[Genetic analysis of a Chinese pedigree with split hand and foot malformation]

To analyze the clinical manefestation and genetic basis of split hand and foot malformation (SHFM) in a Chinese pedigree.

The affected people in the family were checked by X-rays. Eighteen patients provided their peripheral blood, and the genomic DNA of the samples was extracted. The linkage and haplotype analysis were carried out using the microsatellite markers, and the limb malformation related gene Dactylin (DAC) including the coding region, exon-intron boundaries and part of promoter region was sequenced.

Most members of the family with the disease phenotype showed absence or hypoplasia of the index finger, and absence or 3-4 syndactyly of the middle finger. The degree of abnormality in feet was severer than that in hands. All phenotypes of the patients display the basic characters of SHFM. Since the maximum two point LOD score of the D10S192 was 3.50 (theta=0.00), the SHFM in this pedigree can be categorized to the SHFM3. The haplotype analysis of recombination events revealed the candidate locus to a 21cM region between D10S185 and D10S1693. No mutation was found by the sequencing result of DAC gene.

Through the analysis of phenotype of the patients, the typical SHFM disease can be confirmed. The linkage and haplotype analysis demonstrated that the 21cM region in 10q23-q26 locus was the major cause to the disease in this pedigree. The mutation of DAC gene can be excluded from cause of SHFM3 phenotype.