Case Report: Swept-source Optical Coherence Tomography and Angiography Findings in Lipemia Retinalis.

SIGNIFICANCE: Lipemia retinalis is a very rare ocular manifestation of severe hypertriglyceridemia. It is usually symptomatic and regresses after normalization of triglycerides levels. Early recognition is important to prevent ocular and life-threatening complications. PURPOSE: This study aimed to report a case of marked lipemia retinalis secondary to type V hypertriglyceridemia assessed with swept-source optical coherence tomography (OCT) and OCT angiography (OCT-A), with follow-up after dietary lipid restriction. METHODS: Observational case report of lipemia retinal findings on color fundus photography, swept-source OCT and OCT-A, initially and after triglycerides lowering. CASE REPORT: A 32-year-old pregnant patient with gestational diabetes and a history of hypertriglyceridemia was referred for diabetic retinopathy screening. Fundus examination revealed bilateral milky-white discoloration of retinal vessels with a "salmon-colored" retina. Swept-source OCT and OCT-A revealed extremely hyperreflective and dilated retinal vessels and multiple high-flow retinal hyperreflective dots, corresponding to dilated retinal capillaries. Choroidal vessels were enlarged and engorged, and choriocapillaris layer appeared thickened and hyperreflective with dilated and tortuous capillaries. Serum triglycerides were very high (70.02 mmol/L). After 21 days of very-low-fat diet, it was lowered to 15 mmol/L. We noted a normalization of the clinical, structural, and vascular findings. However, peripheral retinal vessels remained hyperreflective, despite their clinical normalization. CONCLUSIONS: Swept-source OCT and OCT-A were beneficial in assessing lipemia retinalis noninvasively and monitoring choroidal and retinal vascular changes. Lipemia retinalis signs regressed initially in the posterior pole, choroidal anomalies were first to resolve, and clinical normalization preceded tomographic resolution.

[Molecular exploration of the R91W (RPE65 gene) in Tunisian patients with early onset retinal dystrophy and early onset retinitis pigmentosa]. / Exploration moléculaire de la R91W (gene RPE65) chez des patients Tunisiens atteints de "Early Onset Retinal Dystrophy" et de la rétinopathie pigmentaire à age de début précoce.

BACKGROUND: Inherited retinal dystrophies are the major causes of blindness and visual impairment. Visual loss is due to neurosensory retinal and pigment epithelium cells degeneration. The most severe were Leber Congenital amaurosis (LCA), juvenile retinitis pigmentosa (RP) and early onset RP. The LCA and juvenile RP are called «Early Onset Retinal Dystrophy¼ (EORD). OBJECTIVE: Molecular exploration of the R91W (RPE65 gene) in Tunisian patients with Early Onset Retinal Dystrophy and early onset RP. METHODS: All patients underwent a complete ophthalmological and a general examinations. The R91W exploration was performed by direct sequencing of exon 4 of the RPE65 gene and enzyme digestion. RESULTS: Among 47 patients, 13 were from Nabeul. Twenty three had an EROD with a visual loss under the age of 2 years. Twenty four were with early onset RP and had these symptoms between the ages of 4 and 10 years. The best corrected visual acuity ranged from 2/10 to 1/60. Among the explored 94 chromosomes, the R91W (325C>T) allele was identified in heterozygous state in a sibling from Nabeul. The allele frequency was 2.12% (2/94). CONCLUSION: All our patients had severe forms of RP with a decrease in visual acuity and a wide advanced retinal degeneration. The R91W mutation (325C>T) was not the major cause of EORD and early onset RP among Tunisian patients.

Molecular analysis of the PAX6 gene for aniridia and congenital cataracts in Tunisian families.

The aim of this study was to identify the genetic defect that is responsible for aniridia and congenital cataracts in two Tunisian families. Sequencing of the PAX6 gene in family F1 detected a novel c.265C>T transition in exon 6. In family F2, the previously described c.718C>T mutation in PAX6 was detected in the four affected members. This study adds new mutation to those previously reported in PAX6, providing further evidence for the genetic and phenotypic heterogeneity in individuals with aniridia ocular malformations.

Clinical and genetic investigation of a large Tunisian family with complete achromatopsia: identification of a new nonsense mutation in GNAT2 gene.

Complete achromatopsia is a rare autosomal recessive disease associated with CNGA3, CNGB3, GNAT2 and PDE6C mutations. This retinal disorder is characterized by complete loss of color discrimination due to the absence or alteration of the cones function. The purpose of the present study was the clinical and the genetic characterization of achromatopsia in a large consanguineous Tunisian family. Ophthalmic evaluation included a full clinical examination, color vision testing and electroretinography. Linkage analysis using microsatellite markers flanking CNGA3, CNGB3, GNAT2 and PDE6C genes was performed. Mutations were screened by direct sequencing. A total of 12 individuals were diagnosed with congenital complete achromatopsia. They are members of six nuclear consanguineous families belonging to the same large consanguineous family. Linkage analysis revealed linkage to GNAT2. Mutational screening of GNAT2 revealed three intronic variations c.119-69G>C, c.161+66A>T and c.875-31G>C that co-segregated with a novel mutation p.R313X. An identical GNAT2 haplotype segregating with this mutation was identified, indicating a founder mutation. All patients were homozygous for the p.R313X mutation. This is the first report of the clinical and genetic investigation of complete achromatopsia in North Africa and the largest family with recessive achromatopsia involving GNAT2; thus, providing a unique opportunity for genotype-phenotype correlation for this extremely rare condition.