Osio et al. (2007) studied a black family in which 6 individuals over 3 generations, including a pair of dizygotic twins, had hypertrophic cardiomyopathy. The index case presented at 12 years of age with symptoms of diastolic heart ... Osio et al. (2007) studied a black family in which 6 individuals over 3 generations, including a pair of dizygotic twins, had hypertrophic cardiomyopathy. The index case presented at 12 years of age with symptoms of diastolic heart failure and episodes of syncope. She had severe left ventricular hypertrophy (LVH) with a septal thickness of 3.2 cm, atrial fibrillation, and runs of ventricular tachycardia. At 36 years of age, she had left bundle branch block and had undergone implantation of a permanent pacemaker and an automatic internal cardioverter-defibrillator. Her 62-year-old mother had borderline LVH with normal sinus rhythm, and her 27-year-old sister and 42-year-old twin male cousins had LVH and normal sinus rhythm with repolarization abnormalities. The dizygotic twin brothers also exhibited different degrees of asymmetric septal hypertrophy, which the authors suggested might reflect the effects of modifier genes and environmental factors. Osio et al. (2007) noted that affected family members had normal skeletal muscle strength on physical examination, but that subclinical abnormalities might exist.
In 6 affected individuals from a 3-generation black family segregating autosomal dominant CMH mapping to chromosome 4q26-q27, Osio et al. (2007) identified heterozygosity for a missense mutation in the candidate gene MYOZ2 (605602.0001). The mutation was not found ... In 6 affected individuals from a 3-generation black family segregating autosomal dominant CMH mapping to chromosome 4q26-q27, Osio et al. (2007) identified heterozygosity for a missense mutation in the candidate gene MYOZ2 (605602.0001). The mutation was not found in 4 clinically normal family members or in 658 controls who were asymptomatic and had normal electrocardiograms and echocardiograms, including 253 black individuals. Analysis of MYOZ2 in 516 additional CMH probands revealed another heterozygous missense mutation (605602.0002) in a white proband who had 2 deceased sibs with CMH; this mutation was not found in 517 controls, including 405 white individuals.