HOXA13 and hand-foot-genital syndrome: HFGS is characterised by fully penetrant limb abnormalities and incompletely penetrant urogenital defects and is caused by heterozygous mutations in HOXA13. The original basis for investigating HOXA13 as a candidate gene for HFGS was the identification of a spontaneous frameshifting deletion in Hoxa13 exon 1 of the Hypodactyly mouse [11].