Multimodal imaging of ring 14 syndrome associated maculopathy

North Carolina macular dystrophy shows a particular drusen phenotype and atrophy progression

BACKGROUND/AIM

To provide a comprehensive multimodal retinal imaging characterisation of patients with North Carolina macular dystrophy (NCMD).

METHODS

Clinical evaluation and retinal imaging in six families.

RESULTS

Twenty-one subjects showed phenotypic characteristics of NCMD . Small drusen-like deposits were found in all affected individuals, either tightly grouped in the macula, or surrounding atrophic or fibrotic macular alterations. These small subretinal lesions showed an increased fundus autofluorescence and were associated with only mild irregularities on optical coherence tomography imaging. Similar drusen-like deposits were regularly seen in the peripheral fundus, predominantly temporally and often with a radial distribution. Two patients showed a bilateral chorioretinal atrophy and two had a macular neovascularisation (MNV). Findings from follow-up examinations were available from 11 patients. The retinal phenotype remained overall stable, except for two patients: one patient with atrophy showed a distinct growth of the atrophic lesions on longitudinal AF imaging over a review period of 14 years. One patient with MNV showed a unilateral decline of best-corrected visual acuity. Genetic testing identified the single nucleotide variant chr6:100040987G>C upstream of the PRDM13 gene in all family members with NCMD phenotype.

CONCLUSION

Patients with NCMD show a characteristic retinal phenotype and distribution of drusen that differ from drusen in patients with age-related macular degeneration. Although the prognosis of this developmental condition is overall better than for other macular diseases with drusen, patients may be at risk of developing MNV or enlargement of pre-existing atrophy.

Practical guide to genetic screening for inherited eye diseases

Genetic eye diseases affect around one in 1000 people worldwide for which the molecular aetiology remains unknown in the majority. The identification of disease-causing gene variant(s) allows a better understanding of the disorder and its inheritance. There is now an approved retinal gene therapy for autosomal recessive RPE65-retinopathy, and numerous ocular gene/mutation-targeted clinical trials underway, highlighting the importance of establishing a genetic diagnosis so patients can fully access the latest research developments and treatment options. In this review, we will provide a practical guide to managing patients with these conditions including an overview of inheritance patterns, required pre- and post-test genetic counselling, different types of cytogenetic and genetic testing available, with a focus on next generation sequencing using targeted gene panels, whole exome and genome sequencing. We will expand on the pros and cons of each modality, variant interpretation and options for family planning for the patient and their family. With the advent of genomic medicine, genetic screening will soon become mainstream within all ophthalmology subspecialties for prevention of disease and provision of precision therapeutics.