Falk et al, Chiang et al, Perrault et al, Koenekopp et al are reporting independently in Nat Genetics the identification of NMNAT1 as cause for an autosomal recessive form Leber Congenital Amaurosis(LCA) and all individuals with NMNAT1 mutations also had macular colobomas, due to severe degenerationÂ of the central retina. NMNAT1 is the gene linked to the LCA9 locus. NMNAT1 is the nuclear isoform of nicotinamide mononucleotide adenylyltransferase and the mutations identified were shown to reduce the enzymatic activity. Drosophila nmnat has a neuroprotective role and but it is not clear if LCA is caused by the reduction in NAD production or the loss of a novel neuroprotective mechanism.
Periklis Makrythanasis, MD, PhD