中国人遗传性并指畸形家系HOXD13基因突变鉴定

目的:研究一个中国人并指(趾)畸形(synpolydactyly,SPD)家系,检测家系成员中是否存在同源盒D13 基因(homeobox D13,HOXD13 )突变.方法:采集SPD 患者及其家系成员的外周血,提取基因组DNA,设计针对HOXD13 基因特异性引物,进行PCR 扩增,产物经2%琼脂糖凝胶电泳检测,并进行测序鉴定.结果:本家系3代共23人, 6人患病,研究发现患者HOXD13 基因第一个外显子中多聚丙氨酸链由15个延长至22个,第二个外显子基因序列正常.结论:首次揭示中国人并指(趾)畸形家系HOXD13 基因存在多聚丙氨酸延展增加7个丙氨酸的突变形式,表明一定数目的丙氨酸延展可能是导致并指(趾)畸形的重要因素.

Identification of a recurrent mutation in the HOXD13 gene in a Chinese family with synpolydactyly

Objective: To detail the clinical findings in a consanguineous Chinese family,and to identify homeobox D13(HOXD13)gene mutation of the affected individuals in a Chinese synpolydactyly(SPD)kindred.Methods: The genomic DNA was extracted from the peripheral blood samples of SPD family members.With the use of a pair of sepecific primers,exon1 and exon2 of HOXD13 were emplified by polymerase chain reaction(PCR).All the amplified fragments were electrophoresed on 2% agarose gels,and the purified PCR products of normal and mutant alleles were cloned and sequenced.Results: The kindred including 23 members and 6 get affected.Genomic DNA was extracted from 5 affected family members,a fragment of 291bp was amplified by PCR to cover the imperfect GCG triplet repeat sequence in exon 1 of HOXD13 encoding the 7-residue polyalanine tract,the exon 2 has no such mutation.Conclusion: We first reaveal that HOXD13 encodes additional 7-residue polyalanine expansion in a consanguineous Chinese family which suggest that synpolydactyly may result from polyalanine expansion in HOXD13.