[Sotos syndrome: a novel nonsense mutation in NSD1 gene, presenting with neonatal cutis laxa].

Sotos syndrome is an overgrowth condition characterized by facial gestalt, macrocephaly, excessive height, and different degrees of developmental delay. We report the case of a 20-month-old boy with a confirmatory molecular study, showing a novel nonsense mutation in NSD1 gene, presenting cutis laxa as the main phenotypic trait in the neonatal period. This association has been previously described in 3 patients with a clinical diagnosis of Sotos syndrome, without confirmatory molecular analysis. Our patient was tested for congenital disorders of glycosilation as part of the cutis laxa differential diagnosis. During the postnatal follow-up period the head circumference and height became greater than 97(th) percentile (having been close to the 50(th) in the newborn period). These facts and the progressive development of characteristic phenotypic features of Sotos syndrome during the first months of life gave us the clue for the clinical diagnosis and the molecular investigation.