Tapetal-like reflex in RPGR-associated retinal dystrophies: two cases with distinct phenotypes.

INTRODUCTION: Retinitis pigmentosa GTPase regulator (RPGR) mutations are associated with X-linked inherited retinal diseases (IRDs), with variable phenotypes including retinitis pigmentosa (RP), cone-rod dystrophy (CRD), and cone dystrophy (CD). Tapetal-like reflex (TLR) is commonly observed in female carriers and has more recently been reported in hemizygous male patients with cone-dominant or cone-rod phenotypes. Here, we report two male patients with RPGR mutations and TLR. MATERIALS AND METHODS: Clinical history, ophthalmic examination, multimodal retinal imaging, and genetic testing were reviewed in two unrelated Thai males with confirmed RPGR mutations. RESULTS: The first patient was a 9-year-old boy with sector RP and progressive bilateral blurred vision. The second was a 24-year-old man with sector RP and CD. Both exhibited a characteristic TLR at the posterior pole despite being affected males. These cases illustrate the phenotypic variability associated with RPGR mutations and the occurrence of TLR in affected males. CONCLUSION: TLR may serve as a useful clinical clue to RPGR-related disease in both female carriers and affected males, including those with milder phenotypes such as sector RP. In affected males, the presence of TLR may be associated with preserved outer retinal structures and could indicate a milder phenotype, an earlier disease stage, or a more favorable prognosis.