has material basis in germline mutation in NRAS nervous system benign neoplasm melanocytic nevus neurocutaneous melanocytosis https://github.com/monarch-initiative/mondo/issues/4521 https://github.com/monarch-initiative/mondo/issues/8567 https://www.malacards.org/card/melanosis_neurocutaneous MEDGEN:154259 GARD:0007186 OMIM:249400 melanosis, neurocutaneous 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. UMLS:C0544862 Orphanet:2481 neurocutaneous melanosis MONDO:0009578 NCMS NCM MESH:C537387 icd11.foundation:403221860 NANDO:2200827 NCIT:C175215 neurocutaneous melanosis syndrome neurocutaneous melanosis, somatic neurocutaneous syndrome hereditary skin disorder hereditary neurological disease