Categories: Vision / eye phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 600897 (gene) , 116200 (trait)

Single-gene trait/disorder: yes

Disease-related: yes

Key variant known: yes

Year key variant first reported: 2024

Cross-species summary: The GJA8 gene is also called connexin 50; CX50

Species-specific name: eyeless

Mapping: Kellermeyer et al. (2024) used whole genome sequencing data for a genome-wide association study and identified 7 chromosome regions associated with the eyeless phenotype in Mexican tetra from the Caballo Moro cave.

Molecular basis: Kellermeyer et al. (2024) filtered SNP identified in whole genome sequencing that were homozygous alternate in eyeless Mexican tetra from the Caballo Moro cave and identified a likely causal variant in a positional and functional candidate gene: p.(S89K) in gja8b (also called cx50). The same variant was present "in other Guatemala populations, including Molino, Escondido, and Jineo" but was absent in El Abra lineage Mexican tetra, in which the authors identifed a second likely causal variant in the same gene: p.(T39M). The role of gja8b/cx50 in the phenotype was validated via CRISPR based knockouts of Cx50 in surface fish and mice. This study involves gene edited or genetically modified organisms (GMO).

Genetic engineering: Yes - in addition to the occurrence of natural variants, variants have been created artificially, e.g. by genetic engineering or gene editing
Have human generated variants been created, e.g. through genetic engineering and gene editing

Associated gene: