ABSTRACT
Objetivo: La retinosis pigmentaria es la degeneración retiniana hereditaria más frecuente. Las manifestaciones clínicas son variables en lo que se refiere a severidad, edad de inicio y progresión. Esta heterogeneidad clínica es paralela a la heterogeneidad genética (hasta el momento actual se han descrito más de 20 loci diferentes). Los objetivos de este trabajo fueron identificar mutaciones puntuales en el gen de la rodopsina y determinar las frecuencias de los diferentes tipos genéticos de retinosis pigmentaria en la población gallega. Métodos: Hemos estudiado a 47 pacientes, previamente diagnosticados de retinosis pigmentaria, y a sus familiares. Las diferentes formas genéticas se establecieron según los datos recogidos de la historia familiar y los derivados de la exploración clínica. Se realizó un estudio de screening, para la búsqueda de mutaciones puntuales en el gen de la rodopsina, mediante amplificación por reacción en cadena de la polimerasa, análisis por SSCPs y secuenciación directa en 36 pacientes no emparentados con RP no sindrómica. Resultados: Presentamos la distribución por frecuencias de las diferentes formas genéticas de la RP. En el análisis mediante SSCPs del gen de la rodopsina, encontramos diferentes patrones de movilidad: 1 variante en la región 5' no codificante del gen y 1 variante en el tercer intrón. La secuenciación directa demostró dos transiciones: A269®G y C3982®T, respectivamente. Ademas, observamos un cambio de base en el codón 160 (C®A) de este gen. Conclusiones: Los polimorfismos son hallazgos comunes en los exones 1 y 3 del gen de la rodopsina. Son variaciones neutras y no conllevan cambio en la proteína. No hemos encontrado diferencias significativas en la frecuencia de los polimorfismos A269®G y C3982®T entre los tres grupos de pacientes y los individuos normales. No hubo desviación significativa del equilibrio Hardy-Weinberg en ninguno de los grupos (AU)
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Subject(s)
Middle Aged , Child , Adolescent , Adult , Aged , Male , Female , Humans , Point Mutation , Spain , Rhodopsin , Retinitis PigmentosaABSTRACT
PURPOSE: Retinitis pigmentosa (RP) is the most prevalent inherited degeneration in the retina. The clinical manifestations are variable in terms of severity, age of onset and progression. The clinical variation is paralleled by genetic heterogeneity (more than 20 different loci have been described to date). The aim of this work was to identify mutations in rhodopsin gene and to determine the frequencies of the different genetic forms of RP in the Galician population. METHODS: 47 previously diagnosed RP patients and their relatives were studied. Genetic forms of RP were identified by recording full family history and clinical examination. DNA samples from patients with RP and control individuals were screened for point mutations in the rhodopsin gene by using PCR SSCPs (Single Strand Conformation Polymorphisms) and direct sequencing in 36 unrelated nonsyndromic RP patients. RESULTS: We report the frequency distribution of the different genetic RP forms. In the SSCPs analysis of rhodopsin gene we found different mobility shifts: one variant in the 5'-untranslated region of the gen and one variant in the third intron. Direct sequencing revealed an A269-->G and an C3982-->T transitions, respectively. Additionally, we observed a single base change in codon 160 (C-->A) of this gene. CONCLUSIONS: Polymorphisms are commom findings in the exon 1 and 3 of rhodopsin gene. They are neutral variations and do not represent a change in the protein. No significant differences in the frecuencies of A269-->G and C3982-->T polymorphisms among the three groups of RP patients (ADRP, ARRP, Esporadic RP) and normal individuals were found. There was no significant deviation from Hardy-Weinberg's equilibrium in each genotype in any group.
Subject(s)
Point Mutation , Retinitis Pigmentosa/genetics , Rhodopsin/genetics , Adolescent , Adult , Aged , Child , Female , Humans , Male , Middle Aged , SpainABSTRACT
BACKGROUND: Abnormal vitreoretinal relationships have recently been implicated in many vitreoretinal disorders. Sites of abnormal vitreoretinal adherences are likely to exist in eyes predisposed to rhegmatogenous retinal detachment (RD), causing either retinal tears or incomplete posterior vitreous detachment (PVD). The present study was designed in two parts to identify the risk for preoperative and postoperative proliferative vitreoretinopathy (PVR) due to incomplete PVD. METHODS: We prospectively evaluated the vitreoretinal relationships using high-resolution kinetic echography in 102 consecutive eyes of 100 patients with rhegmatogenous RD. In the first part, a case-control study was conducted to compare the vitreous status in patients with preoperative PVR (cases) with that in patients with non-PVR-complicated RD (controls). During the second part, patients with noncomplicated RD (65 eyes) who were operated on by a simple retinal attachment procedure were followed up for a mean period of 6.6 months to compare the recurrence of RD due to postoperative PVR according to their vitreous status. RESULTS: Patients with PVR on study entry had a higher prevalence of partial PVD (28 of 32 eyes, 87%) than did controls (25 of 70 eyes, 35%). The statistical significance of this difference was independent of all other variables studied. After a mean follow-up period of 6.6 months, the incidence of recurrence of RD associated with postoperative PVR was 33% in the eyes with incomplete PVD, compared with 4.9% in the eyes without incomplete PVD. CONCLUSIONS: Our results support the notion that the occurrence of incomplete PVD in RD is a significant risk factor for preoperative and postoperative PVR.
