Niejednoznaczna diagnoza mukowiscydozy u dzieci z pozytywnym wynikiem badania przesiewowego

Introduction The implementation of newborn screening for cystic fibrosis enabled early diagnosis and treatment of this disease. The diagnosis of cystic fibrosis occurs when there is a significantly elevated concentration of chloride in the sweat or CF-causing mutations are present in both alleles of the CFTR gene. CFSPID (Cystic Fibrosis Screen Positive Inconclusive Diagnosis) corresponds to a situation when CF cannot be either diagnosed or clearly ruled out. Objective The aim of this study was to present the characteristics of children with abnormal screening in whom it was impossible to recognize or rule out cystic fibrosis. Methods The study included patients with abnormal newborn screening test, performed by the Institute of Mother and Child from 01.09.2006 until 30.09.2014, born in four provinces, which were under our further care, and who met criteria of CFSPID. Results During the period of study, the diagnosis of cystic fibrosis was established in 142 patients. In 75 patients, not only was cystic fibrosis not diagnosed but also it could not be clearly ruled out. The number of such children has increased significantly after 2010. In the study group, the mean value of sweat chloride concentration was 26.6 ± 9.6 mmol/l. In every patient, two mutations in the CFTR gene were detected. Sixty-eight children (90%) had a cystic fibrosis causing mutation in one allele and a CFTR -related disorder causing mutation or the one with uncertain clinical consequences on the other allele. Conclusions The introduction of CF NBS has not only enabled early diagnosis of CF, but has also helped to detect changes in the CFTR with unclear clinical consequences. Changes are necessary, in order to reduce the detection of mutations of unclear phenotypic consequences.