[Epidemiological study of Steinert's congenital myotonic dystrophy: dysmorphological characteristics]. / Estudio epidemiológico de la distrofia miotónica congénita de Steinert: características dismorfológicas.

OBJECTIVE: Steinert's congenital myotonic dystrophy (CMD) is a systemic disease with autosomal mother-to-child transmission and characterized by generalized hypotonia, areflexia, facial diplegia, respiratory and alimentary diseases, arthrogryposis, polyhydramnios, etc. We present the study of the clinical and epidemiological characteristics of Steinert's CMD in our population, with special attention to its dysmorphological features. PATIENTS AND METHODS: In this study we present the analysis of 12 cases of Steinert's CMD identified among 26,956 infants with congenital defects registered by the Spanish Collaborative Study of Congenital Malformations (ECEMC) between April 1976 and March 1998. RESULTS: The minimum estimation of the prevalence in our population is 0.08 per 10,000 live births. We have epidemiologically observed in newborns with Steinert's CMD the presence of a statistically significant difference in the following variables: lower gestational age and birth weight, more polyhydramnios, more feet presentations and Cesarean sections, and a higher frequency of similar congenital defects in first degree relatives. The congenital defects most frequently associated to our population of CMD are located in the extremities, the head and face. CONCLUSIONS: It is important to recognize the congenital defects associated with neuromuscular disorders in the neonatal period, and particularly, the wide spectrum of Steinert's CMD that results in a fetal hypokinesia deformation sequence.