FAMILY OF MYOTONIC DYSTROPHY - A CASE REPORT

Myotonic dystrophy (DM) is a clinically and genetically heterogeneous disorder. There are two major forms namely DM1 (for a century known as Steinert's disease) and DM2, recognized in 1994 as a milder version of DM1.The prevalence of DM is 1 in 8000 in the general population, but the proportions of myotonic dystrophy caused by DM1 and DM2 are unknown.These autosomal dominant conditions are among the most common forms of adult-onset muscular dystrophy. However, it is more than simply a muscular dystrophy per se, since affected individuals may show cataracts, cardiac conduction abnormalities, infertility, and insulin resistance. Furthermore, there is a severe congenital form of DM1 with marked developmental disability.The genetic disease is one of the best examples for a phenomenon called 'anticipation' in which the age of onset of the disease is early and the disease severity is greater in the successive generations.One consequence of the multi-systemic nature of this disorder is that individuals affected by DM1 or DM2 may first present to internists, cardiologists, ophthalmologists, endocrinologists, and pediatricians (in the case of DM1), before they see a neurologist. We present a classic case of a family of myotonic dystrophy,from the southern districts of Tamilnadu, with the phenomenon of genetic anticipation in this article