 1 ’4 kb in length and variable fragments of 1 kb (major allele, VI) and 0,87 kb (minor allele, Vz), the allele frequencies being 0-763 and 0’237, respectively. An increased frequency of V, has been reported in patients with angiographically proven CHDIn our study Vz frequency was not increased in men with CHD; the relative CHD frequency is significantly higher in men homozygous for Vl, although only in those who have one or more of the minor alleles, Xz
M2, P2, S2 (p < 0001). The five markers
are no more
than 10 kb bases apart. Of 32 11(a-k, table). Men with
possible haplotypes we are able to identify
APO Al/Clll/AIV MARKER HAPLOTYPES
haplotypes c-h have a higher relative premature CHD frequency of 2-00 (n 278; p < 0-001). The relative frequency is higher when 2 or more first-degree relatives are affected but the numbers are small and the difference is not significant. In a logistic regression analysis neither family history on its own nor haplotypes c-h emerges as a significant co-variable of CHD morbidity, but when the two are combined the odds ratio is 2 92 (95% confidence limits 1’91-3-91; p=0016). If the variables age, social class, smoking habits, blood pressure, plasma levels of cholesterol, apolipoproteins AI and B, triglycerides, and total cholesterol/HDL cholesterol ratios are included in the analysis, the co-variate adjusted odds ratio for CHD morbidity and haplotypes c-h in men with a family history of premature CHD is 2-73 (1 72-3 73; p 0023). The higher prevalence of premature familial CHD morbidity in those with haplotypes c to h is therefore independent of other major CHD risk factors. The selective association of some marker haplotypes in the region of the AI/CIII/AIV genes with significantly higher frequencies of familial CHD morbidity supports the conclusion that liability to CHD is enhanced by variants of one or more of these genes or of their regulators. =
=
MRC Human Genetics Unit, University Department of Medicine and Department of Clinical Chemistry, Western General Hospital, Edinburgh EH4 2XU, UK
W. H. PRICE S. W. MORRIS A. H. KITCHIN P. R. WENHAM P. R. S. MCKENZIE P. M. DONALD
1. Price WH, Morris SW, Kitchin AH, Wenham PR, Burgon PRS, Donald PM. DNA restriction fragment length polymorphisms as markers of familial coronary heart disease Lancet 1989; i: 1407-11. 2. Coleman RT, Gonzalez PA, Funke H, Assmann G, Levy-Wilson B, Frossard PM. Polymorphisms in the apolipoprotein AI-CIII gene complex. Mol Biol Med 1986; 3: 213-28. 3. Frossard PM, Funke H, Coleman RT, Assmann G. Genetic markers for coronary atherosclerosis in the human apolipoprotein AI-CIII-AIV gene complex. Am J Hum Gener 1986; 39: A199.
Secondary metabolic defects in spinal muscular atrophy type II SiR,—The genetic mapping of chronic childhood-onset spinal muscular atrophy types II (intermediate) and III (KugelbergWelander disease) and of acute SMA (type I, Werdnig-Hoffmann disease) allows prenatal diagnosis in informative families (Dr Melki and colleagues, Aug 4, p 271). However, this advance does not provide the early prospect of any specific therapy for children with these diseases. Any palliative treatment should be considered. We here report metabolic studies in 14 children (6 boys, 8 girls) with SMA type 11.1 Muscle biopsy findings were typical of SMA type II. In one biopsy sample there was a mild and in another a clear increase in the lipid content of type I fibres. Every patient had a typical electromyographic neurogenic pattern. By age at metabolic study the patients could be divided into three groups: Group 1, aged 1-3 years (n=5; age at onset, birth [1 floppy infant] to 18 months). 3 children could not maintain a sitting position; 1 could not stand up when supported, and 1 could. Group 2, aged J- 5 years (n=5, age at onset, 6-18 months). These children had acquired, with a delay, a very unsteady gait. Children with SMA type II are never able to walk.’ Nonetheless the early onset and the muscle biopsy findings were typical of SMA type II. This group may represent borderline cases between SMA type II and type 111.1 Group 3, aged C-/ 7 5 years (n = 4; age at onset, 9-18 months). These children were wheelchair-bound, and had some respiratory
