Identification of Acute Intermittent Porphyria Modifying Genes

Inclusion Criteria: * Willing and able to give informed consent * 12 years of age or older * Willingness to provide blood/saliva and urine samples, and clinical information * A member of an AIP family, defined as (must meet one of the following): 1. proband: possesses an AIP pathogenic mutation and is/has been symptomatic (experienced acute attacks in the opinion of the investigator) 2. Parents (no known HMBS mutations or heterozygote with familial mutation) 3. First, second, or third degree relative of (a) or (b)