A specific syndrome, in which hypertrophic cardiomyopathy (HCM) was associated with congenital deaf-mutism, was reported in 1987 by our team (Csanády et al, Eur Heart J, 1987). In the deaf-mute proband, HCM was diagnosed at age 26. The first family screening at that time revealed that three of the paternal uncles also manifested the disease, with congenital deaf-mutism in one. During the 27-year-long follow up, HCM developed in three brothers of the proband, with marked cochlear hearing loss in one of them, and two sudden cardiac deaths occurred. The family underwent detailed genetic analysis which included the mutation screening of the major sarcomeric genes and the unconventional myosin 6 gene (MYO6). A G/A transition at the first position of intron 7 was detected. The mutation presumably leads to addition of an abnormal amino acid after the last normal arginine in position 273 (Arg273+1X) and also activates a cryptic stop codon. The latter supposedly leads to the truncation of the distal part of the protein. The mutation was present in all the HCM phenotype positive family members. In addition three phenotype negative gene carriers were identified.
Keywords: hypertrophic cardiomyopathy, congenital deaf-mutism, molecular genetic examinations, myosin binding protein C