Among Hh family members, loss of sonic hedgehog (SHH) function results in pathologies as diverse as holoprosencephaly [44] or preaxial polydactyly [45], whereas mutations in indian hedgehog (IHH) lead to bone growth defects (brachydactyly or acrocapitofemoral dysplasia) [46]. This evidence concerns the gene SHH and brachydactyly.