[Genetic analysis of two families with Short-rib thoracic dysplasia type 3].

OBJECTIVE

To explore the pathogenic variants and clinical classification of two fetuses with Short-rib thoracic dysplasia with or without polydactyly (SRTD).

METHODS

With informed consent obtained, the phenotypic characteristics of the fetuses were comprehensively examined, and genomic DNA was extracted from fetal skin tissue and peripheral blood samples of the parents with conventional phenol-chloroform method. Whole exome sequencing (WES) was carried out on both fetuses, and the candidate variants were validated by Sanger sequencing. The pathogenicity of the candidate variants was analyzed using bioinformatic software VarCards, and the impact of the variants on the protein structure was predicted with Swiss-Pdb-viewer.

RESULTS

Both fetuses were found to harbor compound heterozygous variants of the DYNC2H1 gene, including c.515C>A (p.Pro172Gln) and c.5983G>A (p.Ala1995Thr) in fetus 1, and c.5920G>T (pGly1974) and c.9908T>C (p.He3303Thr) in fetus 2. The parents of both fetuses were heterozygous carriers.

CONCLUSION

The compound heterozygous variants of the DYNC2H1 gene probably underlay the SRTD3 in the two fetuses.