Figure 1. Pedigree and genetic analysis of the family with congenital fibrosis of extraocular muscles. A: Family pedigree shows that all three siblings have congenital fibrosis of extraocular muscles (CFEOM) while both parents are asymptomatic. Haplotype analyses using the four microsatellite markers (D12S331, D12S1048, D12S1668, and D12S2194) flanking the kinesin family member 21A (KIF21A) gene denote the affected haplotype (black bar) shared by all patients and their mother. Genotyping data for each marker involved the size of the products of the polymerase chain reaction (PCR). The dashed arrow indicates possible maternal germline mosaicism. Black filled symbols and blank symbols represent affected and unaffected status, respectively. B: The DNA chromatogram sequence for the KIF21A gene shows the three affected siblings are heterozygous for the c.2860G>T mutation, and their parents were homozygous for the wild-type allele. The arrow points to the site of the base substitution. C: The missense mutation KIF21A p.R954W was evolutionarily conserved among various species.