Split hand/foot malformation (SHFM) is a congenital limb disorder resulting in the absence of fingers or toes, deep clefts in the center of the hand or foot giving a ‘lobster claw’ like appearance, and syndactyly. The condition is highly variable even between affected members of the same family. The overall prevalence of SHFM is about 1 in 18,000 live births, however SHFM6 is a rare subset with only a handful of cases reported thus far.
The disorder follows an autosomal recessive pattern of inheritance and is caused by homozygous mutations in the WNT10B gene. This gene encodes a secreted signaling protein that mediates the canonical Wnt signaling pathway and thereby plays a role in several developmental processes, including regulation of adipocyte, chondrocyte and epithelial cell differentiation, skeletal muscle fiber development and bone trabecula formation.