N-acetyltransferase 2 enzyme genotype-phenotype discordances in both HIV-negative and HIV-positive Nigerians

Non-compartmental and population pharmacokinetic analysis of dapsone in healthy NIGERIANS: A pilot study

Dapsone is employed for both non-dermatological and dermatological indications but with non-existent population pharmacokinetics (popPK) data in Nigerians. This study was therefore designed to develop a popPK model in Nigerians. Non-compartmental analysis and nonlinear mixed effects modelling were utilized for data analysis. Eleven participants administered 50 mg dapsone tablet were included in the analysis. Derived pharmacokinetic parameters were: Cmax  = 1.16 ± 0.32 μg/mL, Tmax  = 3.77 ± 2.40 h, and t1/2z  = 30.23 ± 11.76 h. PopPK model parameter estimates with inter-individual variability were Tlag = 0.40 h (10.0%, fixed); ka  = 1.78 h-1 (75.9%); V/F = 89.25 L (21.6%); and Cl/F = 1.32 Lh-1 (27.7%). Sex was significantly associated with Cl/F, and body weight with V/F. Best popPK model was one-compartment with lag time, and first-order absorption and elimination. Sex and body weight significantly influenced the clearance and distribution volume of dapsone respectively.

Pharmacogenomics of Allopurinol and Sulfamethoxazole/Trimethoprim: Case Series and Review of the Literature

Severe cutaneous adverse drug reactions (SCAR) such as the Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) and drug rash with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome (DIHS) can be induced by a plethora of medications. The field of pharmacogenomics aims to prevent severe adverse drug reactions by using our knowledge of the inherited or acquired genetic risk of drug metabolizing enzymes, drug targets, or the human leukocyte antigen (HLA) genotype. Dermatologists are experts in the diagnosis and management of severe cutaneous adverse drug reactions (SCAR) in both the inpatient and outpatient setting. However, most dermatologists in the US have not focused on the prevention of SCAR. Therefore, this paper presents a case series and review of the literature highlighting salient examples of how dermatologists can apply pharmacogenomics in the diagnosis and especially in the prevention of SCAR induced by allopurinol and sulfamethoxazole/trimethoprim, two commonly prescribed medications.

Evaluation of Genetic Polymorphisms of N-acetyltransferase 2 and Relation with Chronic Myeloid Leukemia

OBJECTIVES

The N-Acetyltransferase 2 (NAT2) gene encodes a key enzyme involved in xenobiotic metabolism, which contributes to the detoxification of numerous cancer therapy-induced products. However, the NAT2 genotype/phenotype is not fully understood and few studies have reported its relationship with CML. The aim of this study was to determine whether its polymorphisms (C481T, G590A, 803A>G and 857G>A) have a role in chronic myeloid leukemia susceptibility (CML) in Sudanese population.

METHODS

We performed a case- control study. DNA from 200 CML patients and 100 controls was analyzed for the NAT2 polymorphisms using PCR-RFLP assay.

RESULTS

The study showed NAT2 polymorphisms 803AG are associated with CML protection by a factor of 2.3, (OR = 0.044, 95% CI: 0.020-0.095, p = 0. 000). The study indicated that the heterozygous (GA) and mutant (AA) variants of the G857A genotype also offer protection, (OR = 0.002, 95% CI: 0.002-0.019, p = 0. 000) and (OR = 0.018, 95% CI: 0.002-0.133, p = 0. 000), respectively.

CONCLUSION

There was no significant difference in CML diagnosis among Sudanese cases with the 481C→T and 590G→A polymorphisms. But patients with the compound NAT2 genotypes 481CT/803 AG, 590AG/ 803AG, 590AG/ 803GG, 590AA/ 803AG and 590GG/ 803AG were found to have a reduced risk. The current study demonstrates that polymorphisms of NAT2 A803G and G857A might also act as protective factors against developing the disease.

Genotype-Environment Interaction Analysis of NQO1, CYP2E1, and NAT2 Polymorphisms and the Risk of Childhood Acute Lymphoblastic Leukemia: A Report From the Mexican Interinstitutional Group for the Identification of the Causes of Childhood Leukemia

Background: Acute lymphoblastic leukemia (ALL) is the main type of cancer in children. In Mexico and other Hispanic populations, the incidence of this neoplasm is one of the highest reported worldwide. Functional polymorphisms of various enzymes involved in the metabolism of xenobiotics have been associated with an increased risk of developing ALL, and the risk is different by ethnicity. The aims of the present study were to identify whether NQO1, CYP2E1, and NAT2 polymorphisms or some genotype-environmental interactions were associated with ALL risk in Mexican children.

Methods: We conducted a case-control study including 478 pediatric patients diagnosed with ALL and 284 controls (children without leukemia). Ancestry composition of a subset of cases and controls was assessed using 32 ancestry informative markers. Genetic-environmental interactions for the exposure to hydrocarbons were assessed by logistic regression analysis.

Results: The polymorphisms rs1801280 (OR 1.54, 95% CI 1.21–1.93), rs1799929 (OR 1.96, 95% CI 1.55–2.49), and rs1208 (OR 1.44, 95% CI 1.14–1.81) were found to increase the risk of ALL; being the risks higher under a recessive model (OR 2.20, 95% CI 1.30–1.71, OR 3.87, 95% CI 2.20–6.80, and OR 2.26, 95% CI 1.32–3.87, respectively). Gene-environment interaction analysis showed that NAT2 rs1799929 TT genotype confers high risk to ALL under exposure to fertilizers, insecticides, hydrocarbon derivatives, and parental tobacco smoking. No associations among NQO1, CYP2E1, and ALL were observed.

Conclusion: Our study provides evidence for the association between NAT2 polymorphisms/gene-environment interactions, and the risk of childhood ALL in Mexican children.