Mutation analysis of KIF21A gene in a Chinese family with congenital fibrosis of the extraocular muscles type I

Objective: To determine the mutation responsible for the congenital fibrosis of the extraocular muscles type I(CFEOM1) in a Chinese family.

Methods: Direct sequencing of exons 20 and 21 in the KIF21A gene was performed for the proband. The mutation c.2860C to T in exon 21 was examined by allele specific-PCR (AS-PCR) analysis in other family members. Haplotype analysis was performed using four STR markers (D12S1668, D12S2194, D12S331 and D12S1048).

Results: A heterozygous mutation c.2860C to T in the KIF21A gene was identified in all three affected members with CFEOM1. Haplotype analysis suggested that the mutation might derive from maternal germline mosaicism.

Conclusions: This Chinese family with CFEOM1 may be caused by a c.2860C to T mutation in the KIF21A gene.