Hajdu-Cheney syndrome (HCS) is a rare, heritable disorder of connective tissue; only about 50 cases have been reported in the medical literature. The breakdown of bone (osteolysis), especially the outermost bones of the fingers and toes (acroosteo...

Xeroderma pigmentosum (XP) is a group of rare inherited skin disorders characterized by a heightened reaction to sunlight (photosensitivity) with skin blistering occurring after exposure to the sun. In some cases, pain and blistering may occur imm...