problems. of organic acids in abnormal excretion of ethylmalonic acid in all 14 children, of methylsuccinic acid in 9, of glutaric acid in 8, and of adipic acid in 7. High-pressure liquid chromatography of urinary acylcarnitines was done in 8 patients. All 8 had a high excretion of isobutyryl, 3 of n-butyryl,1 of2-methylbutyryl,1 of isovaleryl, and 2 of acetyl carnitine. There was a carnitine deficiency in serum in 10
Gas-chromatography/mass-spectrometry
urine showed
Mspl,Sacl,Xmnl,Pstl, and Pvull refer to restriction endonucleases used (1 = major allele, 2= minor allele)
an
463—also results in the loss of an MspI site. This arginine-tocysteine mutation has been identified in both type 1 and type 3 Gaucher disease and was present in 11of 62 patients.’ If the 463 mutation were present Dahl and colleagues’ 598 bp segment of DNA would not be cleaved to 580 bp, and this subtle difference might not be appreciated on a 1-2% gel. (Incidentally, the bands in the illustration provided by Dahl et al seem to be mislabelled in respect of size.) Investigators screening for gene mutations in Gaucher’s disease should be aware of the 463 mutation. If Msp is used for screening, the laboratory should amplify a larger DNA segment, so that the presence and/or absence of both the 444 and 463 mutations can be established simultaneously. Use of the technique described by Dahl et al may lead to errors in genetic counselling when applied to a population other than the Norrbottnian Gaucher patients. Clinical Neuroscience Branch, Section of Molecular Neurogenetics, National Institute of Mental Health, Bethesda, Maryland 20892, USA
ELLEN SIDRANSKY KARA MAYSAK EDWARD I. GINNS
1 Tsuji S, Choudary PW, Martin BM, et al. A mutation in the human glucocerebrosidase gene in neuronopathic Gaucher’s disease. N Engl J Med 1987; 316: 570-75. 2. Martin BM, Sidransky E, Ginns EI. Gaucher disease: advances and challenges. Adv Pediatr 1989; 36: 277-306. 3 Hong CM, Oshashi T, Yu YJ, Weiler S, Barranger JA Sequence of two alleles responsible for Gaucher’s disease. DNA Cell Biol 1990; 9: 232-41 4. Sidransky E, Tsuji S, Stubblefield B, Martin BM, Ginns EI Current genotypic analysis does not adequately account for phenotypic variation in Gaucher patients. Vth International Congress of Inborn Errors of Metabolism; OC4 7 (abstr).
Genetic markers of familial coronary heart disease SIR,-We have reported’ that in 713 men aged 30-59 a history of coronary heart disease (CHD) before age 60 in first-degree relatives
is associated with a significantly increased frequency of CHD morbidity in those who have DNA restriction fragment length polymorphism (RLFP) markers of the apolipoprotein AI/CIII/ AIV gene cluster. The RLFP are the minor alleles (X2, M2, Pz, Sz) of four biallelic markers identified with the enzymes XmnI, MspI, PstI, and SacI, respectively. We have now examined these men for allele status at a fifth RLFP in this gene region. This region identified by PvulI is in the first intron of the Apo CIII gene. DNA stored at - 20°C was digested with PvuII and DNA fragments were separated by electrophoresis and transferred to nitrocellulose filters after denaturation. The filters were then hybridised with a labelled CIII cDNA probe (pAT/CIII/8, kindly provided by Dr C. C. Shoulders). This probe identifies a constant fragment 1 ’4 kb in length and variable fragments of 1 kb (major allele, VI) and 0,87 kb (minor allele, Vz), the allele frequencies being 0-763 and 0’237, respectively. An increased frequency of V, has been reported in patients with angiographically proven CHDIn our study Vz frequency was not increased in men with CHD; the relative CHD frequency is significantly higher in men homozygous for Vl, although only in those who have one or more of the minor alleles, Xz
M2, P2, S2 (p < 0001). The five markers
are no more
than 10 kb bases apart. Of 32 11(a-k, table). Men with
possible haplotypes we are able to identify
APO Al/Clll/AIV MARKER HAPLOTYPES
