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

To determine the mutation responsible for the congenital fibrosis of the extraocular muscles type I(CFEOM1) in a Chinese family. 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). 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. This Chinese family with CFEOM1 may be caused by a c.2860C to T mutation in the KIF21A gene.