Background: To present the retinal and systemic findings in two siblings with compound heterozygous MPDZ variants that were found to have different chorioretinal manifestations. Materials and Methods: Two sibling patients underwent comprehensive ophthalmic examination, including ophthalmoscopy, fundus photography, optical coherence tomography (OCT), and genetic testing by whole exome sequencing.
Results: A 4-year-old male presented with intermittent exotropia and decreased vision in both eyes. Ophthalmologic examination was notable for macular colobomas and far temporal chorioretinal atrophy in both eyes. OCT of the macula in both eyes demonstrated a caldera with severe retinal and choroidal thinning. Fluorescein angiography of the central macula showed hypofluorescence with persistence of deep choroidal vessels. An ocular gene panel was nondiagnostic, but subsequent whole-exome sequencing noted compound heterozygous, likely pathogenic MPDZ variants (c.3100C>T p.(Arg1034*) from father and c.747 + 2T>G p.(?) from mother). His older brother, a 9-year-old male, had a history of macrocephaly but had not undergone further workup. On exam, he had a visual acuity of 20/25 in the right eye and 20/40 in the left eye and was found to have subtle changes in the foveal reflex of both eyes. OCT revealed thinning of the outer nuclear layer (ONL) temporal to the fovea bilaterally. Sanger sequencing revealed he was positive for the same two MPDZ variants.
Conclusions: MPDZ variants have been described in cases of congenital hydrocephalus with varying ophthalmologic manifestations. We present a case series describing retinal phenotypes associated with MPDZ variants in a single family through multimodal imaging.
Keywords: Chorioretinal coloboma; MPDZ; MUPP1; claudin; hydrocephalus; inherited retinal dystrophy; multi-PDZ domain protein-1; tight junctions.