Human mutations in these putative interaction partners have been found to cause specific genetic syndromes including Myhre syndrome (OMIM#139210, SMAD4 variants), Hand-foot-genital syndrome (OMIM#140000, HOXA13 mutations) or Nail-patella syndrome (OMIM#161200, LMX1B dysfunction) and congenital malformation involving the skeleton, eye, genitals, kidney, heart and brain (BMP2, PAX6, MEIS2). Here, SMAD4 is linked to nail-patella syndrome.