Dr Jenny Taylor
| Research Area: | Genetics and Genomics |
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| Technology Exchange: | Bioinformatics, Chromosome mapping and SNP typing |
| Keywords: | Translation, Genetics, clinical practice, genomics technologies and Oxford Biomedical Research Centre |
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Understanding how changes in genes cause disease is a fundamental objective of researchers at institutes such as the Wellcome Trust Centre for Human Genetics. However, before doctors can use this information for the benefit of patients, further work is required. We need to understand if the research discoveries are indeed useful for the diagnosis or treatment of medical conditions and we need to explore how new technologies can be adapted for routine use in the NHS. Genetics research most frequently results in new genetic tests for diagnosis of various conditions, but it can also change the way in which doctors treat disease or to the development of new pharmaceutical drugs.
The Oxford Biomedical Research Centre Genetics Theme, which is funded by the UK’s Department of Health, aims to bridge this gap between genetics research communities and doctors and healthcare professionals in the NHS. It is part of a broader programme being conducted by the Oxford BRC covering many disease areas including heart disease, cancer, stroke. The Genetics Theme focuses in particular on developing new technologies for the NHS. These include methods for sequencing the human genome. Although on the horizon, the cost of sequencing an individual’s complete DNA sequence is currently too high but the prospect of reading sections of it which we know relate to specific diseases is real – and may help us to diagnose and treat these diseases more effectively. We are also interested in new technologies that enable us to tell whether people have subtle changes to their DNA (mutations) or the amount present (copy number changes).
Our programme currently involves projects in heart disease, leukaemia, cancer, brain malformations and neurodegenerative conditions. We frequently seek participants for our studies. One active area of recruitment is for our brain malformations study.
There are no collaborations listed for this principal investigator.
2013. DNA polymerase ε and δ exonuclease domain mutations in endometrial cancer. Hum Mol Genet, 22 (14), pp. 2820-2828. Read abstract | Read more
Accurate duplication of DNA prior to cell division is essential to suppress mutagenesis and tumour development. The high fidelity of eukaryotic DNA replication is due to a combination of accurate incorporation of nucleotides into the nascent DNA strand by DNA polymerases, the recognition and removal of mispaired nucleotides (proofreading) by the exonuclease activity of DNA polymerases δ and ε, and post-replication surveillance and repair of newly synthesized DNA by the mismatch repair (MMR) apparatus. While the contribution of defective MMR to neoplasia is well recognized, evidence that faulty DNA polymerase activity is important in cancer development has been limited. We have recently shown that germline POLE and POLD1 exonuclease domain mutations (EDMs) predispose to colorectal cancer (CRC) and, in the latter case, to endometrial cancer (EC). Somatic POLE mutations also occur in 5-10% of sporadic CRCs and underlie a hypermutator, microsatellite-stable molecular phenotype. We hypothesized that sporadic ECs might also acquire somatic POLE and/or POLD1 mutations. Here, we have found that missense POLE EDMs with good evidence of pathogenic effects are present in 7% of a set of 173 endometrial cancers, although POLD1 EDMs are uncommon. The POLE mutations localized to highly conserved residues and were strongly predicted to affect proofreading. Consistent with this, POLE-mutant tumours were hypermutated, with a high frequency of base substitutions, and an especially large relative excess of G:C>T:A transversions. All POLE EDM tumours were microsatellite stable, suggesting that defects in either DNA proofreading or MMR provide alternative mechanisms to achieve genomic instability and tumourigenesis. Hide abstract
2013. Atypical phenotype associated with reported GCK exon 10 deletions: clinical judgement is needed alongside appropriate genetic investigations. Diabet Med, 30 (8), pp. e233-e238. Read abstract | Read more
Maturity-onset diabetes of the young (MODY) caused by heterozygous mutations in the glucokinase (GCK) gene typically presents with lifelong, stable, mild fasting hyperglycaemia. With the exception of pregnancy, patients with GCK-MODY usually do not require pharmacological therapy. We report two unrelated patients whose initial genetic test results indicated a deletion of GCK exon 10, but whose clinical phenotypes were not typical of GCK-MODY. Hide abstract
2013. Dual copy number variants involving 16p11 and 6q22 in a case of childhood apraxia of speech and pervasive developmental disorder European Journal of Human Genetics, 21 (4), pp. 361-365. | Read more
2013. Next-generation sequencing (NGS) as a diagnostic tool for retinal degeneration reveals a much higher detection rate in early-onset disease. Eur J Hum Genet, 21 (9), pp. 1031. Read abstract | Read more
Inherited retinal degeneration (IRD) is a common cause of visual impairment (prevalence ∼1/3500). There is considerable phenotype and genotype heterogeneity, making a specific diagnosis very difficult without molecular testing. We investigated targeted capture combined with next-generation sequencing using Nimblegen 12plex arrays and the Roche 454 sequencing platform to explore its potential for clinical diagnostics in two common types of IRD, retinitis pigmentosa and cone-rod dystrophy. 50 patients (36 unknowns and 14 positive controls) were screened, and pathogenic mutations were identified in 25% of patients in the unknown, with 53% in the early-onset cases. All patients with new mutations detected had an age of onset <21 years and 44% had a family history. Thirty-one percent of mutations detected were novel. A de novo mutation in rhodopsin was identified in one early-onset case without a family history. Bioinformatic pipelines were developed to identify likely pathogenic mutations and stringent criteria were used for assignment of pathogenicity. Analysis of sequencing metrics revealed significant variability in capture efficiency and depth of coverage. We conclude that targeted capture and next-generation sequencing are likely to be very useful in a diagnostic setting, but patients with earlier onset of disease are more likely to benefit from using this strategy. The mutation-detection rate suggests that many patients are likely to have mutations in novel genes. © 2013 Macmillan Publishers Limited All rights reserved. Hide abstract
2013. Germline mutations affecting the proofreading domains of POLE and POLD1 predispose to colorectal adenomas and carcinomas. Nat Genet, 45 (2), pp. 136-144. Read abstract | Read more
Many individuals with multiple or large colorectal adenomas or early-onset colorectal cancer (CRC) have no detectable germline mutations in the known cancer predisposition genes. Using whole-genome sequencing, supplemented by linkage and association analysis, we identified specific heterozygous POLE or POLD1 germline variants in several multiple-adenoma and/or CRC cases but in no controls. The variants associated with susceptibility, POLE p.Leu424Val and POLD1 p.Ser478Asn, have high penetrance, and POLD1 mutation was also associated with endometrial cancer predisposition. The mutations map to equivalent sites in the proofreading (exonuclease) domain of DNA polymerases ɛ and δ and are predicted to cause a defect in the correction of mispaired bases inserted during DNA replication. In agreement with this prediction, the tumors from mutation carriers were microsatellite stable but tended to acquire base substitution mutations, as confirmed by yeast functional assays. Further analysis of published data showed that the recently described group of hypermutant, microsatellite-stable CRCs is likely to be caused by somatic POLE mutations affecting the exonuclease domain. Hide abstract
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