[Molecular diagnosis of cystic fibrosis in 93 Argentinean patients and detection of heterozygotes in affected families. Impact on health services and therapeutic advances]. / Fibrosis quística: diagnóstico molecular en 93 pacientes argentinos y detección familiar de portadores. Impacto asistencial y proyección a nuevos avances terapéuticos.

INTRODUCTION: The cystic fibrosis is an autosomal recessive disease caused by more than 1500 mutations and variants in the cystic fibrosis transmembrane conductance regulator gene. OBJECTIVES: To establish the spectrum and frequency of mutations on this gene in Argentinean patients.To detect heterozygotes in affected families. PATIENTS AND METHODS: We investigated 91 clinical and biochemically confirmed patients with 2 elevated sweat tests and 2 sterile adults. We worked with 165 relatives. The molecular diagnosis was accomplished in 3 serial stages: a) determination of 29 frequent mutations; b) haplotypes for microsatellites; c) an extensive screening of gene through single strand conformation analysis and multiplex denaturing gradient gel electrophoresis with sequencing of abnormal patterns. Once patient's genotype was confirmed, we investigated the heterozygotes' state in the relatives. RESULTS: 1ST OBJECTIVE: Fourteen mutations were identified. Three more mutations were detected and other 11 mutations were characterized, 3 of them novel (p.G27R, c.622-2A>G, p.W277R). In total, we have identified 28 mutations responsible for 90.3% of the mutated alleles, 14 with a higher frequency than 1%. 2ND OBJECTIVE: From 165 investigated people, 143 were confirmed as heterozygotes and with normal genotype 22. CONCLUSIONS: This work contributed to the molecular characterization of patients with classic and atypical phenotypes and to the detection of great numbers of carriers. New pharmacological therapeutic investigations are based on the mutation type. Therefore, knowledge of patients, mutations (genotype) has significant importance for the future application of specific therapies.

Fibrosis quística: diagnóstico molecular en 93 pacientes argentinos y detección familiar de portadores. Impacto asistencial y proyección a nuevos avances terapéuticos / Molecular diagnosis of cystic fobrosis in 93 argentinean patients and detection of heterozygotes in affected families. Impact on health services and therapeutic advances

Introducción. La fibrosis quística es una enfermedad autosómica recesiva causada por más de 1.500mutaciones y variantes en el gen regulador de la conductancia transmembrana.Objetivos. Establecer el espectro y frecuencia demutaciones en este gen en pacientes argentinos.Detectar portadores en las familias involucradas.Material y métodos. Se investigó en 91 pacientes, clínica y bioquímicamente confirmados con 2 pruebas de sudor positivas y en 2 adultos estériles. Setrabajó con 165 familiares. El diagnóstico molecularcomprendió 3 etapas consecutivas: a) determinaciónde 29 mutaciones frecuentes; b) haplotipos por microsatélites; c) pesquisa completa del gen poranálisis conformacional de hebra simple y electroforesisen gel de gradiente desnaturalizante consecuenciamiento de los patrones anormales. Determinado el genotipo de los pacientes, se investigó elestado de portador en los familiares.Resultados. 1er Objetivo: Se identificaron 14 mutaciones, se detectaron otras 3 mutaciones y se caracterizaron otras 11 mutaciones, tres de ellas nuevas(p.G27R, c.622-2A>G, p.W277R). En total, se identificaron28 mutaciones responsables del 90,3 por ciento de losalelos mutados, 14 con una frecuencia superior al 1 por ciento2º Objetivo: De 165 personas investigadas, 143 fueronportadores y 22 con genotipo normal.Conclusiones. Este trabajo contribuyó a la caracterización molecular de pacientes con fenotipos clásicosy atípicos y a la detección de numerosos portadores.Las investigaciones fármaco-terapéuticas recientesse basan en el tipo de mutación. Por lo tanto,conocer las mutaciones de los pacientes (genotipo) tiene significativa importancia para la futura aplicaciónde terapias específicas.

Mutational spectrum of cystic fibrosis patients from Córdoba province and its zone of influence: implications of molecular diagnosis in Argentina.

Cystic Fibrosis (CF) is an autosomal recessive disorder affecting 1/2000-4000 newborns in Caucasian populations. This lethal disease mainly affects respiratory and digestive organs as well as fertility in man. So far, the CF prevalence and mutational spectrum have showed specificity among populations and regions, making it necessary to establish them in each one. In this study, we present the spectrum and frequency of CFTR gene mutations in CF patients from Córdoba (a province with 3.1 millions inhabitants in the middle of Argentina) and its zone of influence, to offer an accurate genetic testing. The study includes 78 families in which 98 patients fulfilled clinical criteria to CF diagnosis. The strategy for the molecular diagnosis comprised analysis of 21 common mutations, microsatellite haplotypes and the complete CFTR gene analysis using scanning techniques followed by sequencing of the abnormal migration patterns. Our first step led us to the identification of 10 mutations that represented 76% of alleles. Another four mutations (p.R1066C, c.1811 + 1.6 kbA > G, c.711 + 1G > T, and p.G85E) were found based on the microsatellite haplotype-mutation association. Finally, 14 mutations were characterized after the CFTR gene scanning, three of them are not previously described (p.G27R, c.622-2A > G, and p.W277R). In summary, we have identified 27 mutations accounting for 94.23% of CF alleles. This characteristic mutational spectrum highlights the 14 most frequent mutations (>1%) in the Córdoba region.