Sotos syndrome: A study of antenatal presentation

To determine the fetal ultrasound findings associated with Sotos syndrome caused by deletions at 5q35 including the NSD1 and a point mutation in this gene.

This was a retrospective study of eight pregnancies with fetal Sotos syndrome identified by chromosomal microarray (CMA)/whole exome sequencing (WES). Clinical and laboratory data were collected and reviewed for these cases.

Two cases had no significant fetal abnormalities, and were only diagnosed after birth. One case presented in the first trimester with increased nuchal translucency. The remaining five fetuses were identified at late gestation. One of the five fetuses presented in the second trimester with mild ventriculomegaly, and four in the third trimester with mild ventriculomegaly, macrocephaly and polyhydramnios. CMA was done on all cases and revealed 5q35 deletions in seven cases, and WES detected a maternally inherited NSD1 variant in one case.

The fetal ultrasound findings in cases with Sotos syndrome, associated with deletions at 5q35 and a point mutation in the NSD1 are not specific with the most common finding being mild ventriculomegaly.