Mukaddes AGIRTICI, Merve Nur TEKIN, Secahattin BAYAV, Esin Gizem OLGUN, Emine Semra KUCUK OZTURK, Nazan COBANOGLU
The Turkish Journal of Pediatrics - 2026;68(1):138-142
Background. Cystic fibrosis (CF) is a multisystem disease caused by variants in the CF transmembrane conductance regulator (CFTR) gene affecting ion transport. CFTR modulator therapy has become a significant treatment option for many CF patients. However, access to modulator therapy remains a challenge for cases with rare variants. Case Presentation. Our 9-year-old female patient, diagnosed with CF by elevated sweat chloride and history of steatorrhea from birth, carried the rare W1282X variant with no clear eligibility for modulator therapy. The family self-financed one month of elexacaftor / tezacaftor / ivacaftor (ETI) treatment. After one-month, clinical evaluation showed improvements in body mass index (BMI; 14.98 to 15.05 kg/m²), an increase in forced expiratory volume in 1 second (FEV1%) by 12% (72% to 84%), decreased sweat chloride levels (from 83 mEq/L to 9 mEq/L), and enhanced exercise capacity. No pulmonary exacerbations occurred during therapy. Based on these findings, modulator therapy approval was obtained for continued treatment. Our patient is currently 10 years old and has been on modulator therapy for approximately 12 months. Conclusions. Facilitating access to modulator therapies for patients with rare mutations is crucial, considering the potential long-term complications of CF. While organoid studies may not always predict clinical response, real-world cases demonstrate clinically meaningful benefit despite lack of organoid responsiveness. Short-term assessment of modulator response may not adequately reflect improvement in pulmonary function or exacerbation frequency, but decreases in sweat chloride, improvements in nutritional and functional parameters such as weight, BMI, and exercise capacity may be indicative of improvement in pulmonary function and exacerbation rates.
