[Clinical and genetic aspects of the early form of Steinert's dystrophia myotonica].

Observations relating to 18 cases of the neonatal form of myotonic dystrophy are described. These consisted of 9 cases of severe forms incompatible with survival, characterised by major respiratory disorders, hypotrophia and difficulty in swallowing, associated with a facial diplegia and pes equinus. The other 9 patients suffered from more moderate, not lethal forms. In addition to muscular troubles manifested by precocious hypotonia, the disease involved serious mental retardation. The absence of myotonia was constant in the very young infants. Anomalies in pregnancies resulting in the birth of children suffering from a neonatal form of myotonic dystrophy are analysed and their frequency is emphasized. From the genetic point of view, the elective transmission of myotonic dystrophy by the mothers was found in all the cases. The knowledge of neonatal forms must be taken into consideration for genetic counseling.