A possible heterozygous advantage in muscular dystrophy.

In certain autosomal recessive disorders there is suggestive evidence that heterozygous carriers may have some selective advantage over normal homozygotes. These include, for example, cystic fibrosis, Tay-Sachs disease and phenylketonuria. The best example so far, however, is that of significant heterozygous advantage in sickle-cell anaemia with increased resistance to falciparum malaria.