Occipital horn syndrome

Occipital horn syndrome, formerly considered a variant of Ehlers-Danlos syndrome, is an X-linked recessive mitochondrial and connective tissue disorder. It results from a deficiency in the transport of the essential mineral copper, associated with mutations in the ATP7A gene, and represents a milder form of Menkes disease with later onset and reduced neurological damage. Notable features include bone deformities, specifically bony projections on the back of the skull that give the condition its name, along with malformations of the joints. Affected children typically present with loose, elastic skin, joint hypermobility, and various complications including chronic diarrhea, neurological dysfunction, and reduced levels of copper-binding protein in the blood.