Novel cytochrome P450-2D6 promoter sequence variations in hepatitis C positive and negative subjects.

INTRODUCTION: CYP2D6 is a liver enzyme that metabolizes more that 25% of drugs and thus may play a pivotal role in drug-drug interactions. The promoter sequences of cytochrome P450 2D6 (CYP2D6) gene could impact metabolic activity. METHODS: We analyzed genetic variations in the promoter sequence of CYP2D6 gene for 71 hepatitis C negative and 15 hepatitis C positive subjects. RESULTS: We found two novel genetic variants -1822A→G; -1740C→T, only in two patients with hepatitis C. Also, two linked new promoter sequence variations at -2060 G→A and -2053 T→G nucleotide positions that present in both hepatitis C negative and positive subjects are identified. The -2060 and -2053 variations are confirmed to be in linkage disequilibrium. The individuals with -2060A/A, and -2053G/G variation appeared to be associated with significantly lower levels of liver CYP2D6 mRNA. Analysis of CYP2D6 enzymatic activity in *1/*1 (wild type) subjects revealed that hepatitis C positive subjects expressed about 2.6-fold lower activity (24.0 ± 1.5 vs. 62.6 ± 3.7 pmol/min/mg; p = 0.0061) relative to hepatitis C negative. CONCLUSION: These data suggest that promoter variations -1822A→G and -1740C→T are present only in hepatitis C infected subjects. Hepatitis C positive individuals were associated with a lower liver CYP2D6 enzyme activity.

Adverse events with rhGH treatment of patients with chronic renal insufficiency and end-stage renal disease.

OBJECTIVE: Recombinant human growth hormone (rhGH) has been used to improve the growth retardation associated with chronic renal insufficiency (CRI) and end-stage renal disease. We determined the incidence of one of four targeted adverse events (AEs): malignancy, slipped capital femoral epiphysis (SCFE), avascular necrosis (AN), and intracranial hypertension (ICH). STUDY DESIGN: During a 6.5-year period, we prospectively assessed patients enrolled in the CRI, dialysis, and transplant registries of the North American Renal Transplant Cooperative Study. The availability of an untreated control population facilitated determining whether or not there was the association between the AE and rhGH treatment. RESULTS: Of the targeted AE, the only significant relation with rhGH treatment was the presence of ICH in patients with CRI; however, in all 3 instances, ICH occurred 2, 50, and 1131 days after discontinuation of rhGH. Considering that the mechanism of ICH in rhGH-treated patients is thought to be increased CSF production, rhGH probably had no role in the development of ICH in at least 2 of the 3 patients with CRI. A number of nontargeted AE were identified that have been associated with rhGH treatment in patients without renal disease. The incidence of glucose intolerance, pancreatitis, progressive deterioration of renal function, acute allograft rejection, and fluid retention were not more frequent in those receiving rhGH treatment compared with the control population. CONCLUSIONS: This report validates the importance of a control population in ascribing AE to any therapeutic intervention. Previously identified AE associated with rhGH treatment are infrequent in patients with CRI and end-stage renal disease.