Among these families, KIF21A c.2860C > T (p.R954W) (63.6%), c.2861G > A (p.R954Q) (11.9%), c.2861G > T (p.R954L) (3.4%) were the most commonly identified mutations, suggesting R954 mutations served as hotspot mutation of KIF21A. Therefore, R954 mutations could be screened first in the etiological investigation of CFEOM1 individuals in the future, instead of conducting experiments on whole exons of KIF21A for higher efficacy. The gene discussed is KIF21A; the disease is congenital fibrosis of extraocular muscles.