Menkes Disease and Other ATP7A Disorders

Mutation of the copper ATPase ATP7A, located in the trans-Golgi network and encoded by the X chromosome, causes the progressive copper deficiency disorder Menkes disease (also known as kinky hair disease), in addition to occipital horn syndrome and ATP7A-related distal motor neuropathy. The fundamental abnormality in this disease is thus the maldistribution of copper, which is unavailable as a cofactor of several enzymes including mitochondrial cytochrome c oxidase, lysyl oxidase, superoxide dismutase, dopamine β-hydroxylase and tyrosinase. Thus, the main features of Menkes disease include mitochondrial respiratory chain dysfunction (complex IV deficiency), deficiency of collagen cross-links resulting in hair (pili torti and trichorrhexis nodosa) and vascular abnormalities (elongated cerebral vessels and subdural effusions), neuronal degeneration (markedly affecting Purkinje cells), and deficient melanin production which dominate the disease manifestations. Affected neonates present with hypothermia, feeding difficulties, and seizures. The infants are pale and exhibit kinky hair. A variety of minimally symptomatic phenotypes, including ataxia or mental retardation, have been recognized.