Researchers in Taiwan developed a new genotyping strategy that can reliably identify color blindness among patients with hemophilia A, as published in Talanta. Their method could be useful in many fields including disease diagnosis, polymorphisms analysis, and quantitative assays.

The development of the new method stems from the fact that traditional genetic analysis methods are time-consuming and not always very efficient. The present method developed by Tzu-Yu Pan and colleagues allows for the simultaneous evaluation of 10 exons in the red and green pigment genes.

The red and green pigment genes are arranged in tandem on the q-arm of the X-chromosome at location Xq28 and constitute the visual pigment gene array.

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In patients with normal color vision, 1 or 2 green pigment genes follow a red pigment gene. Each of these genes has 6 exons and shares the same exon 1 and exon 6 between them.

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Deletions or structural rearrangements in the visual pigment gene array alter the function of the visual pigments and cause color blindness. Because the mutated factor VIII gene is also located at Xq28, the incidence of color blindness is closely associated with hemophilia A and other X-linked recessive disorders.

The researchers analyzed all polymerase chain reaction products obtained with this new method and found that of all 80 detected individuals, 7 had color vision deficiencies. Among these, 3 had only red exons 1 to 5, and 4 had a specific red-green or green-red hybrid gene. All genotyping results were in agreement with DNA sequencing data.

“This method provided a better potential technique for genotyping and identifying of red and green pigment genes,” the researchers concluded. They added that it is speedy, accurate, low cost, and less labor-intensive in genetic diagnosis.


Pan TY, Kou HS, Wu SM, Wang CC. Identifiable universal fluorescent multiplex PCR equipped with capillary electrophoresis for genotyping of exons 1 to 5 in human red and green pigment genes. Talanta. Published online January 1, 2022. doi:10.1016/j.talanta.2021.123199