Acute intermittent porphyria
Causes
What gene change causes acute intermittent porphyria?
A change/mutation in the gene HMBS causes acute intermittent porphyria. The genetic change makes an enzyme known as hydroxymethylbilane synthase (HMBS) work less than usual. This enzyme is also know as porphobilinogen deaminase (PBGD). This is the only gene known to cause acute intermittent porphyria and is located on chromosome 11.
Acute Intermittent Porphyria. Gene Reviews. (http://www.ncbi.nlm.nih.gov/books/NBK1193)