Mondo Description Neurocutaneous melanocytosis (NCM) is a rare congenital neurological disorder characterized by abnormal aggregations of nevomelanocytes within the central nervous system (leptomeningeal melanocytosis) associated with large or giant congenital melanocytic nevi (CMN). NCM can be asymptomatic or present as variably severe and progressive neurological impairment, sometimes resulting in death.

Uniprot Description A rare congenital disease characterized by the presence of giant or multiple melanocytic nevi on the skin, foci of melanin-producing cells within the brain parenchyma, and infiltration of leptomeninges by abnormal melanin deposits. Neurologic abnormalities include seizures, hydrocephalus, arachnoid cysts, tumors, and syringomyelia. Some patients may develop malignant melanoma.