Rapid HCP5 single-nucleotide polymorphism genotyping: A simple allele-specific PCR method for prediction of hypersensitivity reaction to Abacavir.

Clin Chim Acta. 2011 Apr 14;

Authors: Galván CA, Elbarcha OC, Fernández EJ, Beltramo DM, Soria NW

BACKGROUND: The most important factor limiting the success of an antiretroviral therapy is toxicity. The HLA-B*5701 allele is predictive of hypersensitivity reaction to Abacavir, and this gene is in a perfect linkage disequilibrium with the rs2395029 SNP present in the HCP5 gene. METHODS: Genomic DNA was extracted from blood obtained from 201 unrelated healthy Argentinean volunteers. The DNA was subjected to an allele-specific PCR method. Sequencing was performed to validate the test results. RESULTS: We were successful to amplify specific fragment of interest from the DNA samples. The method is easy, specific and reproducible. CONCLUSIONS: The application of this methodology is a rapid and simple method to detect the HCP5 polymorphism (rs2395029) previous to administration of Abacavir in patients with HIV infection.

PMID: 21514285 [PubMed - as supplied by publisher]

Single-nucleotide polymorphisms in HLA- and non-HLA genes associated with the development of antibodies to interferon-β therapy in multiple sclerosis patients.

Pharmacogenomics J. 2011 Apr 19;

Authors: Weber F, Cepok S, Wolf C, Berthele A, Uhr M, Bettecken T, Buck D, Hartung HP, Holsboer F, Müller-Myhsok B, Hemmer B

Interferons-β (IFN-β) are the most widely used immunomodulatory drugs for treatment of multiple sclerosis (MS). The development of neutralizing antibodies (NABs) against IFN-β is one of the main reasons for treatment failure. While formulation of the drug has a proven impact on the development of NABs, the genetic predisposition to develop antibodies is poorly understood. We performed genome-wide single-nucleotide polymorphism (SNP) genotyping in 362 MS patients of whom 178 had developed and 184 had not developed antibodies on IFN-β therapy. Four candidate SNPs were validated in an independent cohort of 350 antibody-positive and 468 antibody-negative MS patients. One SNP within the human leucocyte antigen (HLA) region (rs9272105, P-value: 3.56 × 10(-10)) and one SNP in an intergenic region on chromosome 8q24.3 (rs4961252, P-value: 2.92 × 10(-8)) showed a genome-wide significant association with the anti-IFN-β antibody titers. We found no interaction between the genome-wide significant SNPs (rs9272105 and rs4961252) in our study and the previously described HLA-DR(*)0401 or (*)0408 alleles, indicating an additive effect of SNPs and HLA alleles. Testing for these SNPs and the HLA-DR(*)0401 or (*)0408 alleles allows to identify patients at risk to develop antibodies to IFN-β and may provide helpful information for individual treatment decisions.The Pharmacogenomics Journal advance online publication, 19 April 2011; doi:10.1038/tpj.2011.14.

PMID: 21502966 [PubMed - as supplied by publisher]

[Detection of multiple Ophiocordyceps sinensis mutants in premature stroma of Cordyceps sinensis by MassARRAY SNP MALDI-TOF mass spectrum genotyping.]

Beijing Da Xue Xue Bao. 2011 Apr 18;43(2):259-266

Authors: Gao L, Li XH, Zhao JQ, Lu JH, Zhu JS

OBJECTIVE: To examine the mutants of Ophiocordyceps sinensis (Os) in the stroma of premature Cordyceps sinensis (Cs). METHODS: Used MassARRAY single nucleotide polymorphism (SNP) MALDI-TOF mass spectrum genotyping, designed eight SNP extension primers on the basis of the scattered, multiple point mutations of known Os mutants within their internal transcribed spacer (ITS) segments, and examined the Os mutant genotypes relating to the GC-biased Os genotype (gb #AB067721) in premature Cs stroma. RESULTS: The two AT-biased genotypes and the GC-biased Os were simultaneously detected in premature Cs stroma. SNP genotyping also detected at least two other Os genotypes of unknown sequences. CONCLUSION: Coexistence of the three known Os genotypes indicates the existence of possible transition point mutations within Os genes during germination and early maturation of Cs. Simultaneous detection of at least two unknown genotypes coexisting with those known mutants possibly evidences the transversion mutations within Os genes.

PMID: 21503123 [PubMed - as supplied by publisher]

Pyrethroid resistance in Sitophilus zeamais is associated with a mutation (T929I) in the voltage-gated sodium channel.

Insect Mol Biol. 2011 Apr 18;

Authors: Araújo RA, Williamson MS, Bass C, Field LM, Duce IR

The maize weevil, Sitophilus zeamais, is the most important pest affecting stored grain in Brazil and its control relies heavily on the use of insecticides. The intensive use of compounds such as the pyrethroids has led to the emergence of resistance, and previous studies have suggested that resistance to both pyrethroids and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) may result from reduced sensitivity of the insecticide target, the voltage-gated sodium channel. To identify the molecular mechanisms underlying pyrethroid resistance in S. zeamais, the domain II region of the voltage-gated sodium channel (para-orthologue) gene was amplified by PCR and sequenced from susceptible and resistant laboratory S. zeamais strains that were selected with a discriminating dose of DDT. A single point mutation, T929I, was found in the para gene of the resistant S. zeamais populations and its presence in individual weevils was strongly associated with survival after DDT exposure. This is the first identification of a target-site resistance mutation in S. zeamais and unusually it is a super-kdr type mutation occurring in the absence of the more common kdr (L1014F) substitution. A high-throughput assay based on TaqMan single nucleotide polymorphism genotyping was developed for sensitive detection of the mutation and used to screen field-collected strains of S. zeamais. This showed that the mutation is present at low frequency in field populations and is a useful tool for informing control strategies.

PMID: 21496128 [PubMed - as supplied by publisher]