ABSTRACT
Objective To explore the distribution of exon mutations of CDX1 gene in children with congenital anorectal malformation (ARM).Methods In a case-control study conducted between June 2003 and March 2009,108 children with congenital ARM and 120 normal children undergoing health examinations who were admitted to the Shengjing Hospital of China Medical University (85 children with congenital ARM and 60 normal children) and the Affiliated Hospital of Hebei University (23 children with congenital ARM and 60 normal children) were assigned to the case group and the control group,respectively.PCR was performed to extend exons of the CDX1 gene and then sequence analysis was conducted after genomic DNAs were extracted from the peripheral blood.Categorical data with normal distribution were presented as (x) ± s and analyzed using the t test,count data were analyzed using the chi-square test.Results Exon sequencing was performed in the case group.Four children with 4 mutations of CDX1 located at coding regions were detected,including 1 with archostegnosis,1 with rectoperineal fistula,1 with rectovestibular fistula and 1 with rectourethral fistula.Four mutations located at the highly conserved homology domain of the CDX1 gene.The mutations of 1 child located at exon 1 of CDX1 gene (c.213-214Ins GAA).The mutations of 2 children located at the splicing region to exon 3 of the CDX1 gene (c.6G ＞ C,c.27G ＞ T).The mutations of 1 child located at the idiocratic splicing region to exon 3 of the CDX1 gene(c.18A ＞ C).No mutation was detected in the controls.Mutations of the CDX1 gene at c.213-214Ins GAA,c.6G ＞ C,c.27G ＞ T,and c.18A ＞ C,respectively,resulted in amino acid substitutions at 96-98Ins E,K199N,R206S,and Q203H in the protein.Conclusion Exon 1 or 3 mutations of the CDX1 gene is identified in children with congenital ARM,and CDX1 gene may be a susceptibility gene for ARM.