In particular, oligo-symptomatic CFTR-RD (consequent to a moderate reduction of functionality, near the upper end of the 12–1% range), poly-symptomatic forms of CF with pancreas sufficiency or poly-symptomatic forms of CF with pancreas insufficiency (consequent to a great reduction of functionality, near the lower end of the 12–1% range) may arise. Here, CFTR is linked to cystic fibrosis.