Single-strand conformation polymorphism analysis on the δ-sarcoglycan gene in Japanese patients with hypertrophic cardiomyopathy

To elucidate the etiology of hypertrophic cardiomyopathy (HC) in humans, we analyzed the δ-sarcoglycan gene (SG), which is reported to be the causal gene for HC in the Syrian hamster BIO14.6. We performed polymerase chain reaction (PCR) single-strand conformation polymorphism (SSCP) and nucleotide sequence analyses on the δ-SG in 102 patients with HC. SSCP was detected in exon 2 of the gene, but not in the other exons. The direct sequencing analysis of exon 2 revealed a C→T substitution at nucleotide residue 84 (TAC→TAT) with no amino acid alteration (Tyr→Tyr). There were no significant differences in allele frequencies of C/T between the patients with HC and the control group. Patients with HC were classified into 4 subgroups: obstructive HC, nonobstructive HC, apical HC, and familial HC. The allele frequency of C/T polymorphism in each of these groups was compared with that of the control group. The obstructive HC group showed a significantly greater frequency of the allele T than in the control group (31.6% vs 15.1%, RR = 2.6, p = 0.023). No other significant differences were observed. Thus, amino acid alteration in δ-SG may not be a common cause of HC in Japanese patients.