Unusual presentation of cone dysfunction consequent upon a homozygous FAM161A variant.
Jinan Alhamad, Enas Magharbil, Sawsan R Nowilaty et al.
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Case in brief
A 20-year-old male presented with subnormal vision, photophobia, nystagmus, and loss of color vision. Fundus imaging revealed bilateral macular pigmentary mottling and mild retinal vascular attenuation. Optical coherence tomography showed hyporeflective ellipsoid zone layers. Electroretinography indicated isolated cone dysfunction with preserved scotopic responses, stable over 3 years. Genetic testing identified a homozygous frameshifting variant in FAM161A.
What made this case unusual
The case highlights an initial presentation of cone dysfunction in a patient with relatively normal fundoscopic findings, which is atypical for FAM161A retinopathy.
Diagnostic / clinical pearl
Clinicians should consider FAM161A retinopathy in cases of cone dysfunction, even when fundoscopic examination appears normal.
Why it matters
Recognizing this variant of retinopathy can aid in accurate diagnosis and management of patients presenting with unexplained cone dysfunction.