1 research outputs found
Epidemiology and genetics of hypertrophic cardiomyopathy
Background: Hypertrophic cardiomyopathy (HCM) is a heart muscle
disorder and is known to be inherited as an autosomal dominant trait.
Mutations in several sarcomeric, cytoskeletal and mitochondrial genes
have been reported in HCM. Though many cases of HCM are being
identified, there is limited data regarding the epidemiology and
genetics of HCM in India. Aim: Therefore the present study is
envisaged at identifying the epidemiological variables in HCM and
fitting a probability model assuming dominant mode of inheritance in
HCM, which may in turn shed light on the heterogeneity of this complex
disorder. Materials AND Methods: The 127 HCM cases were divided into
subtypes based on pattern of hypertrophy. Chi square analysis, odds
ratio, probability, relative frequency, penetrance and heritability
estimates were calculated apart from epidemiological variables.
Results: The HCM subtypes revealed the heterogeneous nature of the
condition suggesting that the genes/mutations involved in their
pathogenesis are different and this is supported by distinctive
differences observed in their probability, heritability and penetrance
estimates apart from epidemiological variables. An increased male
preponderance was observed with the sex ratio being 3.7:1. The age at
onset was found to be more than a decade early in familial cases (30
± 10 yrs) compared to non familial cases (44 ± 14 yrs). Chi
square analysis revealed obstructive HCM to be following autosomal
dominant mode of inheritance where as non-obstructive HCM was
significantly deviating. The level of deviation was significantly high
for the middle onset group compared to early and late onset groups,
therefore this group may be considered as an admixture wherein
genes/gene modifiers and environmental variables may be contributing to
the heterogeneity and this is further supported by odds ratio.
Conclusions: The study thus brings out the complexity of HCM and
suggests that modes of inheritance other than autosomal dominant may be
encountered in a subset of HCM especially in asymmetric septal
hypertrophy, apical, concentric and mid cavity obstruction subsets and
hence a mixed model of inheritance is the best fit for such complex
disorders