Manifestations of rod monochromacy

Rod monochromacy or total color blindness is a rare autosomal recessively i nherited disorder. In a high percentage of individuals, it is caused by mut ations in the CNGA3 gene, which encodes the cr-subunit of the cone photorec eptor cGMP-gated cation channel. We assessed visual function in affected in dividuals with homozygous and compound heterozygous mutations and in hetero zygous carriers in families carrying different mutations in the CNGA3 gene. Our psychophysical and electroretingoraphic tests demonstrate that the sev erity of rod monochromacy depends upon the nature and combination of the mu tations in the CNGA3 gene. (C) 2000 John Wiley & Sons, Inc. Col Res Appl, 2 6, S96-S99, 2001.