What is cystic fibrosis classified as in terms of genetics?

Cystic fibrosis is classified as a homozygous recessive disease because it is caused by mutations in the CFTR gene located on chromosome 7. For an individual to express the disease, they must inherit two copies of the mutated gene, one from each parent. This means that both alleles at the CFTR gene locus must be recessive for cystic fibrosis to manifest.

Individuals who have one normal allele and one mutated allele are known as carriers; they do not exhibit symptoms of the disease but can pass the mutated allele to their offspring. Therefore, in the context of genetics, cystic fibrosis fits the criteria for a homozygous recessive condition, as it requires the presence of two copies of the mutated gene for the disease traits to appear. The other classifications mentioned, such as autosomal dominant or X-linked recessive, do not apply to cystic fibrosis due to the inheritance pattern associated specifically with this genetic condition.