[Clinical and molecular genetic analyses of congenital myotonic dystrophy]

Myotonic dystrophy (DM) results from the amplification of an unstable CTG repeat in the 3' untranslated region of a transcript encoding an MtPK. Infants with congenital DM are shown to have on average a greater amplification of the CTG repeat than is seen in the noncongenital DM patients. The major clinical features of congenital DM are bilateral facial weakness, hypotonia, feeding difficulties, respiratory distress, delayed motor development and mental retardation. We present 6 patients, aged 11-35 years, from unrelated 5 families with clinical symptoms of congenital DM. The four of the patients were inherited paternally and only one showed a reduction in the CTG repeat size.