
A1AT is inherited as an autosomal co-dominant genetic condition. Co-dominant genetic disorders occur when each inherited allele expresses some effect (like a lowered serum level of A1AT). In general, in a co-dominant condition, when the individual inherits two copies of an abnormal gene for the same trait, one from each parent, the risk of disease is higher than when only one abnormal allele is inherited.
Alpha-1 Antitrypsin Deficiency – Nord
This condition is inherited in an autosomal codominant pattern. Codominance
Genetics Home Reference"Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele usually will be expressed, while the effect of the other allele, called recessive, is masked. In codominance, ... means that two different versions of the gene may be active (expressed), and both versions contribute to the genetic trait.