CFTR and cystic fibrosis: While cystic fibrosis transmembrane conductance regulator (CFTR)-related exocrine pancreatic insufficiency is a primary driver of malnutrition in CF, multiple other factors, both directly and indirectly related to CFTR dysfunction, contribute to growth and nutritional status in this population [2] Highly effective CFTR modulator therapies (HEMT) are associated with robust weight gain in many people with cystic fibrosis (PwCF), and the mechanism of modulator-associated weight gain is likely multifactorial and variable at the individual patient level.