First Author: G.Garcia Garcia SPAIN
Co Author(s): J. Perez-Santonja J. Alvarez-Cebrian M. Martinez-Rubio M. Moya Moya J. Escribano
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Bietti´s crystalline dystrophy (BCD) is a progressive and inherited chorioretinal dystrophy characterized by multiple, yellowish glistening crystalline retinal deposits, geographic areas of atrophy of the retinal pigment epithelium and the choriocapillaris, choroidal sclerosis and crystalline deposits in peripheral cornea. Marginal crystalline keratopathy consist on refringent subepithelial limbal deposit which easily can be missed if not thoroughly searched for or can be hidden by an arcus senilis. To our knowledge, we report the first case of marginal crystalline keratopathy in a Spanish patient and a new pathogenic heterozygous genotype.
The study protocol received approval by the General University Hospital of Alicante´s Joint Committee on Clinical Research, and followed the tenets of the Declaration of Helsinki. Informed consents were obtained from the patient.
The patient underwent a full ophthalmic examination including best corrected visual acuity, slit-lamp examination, in vivo corneal confocal microscopy, dilated fundus examination, OCT assessment of the macula and fluoresceinic angiography. The diagnosis was made on the basis of clinical evaluation (presentation of glistening crystalline retinal deposits, geographic areas of atrophy of the retinal pigment epithelium and the choriocapillaris, sclerosis of the choroid vessels and crystalline deposits in the peripheral cornea), after excluding other causes of crystalline dystrophy. Blood samples were collected and genomic DNA was extracted from the peripheral leukocytes of the participant, and the 11 exons of CYP4V2 were analyzed by direct PCR sequencing. Mutations were confirmed by sequencing the complementary DNA strand and by independent sequencing in a second DNA sample.
We report the case of a 36 years old Spanish male with progressive bilateral vision loss. Fine limbal and peripheral corneal crystals were evident during clinical evaluation by slit lamp examination. Fundus exploration showed a few glistening crystalline deposits on the posterior pole and midperipheral retina, according to an advanced stage of BCD disease. Marked geographic areas of atrophy of the retinal pigment epithelium and the choriocapillaris were registered in fluoresceinic angiography. Retinal optical coherence tomography disclosed a level of high reflectivity throughout the entire neurorretina and changes in the inner retina. Molecular analysis of the CYP4V2 gene revealed a new pathogenic compound heterozygous genotype involving the rare variant p.(Gly95Arg) and the haplotype p.(Ala204Thr) - p.(Arg443Trp).
Bietti´s crystalline dystrophy is a genetic disorder with a variable course in clinic manifestations. We described the first Spanish case of marginal crystalline keratopaty and a new pathogenic complex heterozygous genotype of the causative gene. The patient, despite his age, presented a severe phenotype involving late stages of the BCD disease.