Sotos syndrome with a novel mutation in the NSD1 gene associated with congenital hypothyroidism

Childhood overgrowth syndromes are relatively rare. A generalized overgrowth syndrome should be suspected when tall stature and macrocephaly are present, after ruling out nutritional excess and endocrinopathies. Sotos syndrome is a well-described overgrowth syndrome due to haploinsufficiency of the NSD1 gene. We present a case of an infant with permanent congenital hypothyroidism, who had tall stature and macrocephaly by 7 months of age. He was noted to have typical facial features, mild gross motor and speech delay, and scoliosis by 13 months of age. Gene sequencing revealed a heterozygous novel c6076_6087del12: p.Asn2026_Thr2029del variant in exon 20 of the NSD1 gene, pathogenic for Sotos syndrome. Congenital hypothyroidism with Sotos syndrome has been infrequently reported and may expand the spectrum of disease characteristics. Early diagnosis of overgrowth syndromes is important for developmental follow up and multidisciplinary care coordination.