haplotypes c-h have a higher relative premature CHD frequency of 2-00 (n 278; p < 0-001). The relative frequency is higher when 2 or more first-degree relatives are affected but the numbers are small and the difference is not significant. In a logistic regression analysis neither family history on its own nor haplotypes c-h emerges as a significant co-variable of CHD morbidity, but when the two are combined the odds ratio is 2 92 (95% confidence limits 1’91-3-91; p=0016). If the variables age, social class, smoking habits, blood pressure, plasma levels of cholesterol, apolipoproteins AI and B, triglycerides, and total cholesterol/HDL cholesterol ratios are included in the analysis, the co-variate adjusted odds ratio for CHD morbidity and haplotypes c-h in men with a family history of premature CHD is 2-73 (1 72-3 73; p 0023). The higher prevalence of premature familial CHD morbidity in those with haplotypes c to h is therefore independent of other major CHD risk factors. The selective association of some marker haplotypes in the region of the AI/CIII/AIV genes with significantly higher frequencies of familial CHD morbidity supports the conclusion that liability to CHD is enhanced by variants of one or more of these genes or of their regulators. =
=
MRC Human Genetics Unit, University Department of Medicine and Department of Clinical Chemistry, Western General Hospital, Edinburgh EH4 2XU, UK
W. H. PRICE S. W. MORRIS A. H. KITCHIN P. R. WENHAM P. R. S. MCKENZIE P. M. DONALD
1. Price WH, Morris SW, Kitchin AH, Wenham PR, Burgon PRS, Donald PM. DNA restriction fragment length polymorphisms as markers of familial coronary heart disease Lancet 1989; i: 1407-11. 2. Coleman RT, Gonzalez PA, Funke H, Assmann G, Levy-Wilson B, Frossard PM. Polymorphisms in the apolipoprotein AI-CIII gene complex. Mol Biol Med 1986; 3: 213-28. 3. Frossard PM, Funke H, Coleman RT, Assmann G. Genetic markers for coronary atherosclerosis in the human apolipoprotein AI-CIII-AIV gene complex. Am J Hum Gener 1986; 39: A199.
Secondary metabolic defects in spinal muscular atrophy type II SiR,—The genetic mapping of chronic childhood-onset spinal muscular atrophy types II (intermediate) and III (KugelbergWelander disease) and of acute SMA (type I, Werdnig-Hoffmann disease) allows prenatal diagnosis in informative families (Dr Melki and colleagues, Aug 4, p 271). However, this advance does not provide the early prospect of any specific therapy for children with these diseases. Any palliative treatment should be considered. We here report metabolic studies in 14 children (6 boys, 8 girls) with SMA type 11.1 Muscle biopsy findings were typical of SMA type II. In one biopsy sample there was a mild and in another a clear increase in the lipid content of type I fibres. Every patient had a typical electromyographic neurogenic pattern. By age at metabolic study the patients could be divided into three groups: Group 1, aged 1-3 years (n=5; age at onset, birth [1 floppy infant] to 18 months). 3 children could not maintain a sitting position; 1 could not stand up when supported, and 1 could. Group 2, aged J- 5 years (n=5, age at onset, 6-18 months). These children had acquired, with a delay, a very unsteady gait. Children with SMA type II are never able to walk.’ Nonetheless the early onset and the muscle biopsy findings were typical of SMA type II. This group may represent borderline cases between SMA type II and type 111.1 Group 3, aged C-/ 7 5 years (n = 4; age at onset, 9-18 months). These children were wheelchair-bound, and had some respiratory
problems. of organic acids in abnormal excretion of ethylmalonic acid in all 14 children, of methylsuccinic acid in 9, of glutaric acid in 8, and of adipic acid in 7. High-pressure liquid chromatography of urinary acylcarnitines was done in 8 patients. All 8 had a high excretion of isobutyryl, 3 of n-butyryl,1 of2-methylbutyryl,1 of isovaleryl, and 2 of acetyl carnitine. There was a carnitine deficiency in serum in 10
Gas-chromatography/mass-spectrometry
urine showed
Mspl,Sacl,Xmnl,Pstl, and Pvull refer to restriction endonucleases used (1 = major allele, 2= minor allele)
an