Cystic fibrosis is the most common autosomal recessive genetic defect of one gene CFTR, where a variety of mutations were revealed. Cystic fibrosis is a variable disease and to date the genotype-phenotype correlation is difficult to clarify. The aim of the study was to analyse retrospectively the genotype and phenotype of children with cystic fibrosis and to search the correlation between type of mutation in CFTR and clinical manifestation of the gastrointestinal tract.
Material and methods: The study group comprised 52 patients. Molecular DNA analyses were performed in 43 cases. Statistical analysis was done by using Fisher test.
Results: In 34 (79%) cases two mutations in the CFTR gene were identified. In this group 21 cases were identified as a homozygous for AF508 mutation, in single case other mutations were found. A mutation of one CFTR allel was revealed in 11 patients, cystic fibrosis was not confirmed by genetic test in 9 children. Mean age of diagnosis was 34 months. In 38 children (73%) pancreatic insufficiency in the course of disease was found. Exocrine insufficiency of pancreas was showed significant frequently in homozygous group. Liver dysfunction in 20 children (38.5%) was revealed. In this group 12 patients was identified as a homozygous for deltaF508 mutation. On the base of oral glucose tolerance test the diabetes mellitus and glucose intolerance was diagnosed in 4 cases with homozygous genotype. Seven patients died in the endstage of the illness, in two of them homozygous mutation deltaF508 was found, in next 5 patients genetic analysis was not performed.
Conclusions: The frequency and severity of clinical manifestation of the gastrointestinal tract correlates with deltaF508 mutation. Early genetic test and demonstration of molecular defect in CFTR gene confirms the clinical diagnosis of cystic fibrosis and improves a quality of life and prolongs survival time of cystic fibrosis patients.