F508del/L138ins compound heterozygotes do not have meconium ileus, CF-associated diabetes mellitus, severe liver damage and chronic Pseudomonas aeruginosa (Pseudomonas aeruginosa) infection is much less common than those who are homozygous for the most common pathogenic CFTR gene variant, F508del [19,20]. This evidence concerns the gene CFTR and intestinal obstruction in the newborn due to guanylate cyclase 2C deficiency.