Familial Drusen, Doyne Honeycomb Retinal Dystrophy (Malattia Leventinese), Pigmented Paravenous Chorioretinal Atrophy and Late-Onset Retinal Degeneration

Inherited retinal diseases are a group of rare, heterogeneous eye disorders caused by gene mutations that result in degeneration of the retina. Malattia Leventinese, also known as familial drusen, dominant drusen, or Doyne honeycomb retinal dystrophy, was first described in patients living in the Levantine Valley in canton Ticino of southern Switzerland in 1925. Characteristic clinical findings include radial macular drusen, large confluent drusen, and juxtapapillary drusen. Especially early visual symptoms typically starting in the 3rd and 5th decades include reduced central vision, photophobia, and metamorphopsia. Pigmented paravenous retinochoroidal atrophy (PPRCA) is an uncommon disease characterized by perivenous aggregations of pigment clumps associated with peripapillary and radial zones of retinochoroidal atrophy that are distributed along the retinal veins. Patients are usually asymptomatic and the disease process is non-progressive or slow and subtly progressive. It is commonly bilateral and symmetric. The autosomal- dominant late-onset retinal degeneration (L-ORD), caused by C1QTNF5 gene mutations, shows typical retinal abnormalities that can extend beyond the macula, and patients can report night blindness in addition to central vision loss. Interestingly, L-ORD patients can have long anteriorly inserted lens zonules and loss of iris pigment.

Utility of pattern recognition and multimodal imaging in the diagnosis and management of doyne honeycomb retinal dystrophy complicated with type one choroidal neovascular membrane

A 44-year-old woman presented with decreased vision in both eyes. The retina in both eyes had drusen distributed along vascular arcades, central macula and in peripapillary region. Macula had pigmented scarring and exudation. Fundus autofluorescence showed drusen. Optical coherence tomography showed drusen, subretinal and intraretinal fluid. Fundus fluorescein and indocyanine green angiography showed drusen, retinal pigment epithelial atrophy and vascular network. Younger age at presentation, bilateral symmetry, typical distribution of drusen along the arcades in a radiating pattern, peripapillary involvement, scarring and atrophy at macula were suggestive of doyne honeycomb retinal dystrophy. The reduced vision was due to macular atrophy and an active choroidal neovascular membrane. The patient was treated with antivascular endothelial growth factor injections for choroidal neovascular membrane. Our case highlights the importance of pattern recognition and multimodal imaging for diagnosing the type of macular dystrophy as doyne honeycomb retinal dystrophy, while simultaneously managing choroidal neovascular membrane.

Genetic testing for Doyne honeycomb retinal dystrophy

We studied the scientific literature and disease guidelines in order to summarize the clinical utility of genetic testing for Doyne honeycomb retinal dystrophy (DHRD). The disease has an autosomal dominant inheritance and is caused by variations in the EFEMP1 gene. There is insufficient data to establish the prevalence of DHRD. Clinical diagnosis is based on clinical findings, ophthalmological examination, electroretinography, fluorescein angiography and optical coherence tomography. The genetic test is useful for confirming diagnosis, and for differential diagnosis, couple risk assessment and access to clinical trials.