In 2010, N. Derichts and co-workers performed ICM tests in 309 rectal biopsies from 130 infants, children and adults, including patients with known PI-CF (n = 34), PS-CF (n = 7), patients with an unclear diagnosis with mild CF symptoms, intermediate sweat test and/or CFTR variants screening (n = 61) and healthy controls (n = 28). The gene discussed is CFTR; the disease is cystic fibrosis.