Early onset myotonic dystrophy. Clinical and laboratory findings in five families and a review of the literature.

Abstract

MYOTONIC dystrophy has been well described in the adult. It is inherited as an autosomal dominant and is characterized by myotonia, muscle wasting, and often by ptosis and cataract. 1 Involvement of other organs such as the lungs, heart, gastrointestinal tract, endocrine glands, and brain has been reported. 2-6 The onset of the disease usually occurs in the second or third decade in contrast to the earlier onset in myotonia congenita (Thomsen's disease). 7 Early onset of myotonic dystrophy was first emphasized by Vanier in 1960. 8 He reported six children in whom the disease manifested in infancy as congenital hypotonia and facial diplegia. Parker subsequently 9 described a family in which eight members had evidence of the disease in childhood, two with congenital facial diplegia. Dodge et al 5 in 1965 reported their findings in seven other children who presented with a variety of clinical features. They