Table 1

 Clinical features of families A and B

PedigreeAge (years)SexSymptomsElectrocardiogram findingsEchocardiogram findingsPhenotypic assignmentACTC genotype
* Cardiac catherisation showed apical systolic obstruction and normal left ventricular function and coronary arteries.
A
    II-151ManAnginaAtrial fibrillationHCMHCMTyr166Cys
Dyspnoea (New York Heart Association grade III)Septum 18 mm Systolic anterior movement of mitral valve Left ventricle outflow tract gradient at rest 35 mm Hg
    III-127ManNoIncomplete right bundle branch blockHCMHCMTyr166Cys
Septum 15 mm
    III-224ManNoIncomplete right bundle branch block and right axis deviationNormalSuspected HCMTyr166Cys
    II-3  47ManNoIncomplete right bundle branch block and right axis deviationNormalSuspected HCMTyr166Cys
B
    I-161ManAnginaAtrial fibrillationNot obtainable*HCMMet305Leu
Dyspnoea (New York Heart Association grade II)