CTNNA1-associated retinal dystrophy: novel multimodal imaging and electrophysiology features

To describe multimodal imaging and electrophysiology features of CTNNA1-associated retinal dystrophy in a family with p.(Leu318Ser) substitution.

Three family members including a 48-year-old male proband, his 52-year-old sister, and their 67-year-old mother, were evaluated with multimodal imaging and electrophysiology. The proband, referred with suspected Best's disease, underwent a retinal dystrophy panel and two affected family members were target sequenced for the familial variant.

The NM_001903.5:c.953T > C variant in CTNNA1 segregated with affected family members. They maintained a visual acuity of 20/25 or better throughout 2-4 years of follow-up. The proband exhibited butterfly-shaped pigment dystrophy whilst his sister had no macular lesions, and their mother had foveal pigmentary changes. All three displayed peripheral retinal reticular pigmentation with variable atrophy. Microperimetry demonstrated enlarging paracentral scotoma in the proband whilst Esterman binocular suprathreshold test showed reproducible peripheral loss in the proband's sister. Multifocal electroretinography (ERG) confirmed central macular dysfunction in the proband. In all three, full-field ERG showed mildly delayed dark-adapted (DA) 0.01 b-wave and DA3.0 a-wave, and a light-rise of < 1.7 in one or both eyes on electro-oculography (EOG).

CTNNA1-associated retinal dystrophy due to p.(Leu318Ser) has a unique peripheral retinal phenotype despite variable macular involvement. Reduced EOG light-rise and peripheral reticular pigmentation should raise suspicion of CTNNA1 in butterfly-shaped pigment dystrophy.