Fry LE, Patrício MI, Williams J, et al. - Researchers investigated whether genotype could explain a mild choroideremia phenotype. In this case series study, a mild phenotype was identified in 2 patients with a splice site variant outside the canonical donor sequence (c.940+3delA) vs a cohort of 30 patients with choroideremia. Residual levels of full-length CHM transcript was observed in mildly affected patients, while no CHM transcript was expressed in a control patient with normal disease progression due to a canonical donor splice site variant (c.940+2T>A). The findings thereby suggest an association of residual levels of full-length CHM transcript with milder disease, affording evidence of a relation of genotype with phenotype in choroideremia and implying the transcript level needed to slow degeneration with gene therapy.