PT - JOURNAL ARTICLE AU - Guergana Petrova AU - Nadezhda Yaneva AU - Malgorzata Libik AU - Dimitrinka Miteva AU - Boriana Gospodinova AU - Margarita Nikolova AU - Penka Perenovska AU - Milan Macek Jr AU - Alexey Savov TI - Clinical presentation in CF patients with large deletions AID - 10.1183/13993003.congress-2020.2767 DP - 2020 Sep 07 TA - European Respiratory Journal PG - 2767 VI - 56 IP - suppl 64 4099 - http://erj.ersjournals.com/content/56/suppl_64/2767.short 4100 - http://erj.ersjournals.com/content/56/suppl_64/2767.full SO - Eur Respir J2020 Sep 07; 56 AB - Introduction: Cystic fibrosis (CF) is polyorgan life-threatening disease with variable clinical presentation according the genetic status of the patient. The disease is associated with at least one mutation on each allele on CF transmembrane conductance regulator (CFTR). After screening for point mutations and small indel, using Sanger sequencing and NGS, in some patients the second mutation remains unidentified unless we use MLPA.Materials and Methods: In a group of 44 CF patients with only one mutation we performed MLPA analysis for detection of large deletions and duplications in CFTR gene using P091 MLPA kit.Results: The MLPA screening of CFTR gene detected large deletions in eight patients (18%): deletion of exons 4-11 in one patient with p.R1158X mutation, deletion of exons 18-20 in three patients with F508del mutation and in one with p.R334W, deletion of exons 2 and 3 in two patients with F508del, two deletions of exons 2 and 13 in one patient. The last finding is novel and not described in databases. The clinical presentation of CF in all of them was with early onset (in the first year of life), meconium ileus (in 1), failure to thrive (in 8), pancreatic insufficiency, obstructive lung disease (in 8) and abnormal sweat test levels (3 borderline and 5 over 60 mEq/l).Conclusion: It can be assumed that deleted alleles account for about 1% of molecular defects in our patients and therefore they are not so rare. The clinical presentation of those patients was with early onset and require prompt therapy. In countries without NBS, early diagnosis could be challenging, especially in children with borderline sweat tests. Therefor it is suitable to use MLPA of CFTR gene for routine molecular diagnosis of CF.FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 2767.This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).