A de novo heterozygous variant in the SON gene is associated with Zhu-Tokita-Takenouchi-Kim syndrome

Abstract

Background: Zhu-Tokita-Takenouchi-Kim (ZTTK, OMIM# 617140) syndrome is a rare, autosomal dominant genetic disorder caused by heterozygous variants in the SON gene (OMIM#182465, GenBank#NC_000021.9). There are only 33 cases and 26 causative SON variants reported to date since the first report in 2015. Here, we report a new case of ZTTK syndrome and a de novo disease-causing SON variant.

Methods: We conducted whole-exome sequencing (WES) to obtain genetic data of the patient. The clinical and genetic data of the patient were analyzed.

Results: The clinical features of our patient were strikingly similar to previously reported cases. Notably, our patient had unique presentations, including a bridged palmar crease in the left hand and growth hormone deficiency. The c.5297del de novo variant in SON causes an amino change (p.Ser1766Leufs*7).

Conclusion: Our report expands the mutant spectrum of the SON gene and refines the genotype-phenotype map of ZTTK syndrome. Our findings also highlighted the importance of WES for early diagnosis of ZTTK syndrome, which may improve diagnostic procedures for affected individuals.