A 31-year-old man has been diagnosed with chronic obstructive pulmonary disease (COPD) as a result of being homozygous for the ZZ mutation of the -1 antitrypsin (AAT)gene alleles. His wife has been tested and has the MM genotype on her AAT gene alleles. The man is worried that his three children may eventually develop COPD. What is your best response?

Question

Quizplus · Accepted Answer

Although all of this man's children have inherited one mutated AAT allele from him, because his wife is not a carrier, the children are heterozygous for this mutation. The production of sufficient quantities of AAT is dependent on the inheritance of a pair of normal gene alleles because the AAT gene is recessive. When one of the pair of gene alleles is missing or mutated, and the other gene allele is normal, the person makes enough AAT to prevent COPD unless there is significant exposure to cigarette smoke and other precipitating factors. When two mutated alleles are inherited, COPD develops at a fairly young age even when the person is not exposed to cigarette smoke or other irritants.

A 31-Year-Old Man Has Been Diagnosed with Chronic Obstructive Pulmonary