Detection of female carriers of congenital color-vision deficiencies by visual pigment gene analysis.
OBJECTIVE
Congenital color-vision deficiencies are frequent among males, 4.7-8.0%, suggesting that female carriers are present at a frequency of 9-15%. The purpose of this study was to determine whether carriers could be detected by analysis of the visual pigment genes.


METHODS
DNA from 29 males with congenital color-vision deficiencies, from their mothers, and from 117 randomly-selected females was analyzed. The most upstream genes, the downstream genes, and the most downstream genes in the red/green pigment gene arrays were amplified separately by PCR. Exon 5 of each gene was analyzed by single-strand conformation polymorphisms (SSCP).


RESULTS
Analysis of the visual pigment genes suggests that one of the 29 mothers examined is a female protan and two others are carriers of both protan and deutan defects. The remaining 26 mothers were confirmed to be carriers of congenital color-vision deficiencies. Unusual patterns were observed in 15 (13%) of the randomly-selected females; among them, 5 appeared to be protan carriers and at least 4 to be deutan carriers.


CONCLUSIONS
Female carriers of congenital color-vision deficiencies can be detected by analysis of the visual pigment genes. Since the proportion of females showing unusual patterns was slightly higher than expected, some must be false-positives and require more detailed examination.
Oda
S
S
Department of Ophthalmology, Shiga University of Medical Science, Seta, Otsu, Japan.
Ueyama
H
H
Tanabe
S
S
Tanaka
Y
Y
Yamade
S
S
Kani
K
K
D003118:Color Perception / Q000235:genetics; D003117:Color Vision Defects / Q000151:congenital* / Q000235:genetics; D004247:DNA / Q000032:analysis; D017931:DNA Primers / Q000737:chemistry; D005091:Exons / Q000235:genetics; D005260:Female; D006580:Genetic Carrier Screening / Q000379:methods*; D006579:Heterozygote; D006801:Humans; D008297:Male; D010375:Pedigree; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D017299:Rod Opsins / Q000235:genetics*; D014960:X Chromosome / Q000235:genetics*
D017931:DNA Primers; D017299:Rod Opsins; D004247:DNA