Manifestations of rod monochromacy

Rod monochromacy or total color blindness is a rare autosomal recessively inherited disorder. In a high percentage of individuals, it is caused by mutations in the CNGA3 gene, which encodes the cr-subunit of the cone photoreceptor cGMP-gated cation channel. We assessed visual function in affected individuals with homozygous and compound heterozygous mutations and in heterozygous carriers in families carrying different mutations in the CNGA3 gene. Our psychophysical and electroretingoraphic tests demonstrate that the severity of rod monochromacy depends upon the nature and combination of the mutations in the CNGA3 gene. (C) 2000 John Wiley & Sons, Inc. Col Res Appl, 26, S96-S99, 2001.