FAMILY OF MYOTONIC DYSTROPHY - A CASE REPORT

Abstract

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.