Disease relevance of Color Vision Defects

• Mutations in CNG channel genes give rise to retinal degeneration and color blindness [1].
• Initially, a diagnosis of cone-rod dystrophy, achromatopsia, Leber's congenital amaurosis, or Bardet-Biedl syndrome may be made [2].
• CONCLUSION: As described in patients with other retinal diseases such as achromatopsia and congenital stationary night blindness, nystagmus of patients with Bardet-Biedl syndrome can mimic spasmus nutans [3].
• However, the variables such as cigarette smoking, alcohol drinking, peanut consumption, frequent intake of raw fish, heart diseases, peptic ulcer, malaria, hypertension, diabetes, color blindness, G-6-PD deficiency, surgical operation, blood transfusion, and liver diseases of parents and children were not found to be associated with PHC [4].

Psychiatry related information on Color Vision Defects

• Linkage analyses of bipolar disorder with the chromosome 11p15 DNA markers HRAS1 and INS, and the chromosome Xq28 markers for color blindness and G6PD have been reported [5].

High impact information on Color Vision Defects

• A second locus at 8q21-q22 has been identified among the Pingelapese islanders of Micronesia, who have a high incidence of recessive achromatopsia (MIM 262300) [6].
• Numerous reports have been published concerning linkage of X-chromosome markers of the q28 region (including protan and deutan color blindness [CB] and glucose-6-phosphate dehydrogenase deficiency) to manic-depressive illness [7].
• Linkage between an X-chromosome marker (deutan color blindness) and bipolar affective illness. Occurrence in the family of a lithium carbonate-responsive schizo-affective proband [8].
• Our results demonstrate that GNAT2 is the third gene implicated in achromatopsia [9].
• CNGA3 mutations were detected not only in patients with the complete form of achromatopsia but also in incomplete achromats with residual cone photoreceptor function and (rarely) in patients with evidence for severe progressive cone dystrophy [10].

Chemical compound and disease context of Color Vision Defects

• MATERIALS AND METHODS: Urologists were tested with the Farnsworth Dichotomous Test for Color Blindness (D-15) and the Farnsworth-Munsell 100-Hue Test (FM-100) without (control) and with laser eye protection devices for coumarin green, alexandrite and holmium:YAG lasers [11].
• Ethambutol-induced color-blindness in goldfish: a behavioral, electrophysiological and morphological study [12].
• CLINICAL RECORD: A 28-year-old male patient presented five months after carbon monoxide poisoning with achromatopsia [13].
• Pheniprazine, known to induce red-green color blindness, was found to disrupt a wavelength discrimination in pigeons [14].

Biological context of Color Vision Defects

• We here report the identification of five independent families with achromatopsia that segregate protein-truncation mutations in the GNAT2 gene, located on chromosome 1p13 [9].
• Both adrenoleukodystrophy (ALD) and red/green color blindness have been mapped to the distal long arm of the human X chromosome (Xq28) [15].
• Congenital X-linked incomplete achromatopsia. Evidence for slow progression, carrier fundus findings, and possible genetic linkage with glucose-6-phosphate dehydrogenase locus [16].
• Mapping of a novel locus for achromatopsia (ACHM4) to 1p and identification of a germline mutation in the alpha subunit of cone transducin (GNAT2) [17].
• Linkage disequilibrium between glucose-6-phosphate dehydrogenase deficiency and congenital color blindness in Turkish population [18].

Anatomical context of Color Vision Defects

• The phenotypic characteristics of cpfl1 mice are similar to those observed in patients with complete achromatopsia (ACHM2, OMIM 216900) and the cpfl1 mutation is the first naturally-arising mutation in mice to cause cone-specific photoreceptor function loss. cpfl1 mice may provide a model for congenital achromatopsia in humans [19].

Gene context of Color Vision Defects

• Recently, mutations in the gene encoding the CNGB3 subunit have been linked to achromatopsia in humans [20].
• Most remarkably, all Med 1 G6PD-deficient individuals also had red/green color blindness [21].
• Rod monochromacy (complete congenital achromatopsia) is inherited as an autosomal recessive trait of unknown genetic location [22].
• Canine CNGB3 mutations establish cone degeneration as orthologous to the human achromatopsia locus ACHM3 [23].
• A frameshift insertion in the cone cyclic nucleotide gated cation channel causes complete achromatopsia in a consanguineous family from a rural isolate [24].

Analytical, diagnostic and therapeutic context of Color Vision Defects

• Differential diagnosis of typical and atypical congenital achromatopsia. Analysis of a progressive foveal dystrophy and a nonprogressive oligo-cone trichromasy (general cone dysfunction without achromatopsia), both of which at first had been diagnosed as achromatopsia [25].

References