CFTR and cystic fibrosis: In addition, studies on both CF animal models and CF patients suggest that besides the CFTR gene mutation, other defects such as altered activity of various membrane cation transport systems [2], [3], abnormal membrane phospholipid composition, elevated turnover of essential fatty acids (EFAs) [7], [10]–[13] and oxidant-antioxidant imbalance, can contribute to clinical manifestations of CF [14]–[17].