The proband had microduplication in the chromosomal region containing NSD1, which resulted in a Sotos syndrome reversed phenotype, and this duplication was associated with microcephaly, short stature, and developmental delay.
Sotos syndrome is a childhood overgrowth syndrome characterized clinically by a distinctive facial gestalt, advanced bone age, childhood overgrowth, and non-progressive developmental delay; and genetically by haploinsufficiency of the Nuclear receptor binding SET Domain 1 (NSD1) gene.
We report on a girl with developmental delay and a de novo 264 kb interstitial duplication in the region of Sotos syndrome at 5q35.3 in the immediate vicinity of critical NSD1 gene, but manifesting the phenotype, of overgrowth both prenatal stage and postnatal, macrocephaly, developmental delay, and resembling that of Sotos syndrome, rather than the recently reported syndrome of reciprocal duplication.