1 copy of the PI*Z allele, the most common cause of Alpha-1 Antitrypsin Deficiency.
It has also been suggested in small studies that vasculitis may be more severe in patients positive for PiZ allele. [PMID 8889441]
A higher prevalence of the PiZ Allele has also been noted in some small studies of ANCA positive ulcerative colitis. [PMID 10579117]