Purpose. In previous studies we have shown that 4- and 8-week-old infants demonstrate visually-evoked potential (VEP) responses to M- and L-cone isolating stimuli. While most infants displayed relatively similar VEP responses to both Mand L-cone isolation, four male infants demonstrated strong responses to only one cone-isolating stimulus (either M or L), displaying little or no response to the other. Based on these data, as well as verbal reports of a maternal history of color vision deficiency, these infants were classified as suspect color defective. As a follow-up, genetic analyses were performed on 3 of these infants, 2 suspect color-normal infants and 4 adults to evaluate the ratio of L:M cone photopigment genes from each individual. Methods. A non-invasive genomic DNA-isolation technique was used to collect samples of cheek cells from 4 adults (with various diagnoses of color vision) and 5 infants. PCR amplification and restriction analysis were used to examine the genomic DNA from each subject. Results. There was significant but imperfect agreement between the pheno- and genotypic classification (κ=0.67; p=0.003). Genotypic classification for each adult was consistent with the phenotype. Two of the suspect color defective infants had a single X-chromosome pigment gene and were, thus, obligate dichromats. For the two suspect color-normal infants, one displayed a genotype consistent with a normal phenotype and the other with a protan phenotype. One infant suspect for a protan defect appeared to have pigment genes that would be unexpected for a protan defect. Conclusions. We find a significani correspondence between genetic and phenotypic markers. These data provide additional evidence for the functioning of M- and L-cones as early as 4-weeks. The receptor-isolation technique seems capable of identifying color deficient infants as young as 4-weeks.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - 1997|
ASJC Scopus subject areas