Occipital horn syndrome (OHS) is a mild form of Menkes disease (MD), a syndrome characterized by progressive neurodegeneration and connective tissue disorders due to a copper transport defect. The disease is Monarch Disease Ontology identifier MONDO_0010572 (occipital horn syndrome). Also known as: EDS IX, Ehlers-Danlos syndrome type 9, Ehlers-Danlos syndrome type IX, X-linked cutis laxa, occipital horn syndrome, X-linked recessive.