Whole exome sequencing identifies a novel splice-site mutation in IMPG2 gene causing Stargardt-like juvenile macular dystrophy in a north Indian family

A novel lipophenol quercetin derivative to prevent macular degeneration: Intravenous and oral formulations for preclinical pharmacological evaluation

Drugs with properties against oxidative and carbonyl stresses are potential candidates to prevent dry age-related macular degeneration (Dry-AMD) and inherited Stargardt disease (STGD1). Previous studies have demonstrated the capacity of a new lipophenol drug: 3-O-DHA-7-O-isopropyl-quercetin (Q-IP-DHA) to protect ARPE19 and primary rat RPE cells respectively from A2E toxicity and under oxidative and carbonyl stress conditions. In this study, first, a new methodology has been developed to access gram scale of Q-IP-DHA. After classification of the lipophenol as BCS Class IV according to physico-chemical and biopharmaceutical properties, an intravenous formulation with micelles (M) and an oral formulation using lipid nanocapsules (LNC) were developed. M were formed with Kolliphor® HS 15 and saline solution 0.9 % (mean size of 16 nm, drug loading of 95 %). The oral formulation was optimized and successfully allowed the formation of LNC (25 nm, 96 %). The evaluation of the therapeutic potency of Q-IP-DHA was performed after IV administration of micelles loaded with Q-IP-DHA (M-Q-IP-DHA) at 30 mg/kg and after oral administration of LNC loaded with Q-IP-DHA (LNC-Q-IP-DHA) at 100 mg/kg in mice. Results demonstrated photoreceptor protection after induction of retinal degeneration by acute light stress making Q-IP-DHA a promising preventive candidate against dry-AMD and STGD1.

Variants in exon 2 of MED12 gene causes uterine leiomyoma's through over-expression of MMP-9 of ECM pathway

AIMS

To study the impact of Mediator complex subunit 12 (MED12) gene variants on the encoded protein's function and pathogenic relevance for genesis of uterine leiomyoma's (ULs).

METHODS

Mutational analysis in exon-2 of MED12 gene was performed by PCR amplification and DNA sequencing in 89 clinically diagnosed ULs tissues. Pathogenicity prediction of variation was performed by computational analysis. The functional effects of missense variation were done by quantity RT-PCR and western blot analysis.

RESULT(S)

Out of 89 samples, 40 (44.94%) had missense variation in 14 different CDS position of exon-2 of MED12 gene. Out of 40 missense variation, codon 44 had 25 (62.5%) looking as a hotspot region for mutation for ULs, because CDS position c130 and c131present at codon 44 that have necleotide change G>A, T, C at c130 and c131 have necleotide change G>A and C. We also find somenovel somatic mutations oncodon 36 (T > C), 38 (G>T) of exon-2 and 88 (G>C) of intron-2. No mutations were detected in uterine myometrium samples. Our computational analysis suggests that change in Med12c .131 G>A leads to single substitution of amino acid [Glycine (G) to Aspartate (D)] which has a pathogenic and lethal impact and may cause instability of MED12 protein. Further, analysis of extracellular matrix (ECM) component (MMP-2 & 9, COL4A2 and α-SMA) mRNA and protein expression levels in the set of ULs having MED12 mutation showed significantly higher expression of MMP-9 and α-SMA.

CONCLUSION(S)

The findings of present study suggest that missense variation in codon 44 of MED12 gene lead to the genesis of leiomyoma's through over-expression of MMP-9 of ECM pathway which could be therapeutically targeted for non-surgical management of ULs.

IMPG2-associated unilateral adult onset vitelliform macular dystrophy

Purpose

To present a case of unilateral IMPG2-associated adult onset vitelliform macular dystrophy (AVMD).

Observations

A 68 year-old female presented with best corrected visual acuity (BCVA) of 20/20 and 20/40 for the right and left eye respectively. The patient had a left subfoveal yellow lesion on dilated fundus examination. Optical coherence tomography showed hyper-reflective material accumulation below the fovea in the left eye only. The patient was followed for 10 years with stable BCVA, and evolution of the subretinal vitelliform lesion to a “vitelliruptive” stage. The right eye did not develop vitelliform lesion. Genetic testing identified a heterozygous likely disease-causing variant in IMPG2; c.3423–7_3423-4del.

Conclusions and importance

This is the first report of unilateral AVMD associated with IMPG2, expanding the phenotypic spectrum of IMPG2 retinopathy. We provide further evidence that IMPG2 variants can cause both autosomal recessive rod-cone dystrophy and autosomal dominant AVMD, with implications for patient counselling.