OBJECTIVETo explore the genetic etiology of three families affected with split-hand/split-foot malformation (SHFM).

METHODSPeripheral venous blood samples from 21 members of pedigree 1, 2 members of pedigree 2, and 2 members of pedigree 3 were collected. PCR-Sanger sequencing, microarray chip, fluorescence in situ hybridization (FISH), real-time PCR, and next-generation sequencing were employed to screen the mutations in the 3 families. The effect of the identified mutations on the finger (toe) abnormality were also explored.

RESULTSMicroarray and real-time PCR analysis has identified a duplication in all patients from pedigrees 1 and 3, which have spanned FKSG40, TLX1, LBX1, BTRC, POLL and FBXW4 (exons 6-9) and LBX1, BTRC, POLL and FBXW4 (exons 6-9) genes, respectively. A missense mutation of the TP63 gene, namely c.692A>G (p.Tyr231Cys), was found in two patients from pedigree 2. FISH analysis of chromosome 10 showed that the rearrangement could fita tandem duplication model. However, next-generation sequencing did not identify the breakpoint.

CONCLUSIONThe genetic etiology for three families affected with SHFM have been identified, which has provideda basis for genetic counseling and guidance for reproduction.