Cystic fibrosis is caused by an __________________ gene.

Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which is located on chromosome 7. This gene is inherited in an autosomal recessive manner, meaning that an individual must inherit two copies of the mutated gene—one from each parent—to be affected by the disease.

In autosomal recessive inheritance, carriers of one copy of the mutated gene (heterozygotes) typically do not exhibit symptoms of the disease but can pass the gene to their offspring. For a child to develop cystic fibrosis, both parents must carry at least one copy of the mutated gene. This form of inheritance is distinct from other patterns such as autosomal dominant, where only one copy of the gene would be sufficient to cause the disease, or X-linked patterns, where the gene responsible would be located on the X chromosome.

Understanding the genetic basis of cystic fibrosis as an autosomal recessive condition is crucial for genetic counseling, screening, and treatment options for affected individuals and their families.