Leber congenital amaurosis 9 (MONDO_0012056, a Monarch Disease Ontology term) is any Leber congenital amaurosis in which the cause of the disease is a mutation in the NMNAT1 gene. Also known as: LCA9, Leber congenital amaurosis caused by mutation in NMNAT1, Leber congenital amaurosis type 9, NMNAT1 Leber congenital amaurosis.