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Biomedical subjects

S Hodgson

Publications and source records attributed to S Hodgson.

At least 19 recordsLinked to original sources

Heritability of DNA-damage-induced apoptosis and its relationship with age in lymphocytes from female twins.

Apoptosis is a physiological form of cell death important in normal processes such as morphogenesis and the functioning of the immune system. In addition, defects in the apoptotic process play a major role in a number of important areas of disease, such as autoimmune diseases and cancer. DNA-damage-induced apoptosis plays a vital role in the maintenance of genomic stability by the removal of damaged cells. Previous studies of the apoptotic response (AR) to radiation-induced DNA damage of lymphoid cells from individuals carrying germline TP53 mutations have demonstrated a defective AR compared with normal controls. We have also previously demonstrated that AR is reduced as individuals age. Results from the current study on 108 twins aged 18-80 years confirm these earlier findings that the AR of lymphoid cells to DNA damage is significantly reduced with increasing age. In addition this twin study shows, for the first time, that DNA-damage-induced AR has a strong degree of heritability of 81% (95% confidence interval 67-89%). The vital role of DNA-damage-induced apoptosis in maintaining genetic stability, its relationship with age and its strong heritability underline the importance of this area of biology and suggest areas for further study.

Adolescent↗

Association between polymorphisms of the GPX1 gene and second primary tumours after index squamous cell cancer of the head and neck.

We investigated the association between genetic polymorphisms in GPX1 gene amongst patients who had index squamous cell carcinoma (SCCHN) and a second primary tumour (SPT) after a primary SCCHN in a case-control study. GPX1 genotypes were determined for 61 patients with SPT and for 259 control subjects by a PCR technique using a fluorescent-labelled primer. Analysis was by an ABI automated fluorescent sequencer. The associations between specific genotypes and the development of SPT were examined by logistic regression. A significant difference was found between the control group and the SPT cases in allele frequencies of GPX1 ALA( *)6 and ALA( *)7 (p(trend)=0.04). These results suggest that polymorphisms in the GPX1 gene may be a marker for SPT development and further studies are indicated.

Adult↗

An audit of screening for familial breast cancer before 50 years in the South Thames Region - have we got it right?

We have carried out an audit of breast screening by mammography under 50 years of age in a cohort of 192 women attending family cancer clinics run by the South Thames genetic services. Of these women, six came from families in which a BRCA mutation had been identified, 61 had > 50%, 35 a 20-50% and 90 had < 20% chance of carrying a high risk mutation. In the 192 women in the screened cohort, 9 breast cancers were diagnosed (4.7%), all in high-risk women. Three were diagnosed at the prevalence screen. Three were detected mammographically at subsequent screening rounds; three were detected by breast self-examination (BSE) between screening episodes. One interval cancer was visible on mammogram at presentation but not at screening five months previously. A second cancer was also visible on mammogram at presentation but the normal screening mammogram had been 17 months earlier, outside the recommended interval. The remaining interval cancer was not visible on the mammogram. A total of 363 two-view screening mammograms were performed in the 280 person-years of follow-up; 109 additional investigations were generated: 23 recall mammograms, 18 symptomatic mammograms, 45 ultrasounds, 12 aspiration cytologies and 11 biopsies. Cytology diagnosed malignancy in 1 of 12 cases; breast biopsy in 9 of 11 cases. Twenty-three additional women had ultrasound screening only. This audit suggests that screening below the age 50 years may be unnecessary in families with a low chance of having a BRCA1 or -2 mutation, but it is important to screen high-risk women at least annually and possibly under 35 years.

Adult↗

Excess risk of kidney disease in a population living near industrial plants.

