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BackgroundBiallelic pathogenic variants in the ATP-binding cassette subfamily C member 6 (ABCC6) gene cause pseudoxanthoma elasticum, a multisystemic ectopic calcification disorder, while heterozygous ABCC6 variants are associated with an increased risk of cardiovascular and cerebrovascular disease. As the prevalence of pathogenic ABCC6 variants in the general population is estimated at ~1%, identifying additional ABCC6-related (sub)clinical manifestations in heterozygous carriers is of the utmost importance to reduce this burden of disease. Here, we present a large Belgian cohort of heterozygous ABCC6 carriers with comprehensive clinical, biochemical and imaging data. Based on these results, we formulate clinical practice guidelines regarding screening, preventive measures and follow-up of ABCC6 carriers.MethodsThe phenotype of 56 individuals carrying heterozygous pathogenic ABCC6 variants was assessed using clinical (eg, detailed ophthalmological examinations), biochemical, imaging (eg, cardiovascular and abdominal ultrasound) and genetic data. Clinical practice guidelines were then drawn up.ResultsWe found that ABCC6 heterozygosity is associated with distinct retinal alterations (‘comet-like’) (24%), high prevalence of hypercholesterolaemia (>75%) and diastolic dysfunction (33%), accelerated lower limb atherosclerosis and medial vascular disease, abdominal organ calcification (26%) and testicular microlithiasis (28%), though with highly variable expression.ConclusionIn this study, we delineated the multisystemic ABCC6 heterozygosity phenotype characterised by retinal alterations, aberrant lipid metabolism, diastolic dysfunction and increased vascular, abdominal and testicular calcifications. Our clinical practice guidelines aimed to improve early diagnosis, treatment and follow-up of ABCC6-related health problems.

ObjectiveREFLECT is the first randomised, double-masked, placebo-controlled multicentre phase 3 clinical trial that evaluated the efficacy and safety of bilateral intravitreal (IVT) injection of lenadogene nolparvovec in subjects with Leber hereditary optic neuropathy carrying the m.11778G>A mutation.Methods and analysisA total of 98 subjects were enrolled with vision loss of ≤12 months. The subjects were randomised to one of two treatment arms with all subjects receiving an intravitreal (IVT) injection of lenadogene nolparvovec in their first affected eye and the second-affected eye randomised to receive IVT of either lenadogene nolparvovec or placebo.ResultsThe majority of subjects were male with a mean duration of vision loss of 8.3 months. All but one subject experienced bilateral loss of vision at the time of injection. The mean best-corrected visual acuity of first-affected eyes was worse compared with second/not-yet-affected eyes. Analysis of retinal anatomical parameters showed increased thinning in the first-affected eyes when compared with the second/not-yet-affected eyes with both treatment arms showing significant changes compared with unaffected individuals.ConclusionThe REFLECT trial is the third and the largest phase 3 clinical study evaluating lenadogene nolparvovec in m.11778G>A Leber hereditary optic neuropathy (LHON) subjects. The observed demographics in REFLECT are consistent with previous reports in LHON subjects in the acute and dynamic phases of LHON disease. Combined with the visual function and anatomical parameters obtained in the previous RESCUE and REVERSE trials, REFLECT has provided a uniformly collected data set that should help direct future LHON clinical trials.

Purpose: Pseudoxanthoma Elasticum (PXE) is an autosomal recessive disorder caused by mutations in the ABCC6 gene, and primarily affects the oculocutaneous and cardiovascular systems. However, the phenotype, including the ophthalmological manifestations, varies in severity. The present study aims to evaluate the added value of novel fundoscopic imaging techniques, such as infrared, red-free and autofluorescence imaging in PXE. Methods: In 22 molecularly proven PXE patients and 25 obligate carriers, PXE retinopathy was evaluated using funduscopy, white light, red-free, infrared and autofluorescence imaging. Results: At least one characteristic of PXE retinopathy was evident on fundoscopy of all eyes. Angioid streaks could be subdivided in those with (brick red) or without (feathered) adjacent RPE alterations. Infrared imaging showed the brick red coloured streaks as well-demarcated dark fissures, even when these passed unnoticed on funduscopy. Feathered types were detected as triangular areas of hypo-autofluorescence. The peau d’orange was much better visible and much more widespread on infrared imaging, with extension from the posterior pole towards the whole midperiphery. Comets and comet tails were best seen with red-free imaging. Conclusions: Infrared, red-free and autofluorescence imaging are more sensitive than white light funduscopy and imaging in visualizing early retinal signs of PXE. In addition, this specialised imaging allows better appreciation of the extent of lesions. Hence, such imaging increases the chances of making a correct diagnosis early, and aids in the accurate evaluation of evolution of disease in the ophthalmic follow-up of PXE patients.

Objectives: To identify suspected RDS mutations in families in which different people have been identified with either generalised retinal dystrophy or macular dystrophy. Methods: Two families with a retinal dystrophy were extensively phenotyped and blood was taken for mutation analysis of the RDS (all) and ROM1 (retinitis pigmentosa patients only) genes. Results: A novel p.Trp94X mutation in RDS was found in all three affected members of a two-generation family that was associated with retinitis pigmentosa in the son, pattern dystrophy in the daughter and fundus flavimaculatus in the mother. In the second family, the proband with retinitis pigmentosa carried a p.Arg220Trp mutation. The mother, who was unavailable for mutation screening, had adult vitelliform macular dystrophy. No ROM1 mutations were found in those with retinitis pigmentosa in either family. Conclusion: Mutations in RDS can be associated with an intrafamilial variation in retinal disease. The phenotypes range from Stargardt-like macular dystrophy to classic retinitis pigmentosa. Clinical relevance: Intrafamilial phenotypic variation may be due to the presence of environmental or genetic modifying factors. The presence of a modifying-sequence change in the coding region of ROM1 for two people with retinitis pigmentosa from two families with intrafamilial variation in RDS mutation phenotype has been excluded in this study.