How do you get Alpha-1?

Genetic disorders fall into several categories. Some are caused by a single mistake (mutation) in the DNA code. Disorders like Cystic Fibrosis, Sickle Cell Anaemia, Huntingtons and Alpha-1 are all caused by a single gene (obviously different single genes for each disorder) Others are caused by a combination of genetic mistakes.

Some disorders are "dominant" and others "recessive".

Huntingtons disease, which causes devastating destruction of the brain, is "dominant". This means if either of your parents have the disease then you have a 50/50 chance of having the faulty gene. If you have the faulty gene you will develop the disease. Alpha-1 and Cystic Fibrosis are examples of "recessive" genetic disorders. To have A1AD you have to have inherited the faulty gene from both parents.

What are chromosomes?

Chromosomes are tightly packed with long stands of DNA. We inherit 23 chromosomes from each parent, a total of 46 in all. It has been said that were we only to have one set of chromosomes we would die very rapidly as most "'sets" carry some mistakes. Having two sets means that if one particular chromosome is faulty then the corresponding one in the other "set" can do the job that the other cannot.

The gene that is responsible for giving the "orders" to manufacture AAT is on the long arm of chromosome 14. Some time, many thousands of years ago in Scandinavia a single person had a mutation of the chromosome 14 which caused the Alpha-1 protein to mis-fold. As this person had another chromosome 14 that produced normal AAT he wasn't affected. However, these were very different times and family members would interbreed. This faulty gene would have spread amongst the family and inevitably interbreeding would have resulted in people acquiring TWO faulty copies of the faulty gene. These people would have been the first to have A1AD.