Correlation of gene structure and psychophysical measurement in red-green color vision deficiency in Chinese

Purpose: To study the correlation of genotype for X-linked red-green gene a rray with color vision phenotype in 58 subjects with red-green color vision deficiency. Methods: The molecular structure of red and green pigment genes on 58 X chr omosomes was studied exon-by-exon by using heteroduplex-SSCP analysis and s equencing. The color vision of these subjects was determined by a Neitz ano maloscope. Results: Variations in the red and green pigment genes were detected in 43 subjects and a hybrid gene was found in 27 subjects. About 50% of the fusio n sites occurred at intron 2-3. All 3 anomalous trichromats with intron 4 f usion were mild type but another 3 with intron 2-3 fusion were severe type. No subjects with mild type of color vision defects had a fusion site at in tron 2-3 or its upstream. Three subjects with complete deletion of the gree n pigment gene manifested deuteranomaly. Conclusions: Protans can be differentiated from deutans on the basis of gen otype. It is still difficult to establish a clear correlation of different anomalous trichromats with genotype. The fusion site of a hybrid gene affec ts the phenotype to some degree. Intron 2-3 is the common place for gene cr ossover. (C) 2000 Japanese Ophthalmological Society.