CYP1B1 and pulmonary arterial hypertension: CYP1B1 over-expression has been observed in PASMCs fromboth idiopathic and hereditary PAH patients, and various SNPs in CYP1B1 havebeen associated with increased disease penetrance.8,122 Conversely, Epstein-Barrvirus (EBV)-immortalized B cells cultured from female HPAH patients have 10-foldlower expression of CYP1B1 than control groups.