This mutant allele is not the first hypomorphic allele of atp7a. A less severe form of Menkes disease, Occipital Horn Syndrome, is also caused by mutations in atp7a. Children with this disease have many clinical problems similar to Menkes disease; however, as this syndrome is not fatal in early life other abnormalities can be appreciated including skeletal defects such as deforming hyperostosis and kyphoscoliosis [32]. Here, ATP7A is linked to Menkes disease.