Localization of the syndactyly type II (synpolydactyly) locus to 2q31 region and identification of tight linkage to HOXD8 intragenic marker

Abstract

Syndactyly type II (SynPolyDactyly; SPD) is an autosomal dominant condition with incomplete penetrance and variable expressivity. Sixty-two meioses from a kindred with 425 individuals were used to map the SPD locus to 2q31 region, approximately 1.7 cM (Lod score = 12.96) centromeric to HOXD8 intragenic marker. Other homeobox-containing genes in this region have previously been ordered as cen-DLX1/ DLX2-EVX2-(5'→HOXD13..HOXD8..HOXD1-→3')-tel. A single recombinant with HOXD8 excluded the most 3' end of HOXD cluster as a candidate site for SPD, but a mutation in the 5' end of HOXD cluster, especially in HOXD13, EVX2 or DLX2/DLX1, may still be responsible for this phenotype. An updated order of D2S142-D2S111 - (D2S335/D2S333) - D2S326 - D2S1238 - SPD -(HOXD8/D2S1244) - (D2S300/D2S138) - D2S148 - D2S324 -D2S1384-D2S434 was deduced from meiotic recombination events.