Abstract

Type I myotonic dystrophy or Steinert's disease (DM1, OMIM 160900), is an autosomal dominant mulsystem disease of variable expresión caused by a (CTG)n, expansion mutation in the gene encoding for the myotonic dystrophy protein kinase (DMPK) in 19ql3. The disease is characterized by a phenomenon of anticipation, resulting in a more severe expression of the disease in successive generations, in correlation with the size of the triplet expansion. The congenital form of the disease, ussually of maternal transmisión, may cause polyhidramnios, foetal or neonatal death, or a sever neonatal floppy infant syndrome charaterized by facial diplegia, dysphagia, respiratory distress syndrome and a variable degree of mental retardation in 60% of the cases. The aim of this report is to describe a DM1 affecting a 35 years old woman and her fetus of 28 weeks of gestation at the moment of diagnosis. We describe the evolution of the pregnancy and her neonate, we discuss the reciprocal influence between pregnancy and the disease, enhacing the antenatal and neonatal complications.