A Missense Mutation in the β-Myosin Heavy Chain Gene in a Japanese Patient With Hypertrophic Cardiomyopathy

Abstract

A 55-year-old man had been previously admitted at the age of 44 because of chest pain on effort. He was diagnosed as hypertrophic obstructive cardiomyopathy with a left ventrlcular outflow pressure gradient of 65 mmHg. We analyzed the cardiac β-myosin heavy chain gene in this patient using polymerase chain reaction-single strand conformation polymorphism analysis (PCR-SSCP analysis). PCR-SSCP analysis revealed a sequence variation within exon 16. A G-to-A transversion with replacement of Val by Met at codon 606 was confirmed by sequencing analysis. Previously, a ⁶⁰⁶Val⇾Met mutation has been reported to give a benign prognosis because of the neutral charge substitution. However, there have been some premature deaths in this patient's kindred. Thus, despite the absence of a change in charge, this mutation may be malignant in some kindreds.