Molecular study of the rhodopsin gene in retinitis pigmentosa patients in the Basque Country.

Retinitis pigmentosa (RP) is a degenerative disorder affecting the outer segment of the retina and leading to night blindness and progressive visual field loss. The rhodopsin gene encodes a photolabile pigment located in the rod outer segments constituting around 80-90% of its protein content and is the initiation point for the visual cascade upon absorption of a single photon. Seventy-five unrelated, isolated RP families in the Basque Country, with at least one affected member, were diagnosed at our hospital after ophthalmic examination and electroretinogram analysis. The patients received genetic counselling according to their individual case based on their clinical diagnosis. The modes of inheritance found from pedigree studies were the following: 20% (15/75) were classified as autosomal dominant retinitis pigmentosa (ADRP), 17.33% (13/75) were autosomal recessive (ARRP), 2.66% (2/75) were unclassified (NC), and 60% (45/75) were sporadic cases (SCRP). From these families, 75 unrelated and affected index cases together with 22 affected relatives and 42 unaffected relatives were screened for mutations in the rhodopsin gene by GC clamped denaturing gradient gel electrophoresis. Our results showed that five ADRP, three ARRP, 15 SCRP, and one NC families had alterations in this gene. Only three of these alterations, that is 4% (3/75) (95% CL 0-8), appeared to be responsible for the disease. This represents a lower percentage than the 10% previously reported.

[Immunoproliferative small intestinal disease (IPSID): IPSID-like lymphomas, IPSID equivalents?, in 12 Spanish patients]. / Enfermedad inmunoproliferativa del intestino delgado (EIPID): linfomas "EIPID-símiles"--EIPID-equivalentes?--en doce pacientes españoles.

BACKGROUND: Immunoproliferative small intestine disease (IPSID) encompasses a primary intestinal lymphoma of underpriviliged populations of North Africa, Middle East, etc. This epidemiological feature strongly implicates environmental and host (genetic) factors in its pathogenesis. IPSID can be distinguished on clinicopathological grounds from "Western-type" intestinal lymphomas. "IPSID-like" lymphomas had been sporadically identified, i.e., patients with original clinico-analytical data of IPSID (chronic diarrhoea, malabsortion, clubbing of fingers, diffuse intestinal involvement, etc.) without its conventional histopathologic (lymphoplasmocytic or plasmocytic infiltration) and immunological (alpha-heavy-chain paraprotein) background. PURPOSE: The aim of this study has been: 1) to identify, in a series of small intestine lymphomas, a group of patients with a long-lasting history of chronic diarrhoea and a clinico-biologic pattern of "IPSID-like" lymphoma; 2) to analyze its clinicopathological profile; 3) to search for differences with the pattern of the remaining cases ("Western-type" lymphomas) and 4) To suggest a possible epidemiological significance. PATIENTS AND METHODS: Patients considered were 12 Spanish caucasians with primary intestinal lymphoma and a long-lasting history of chronic diarrhoea vs 31 cases of "Western-type" intestinal lymphomas admitted in our Hospital over a 33-year period. Statistical significance of differences in clinico-biological features (symptoms/signs, analytical data, patterns of involvement, histopathology, immunophenotype and tumor staging) between these two groups was evaluated using X2 test. RESULTS: The results of this retrospective study allow us to delineate a relatively homogeneous "IPSID-like" group (12 cases) among 43 cases of primary small intestine lymphoma diagnosed between 1960 and 1993. The clinico-pathological behavior of these patients was significantly different from that exhibited by the 31 cases of so-called "Western-type" lymphomas. CONCLUSIONS: It is suggested that they may represent a group of patients suffering an evanescent "IPSID-equivalent" disorder (last case diagnosed in 1975), that probably has evolved in similar but not identical epidemiological circumstances to those present in the "Third World" countries of our Mediterranean area.