Mapping And Analysis Of Disease Gene For Two Chinese Pedigree With Hand And Foot Malformation

Objective Split hand/split foot malformation (SHFM) is a congenital limb developmental disorder, which impairs the fine activities of hand/foot in the affected individuals seriously. We encounter two Chinese families with autosomal dominant SHFM and try to identify the disease-causing genetic aberration and underlying pathogenesis of SHFM. Providing genetic counseling and prenatal diagnostic services for patients and family members.Methods Peripheral blood samples were collected from two Chinese SHFM families, including 15 members of the five-generation family 1 and 8 members of family 2. Part of exons and their flanking intronic sequences of the TP63 gene were amplified and sequenced directly. We performed the gene scan and linkage analysis using microsatellite markers around the 4 known SHFM loci and the genome-wide linkage analysis using the SNPs Array HumanLinkage-12 (Illumina) respectively in family 1. The HumanHap550 Genotyping SNPs array was employed for copy number analysis of the two prodands. Finally, we performed the quantitative PCR essays to verify the tandem duplication on the chromosome 10q24.3 in all affected individuals of the family 1. We provided prenatal diagnosis for the family 1 using linkage analysis.Results No mutation was identified in the TP63 gene in the prodands. Linkage analysis using microsatellite markers located on the 4 known loci of SHFM demonstrated two-point LOD scores <1.0. However, the genomewide linkage analysis by SNP Genotyping provided significant evidence for 1 susceptibility locus (multipoint LOD 3.01) on chromosome 10q24.2-q25.1. The SNPs array copy number analysis found a duplication spanning 420,860 bp (chrl0:102969197-103390056) on chromosome 10q24.3 of family 1 and a duplication spanning 591,068 bp (chrl0:102887047-103478114) on chromosome 10q24.3 of family 2. The affected individuals of family 1 were all confirmed carrying the same tandem duplication by quantitative PCR. The fetus inherited the pathogenic haplotype of the prodand through Haplotype analysis. type-B ultrasonic conformed the fetus with hand and foot malformation.Conclusion1. Established the method of genome-wide scan and linkage analysis in mapping and identification of the disease gene using SNPs Array.2. Identify the pathopoiesis of the two SFHM families, The duplication at chromosome 10q24.3 causes split hand/split foot malformation (SHFM) in the two Chinese families.3. Providing accurate information of genetic counseling and prenatal diagnosis for the two families. Successful implementation of prenatal diagnosis to family 1, avoiding the birth of affected children.