INBDE (Integrated National Board Dental Examination) Practice Exam 2026 - Free Practice Questions and Study Guide

Cystic fibrosis is an inherited disorder that affects the lungs, digestive system, and other organs. It is caused by a mutation in the gene that is responsible for producing a protein called cystic fibrosis transmembrane conductance regulator (CFTR). This protein helps in the movement of salt and water in and out of cells.

One of the most common symptoms of cystic fibrosis is high levels of chloride in sweat, which can be measured through a sweat test. This occurs because the mutated CFTR protein causes the body to produce thick and sticky mucus, which blocks the ducts of the sweat glands and leads to increased salt content in sweat.

Increased saliva production (option B) is not a common symptom of cystic fibrosis. Increased mucus production can occur in the airways, leading to difficulty breathing, but it does not affect saliva production.

Blood in the urine (option C) is not a symptom of cystic fibrosis. It can be a sign of a urinary tract infection or other underlying condition, but it is not directly related to cystic fibrosis.

Low sodium levels in the blood (option D) can be a complication of cystic fibrosis, but it is not a common