How Is the Gene for Cystic Fibrosis Inherited?

Cystic fibrosis is inherited in an autosomal recessive pattern, which means that two copies of the cystic fibrosis gene in each cell are altered. In most cases, the parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene, but do not show signs and symptoms of the disorder.

When two cystic fibrosis carriers have a baby, the baby has a:

• One in four chance of inheriting two abnormal CFTR genes and having cystic fibrosis.
  
  
• One in four chance of inheriting two normal CFTR genes and not having cystic fibrosis or being a carrier.
  
  
• Two in four chance of inheriting one normal CFTR gene and one abnormal CFTR gene. The baby will not have cystic fibrosis, but will be a carrier like its parents.