Final answer:
Cystic fibrosis is inherited as an autosomal recessive trait, where a child must inherit two copies of the recessive CFTR gene mutation to develop the disease. Carrier parents, who have one copy of the mutation, have a 25% chance of having a child with CF, even without a family history. Advances in medical treatment have increased life expectancy for those with CF.
Step-by-step explanation:
The genetic pattern that typically influences the development of cystic fibrosis (CF), especially in cases where there is no family history of CF, is that of an autosomal recessive trait. To have CF, the infant must inherit two recessive alleles, one from each parent, who are likely to be asymptomatic carriers of the CFTR gene mutation. Carriers, represented as Ff in genetic notation, have a 25% chance of passing on the disease to their offspring when both parents carry one defective allele.
CF is characterized by a mutation in the CFTR gene, leading to the production of thick mucus that can cause blockages in organs such as the lungs and intestines. This results in recurrent respiratory infections and malabsorption of nutrients. With medical interventions, people with CF can now live into their 30s or longer.
The inheritance pattern for cystic fibrosis can be exemplified using a Punnett square, where two carrier parents (Ff) could result in a child with CF (ff) with a 25% probability. Despite the possibility of such genetic diseases manifesting without a direct family history, carrier parents can pass the gene to their children.