Background Congenital fibrosis of the extraocular muscles (CFEOM) is a rare hereditary nonprogressive disorder characterized by bilateral ptosis, with severely limited ocular motility. We report a new mutation site of KIF21A gene in a Chinese family with congenital fibrosis of the extraocular muscles type 1 (CFEOM1).
Methods We conducted a retrospective study of case series. Standard ocular examinations were performed on 10 persons in a CFEOM1 family. Next-generation sequencing (NGS) was performed to sequence 828 genes related to oculopathy. To detect mutations, we determined the splice sites of the KIF21A gene.
Results The five patients with CFEOM1 were found in the ten people of a Chinese family on three generations. A new KIF21A pathogenic SNP mutation site KIF21A-ex20 c.2821C> T (p.Arg941Trp) was identified by compared with human genome reference genes and Sanger sequencing.
Conclusions A new KIF21A pathogenic SNP mutation site KIF21A-ex20 c.2821C> T (p.Arg941Trp) may be a major disease‑causing gene for the Chinese family with CFEOM1.