AIM: To describe novel variants in the G protein-coupled receptor kinase 1 (GRK1) gene associated with Oguchi disease and to analyze the different multimodal imaging results. METHODS: Five members of a single family were enrolled, including two confirmed cases of Oguchi disease and three carriers with novel variants in the GRK1 gene. All subjects underwent a comprehensive ophthalmological examination, including color vision testing, visual field testing, wide-field retinography, fundus autofluorescence, macular optical coherence tomography (OCT), and full-field electroretinography (ERG). RESULTS: The study found that both cases of Oguchi disease showed positive Mizuo-Nakamura phenomenon, moderate retinal thickening and packing of the three outermost hyper-reflective bands in the parafoveal region. After establishing a clinical diagnosis of Oguchi disease in patients IV-II and IV-III, molecular analysis revealed a similar genotype in the patients, both carrying two heterozygous variants in the GRK1 gene, the variants c. 1055₁056delAC, p. (Tyr352CysfsTer32) and c. 699+2TC. Genetic testing also revealed that individual III-I was a heterozygous carrier of the novel variant c. 1055₁056delAC in the GRK1 gene. In addition, the novel intronic variant c. 699+2TC was detected in the same gene in the heterozygous state in individuals III-II and IV-I. Family segregation showed that Oguchi disease was transmitted in an autosomal recessive pattern in this family. CONCLUSION: Two novel variants in the GRK1 gene are reported that are linked to Oguchi disease in a naïve Algerian family. The common findings observed on the OCT scans of our affected patients include packing of the three outer hyper-reflective bands, and thickening of the retina in the parafoveal region. These features are present not only in the affected patients but also in the carriers of the disease.
Martín et al. (Wed,) studied this question.