Abstract

LEAL, Alejandro; GUTIERREZ-ESPELETA, Gustavo  and  BARRANTES, Ramiro. Varios genes descartados como causantes de retinosis pigmentaria autosómica recesiva en dos familias costarricenses. Rev. costarric. cienc. méd [online]. 1998, vol.19, n.3-4, pp.194-205. ISSN 0253-2948.

In order to discard some candidate genes for autosomal recessive Retinitis Pigmentosa (RP), two families with this disease were studied. Linkage analysis was done, using polymorphic markers (STRPs). In one family (C1) affected members present an early onset and severe degeneration of the retina. In the other family (P1) the onset is earlier but the degeneration is slower than in C1. Phenotypic differences indicate that there are different mutations in both families. The following genes are not responsible for the disease in family C1 (Z (0.0)=: autosomal recessive RP (arRP) on 1q31-32.1, arRP by mutation in the PDEB gene on 4p16.3, arRP on 6p at 20 cM of peripherin gene, macular dystrophy on chromosome 6 and proto-oncogene myc. On the other hand, the marker RDS´ lod score certainly does not allow discard in a the peripherin gene as responsible (Z(0.1)= 0.0083), and there are positive lod scores for myc on 8q (Z (0.2)= 0.3050) and peripherin/RDS on 6p12 (Z(0.1)= 0.2063), but they are not significant. In the case of P1, results suggest that the following genes could be discarded: rodopsin, PDEB, arRP close to peripherhin, peripherin/RDS, adRP on chromosome 7 and myc. Nevertheless positive values were found near regions of rodopsin (RHO, Z(0.1)= 0.3991), peripherin (RDS, Z(0.2)= 0.3390) and Usher 1A on 14q (P1, Z(0.09)= 0.7647). The next step is to discard the regions with genes implicated in the visual transmission system or in the structure of the retina. This methodology can be used in Costa Rica for discarding genes implicated in other human hereditary diseases, for ascertaining information on the origen of certain pathologies, in order to get a precise diagnosis, to offer genetic counseling, and to support the design of therapies.

Keywords : Genética humana; Enfermedades hereditarias; Diagnóstico molecular; Análisis de ligamiento genético; Retinosis Pigmentaria; Marcadores polimórficos.