Usher syndrome (USH) is an autosomal recessive disorder characterized by combined deafness-blindness. It accounts for about 50% of all hereditary deafness blindness cases. Three clinical subtypes (USH1, USH2, and USH3) are described, of which USH1 is the most severe form, characterized by congenital profound deafness, constant vestibular dysfunction, and a prepubertal onset of retinitis pigmentosa. We performed whole exome sequencing in four unrelated Tunisian patients affected by apparently isolated, congenital profound deafness, with reportedly normal ocular fundus examination. Four biallelic mutations were identified in two USH1 genes: a splice acceptor site mutation, c.2283-1G>T, and a novel missense mutation, c.5434G>A (p.Glu1812Lys), in MYO7A, and two previously unreported mutations in USH1G, i.e. a frameshift mutation, c.1195_1196delAG (p.Leu399Alafs*24), and a nonsense mutation, c.52A>T (p.Lys18*). Another ophthalmological examination including optical coherence tomography actually showed the presence of retinitis pigmentosa in all the patients. Our findings provide evidence that USH is under-diagnosed in Tunisian deaf patients. Yet, early diagnosis of USH is of utmost importance because these patients should undergo cochlear implant surgery in early childhood, in anticipation of the visual loss.
In highly myopic eyes, the choroid is thin and undergoes further attenuation with age and increasing myopia. In addition, these findings suggest that the choroid may play a role in the pathogenesis of CNV.
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.119À69G4C, c.161+66A4T and c.875À31G4C 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.
Introduction:To present a case of chemotherapeutic regression of metastasis of breast carcinoma to the choroid in a male patient. Case Report: A 63yearold male, with a past medical history of breast cancer, presented with blurred vision and progressive loss of visual acuity. Fundoscopy of the right eye revealed a choroidal mass in the upper temporal arcade associated with pigment epithelium impairment. Optic disc was normal and macular edema was not present. The patient was treated with systemic chemotherapy (epirubicin, cyclophosphamide, 5fluorouracil), every three weeks, for six cycles. Five months into treatment, the patient reported a partial improvement in visual symptoms. A complete regression of the choroidal mass was noted with both magnetic resonance imaging and fundoscopy. Conclusion: In male as in female patients, breast carcinoma may metastasize to the choroid. Such metastasis must be suspected whenever a patient with a past history of breast cancer suffers from impaired vision. An appropriate ophthalmologic examination including fundoscopy should be performed. Treatment strategy is still based essentially on radiotherapy and should be modified individually depending on size, localization and presence of metastases to other organs and general condition of the patient.
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