Khateb S, et al. - Via a cohort, longitudinal, follow-up study of 54 subjects from a cohort of 1,095 index patients with rod-cone dystrophy (RCD) and mutations in PDE6A or PDE6B from January 2007 to September 2017, the researchers intended to contrast the genotype, phenotype, and structural changes, for disease modeling as a basis for prospective therapeutic interventions. Nineteen out of 54 subjects of 17 families carried pathogenic mutations in PDE6A estimating for prevalences of 1.6%, and 35 subjects of 26 families had mutations in PDE6B, accounting for prevalences of 2.4%, respectively. Forteen and 15 in PDE6A and in PDE6B, respectively, among 49 identified genetic variants were novel. No substantial variations among the 2 groups except for night blindness as a presenting complaint that was observed to be more prevalent in the PDE6A than PDE6B group was discovered. Comparable values of mean binocular best-corrected visual acuity and kinetic visual fields decrease over time (measured as mean individual slopes coefficients) was ascertained among subjects with PDE6A and PDE6B mutations. Hence, in a cohort of French patients with RCD, it was concluded that mutations in PDE6A and PDE6B accounted for 1.6% and 2.4%, respectively. Moreover, for better prognostic estimation and candidate selection for photoreceptor therapeutic rescue, the functional and structural otcomes noted could constitute the basis of disease modeling that might be utilized.