Runcorn has been a site of chemical industry activity for over a century, where tons of toxic chemicals are released annually to air and water. Excess kidney disease mortality (nephritis, nephrotic syndrome, and nephrosis) was found in the population living within 2 km of the industrial plants (standardised mortality ratio (SMR) in males 131 (95% CI 90 to 185) and females 161 (95% CI 118 to 214)) compared to a reference population (northwest England)). Risk of hospital admissions for kidney disease in Halton (comprising the towns of Runcorn and Widnes) was higher than in the less industrial, nearby town of Warrington. The standardised admission ratio (SAR) in Halton was 115 (95% CI 107 to 124) for males and 126 (95% CI 117 to 137) for females; and in Warrington 91 (95% CI 85 to 97) for males and 84 (95% CI 78 to 91) for females compared to the Warrington and Halton area as a whole. The excess risk of kidney disease in the Runcorn area requires further investigation.

Chemical Industry↗

What motivates interest in attending a familial cancer genetics clinic?

The motivation of people who seek advice about a family history of cancer was explored in a cross sectional study of new cancer referrals to five regional cancer genetics centres in England: the PACT (patient and clinical team) psychosocial study. One hundred sixty-two people took part. Measures were source of referral, estimated and perceived cancer risk, level of cancer worry, and personal and family-centred reasons for wanting to be seen in clinic. General practitioners referred more people than hospital doctors, and referred a larger proportion of people at low genetic risk of developing cancer. More than half of the participants had been the first to raise the issue of their family history of cancer. Personal motivation for referral is clearly different for those who have had a diagnosis of cancer and for those with children, compared to unaffected and childless people, and is characterised by altruistic concern for other family members rather than a perception of increased personal risk. Men and people from ethnic minorities are very significantly under-represented. Understanding people's motivation may be useful in targeting genetic counselling for people with a family history of cancer.

Adult↗

Whole-gene APC deletions cause classical familial adenomatous polyposis, but not attenuated polyposis or "multiple" colorectal adenomas.

Familial adenomatous polyposis (FAP) is a dominantly inherited colorectal tumor predisposition that results from germ-line mutations in the APC gene (chromosome 5q21). FAP shows substantial phenotypic variability: classical polyposis patients develop more than 100 colorectal adenomas, whereas those with attenuated polyposis (AAPC) have fewer than 100 adenomas. A further group of individuals, so-called "multiple" adenoma patients, have a phenotype like AAPC, with 3-99 polyps throughout the colorectum, but mostly have no demonstrable germ-line APC mutation. Routine mutation detection techniques fail to detect a pathogenic APC germ-line mutation in approximately 30% of patients with classical polyposis and 90% of those with AAPC/multiple adenomas. We have developed a real-time quantitative multiplex PCR assay to detect APC exon 14 deletions. When this technique was applied to a set of 60 classical polyposis and 143 AAPC/multiple adenoma patients with no apparent APC germ-line mutation, deletions were found exclusively in individuals with classical polyposis (7 of 60, 12%). Fine-mapping of the region suggested that the majority (6 of 7) of these deletions encompassed the entire APC locus, confirming that haploinsufficiency can result in a classical polyposis phenotype. Screening for germ-line deletions in APC mutation-negative individuals with classical polyposis seems warranted.

Adenoma↗

Changes in psychological distress after cancer genetic counselling: a comparison of affected and unaffected women.

This study sought to examine changes in psychological distress following cancer genetic counselling. Women attending a family cancer clinic completed questionnaires before their appointment and at 2 weeks, 6 months and 12 months after their appointment. Twenty-six women were at low risk of developing breast or ovarian cancer, 76 were at moderate risk, 46 were at high risk and 46 women had previously had breast or ovarian cancer. All groups were compared with regard to measures of anxiety, depression, general psychological distress, worry about developing breast and ovarian cancer, and perceived risk of developing breast/ovarian cancer and perceived likelihood of carrying a genetic mutation. General psychological distress did not change over the course of the study and the groups did not differ on these measures. Worry about developing breast cancer and perceptions of the likelihood of carrying a genetic mutation significantly reduced following genetic counselling. On the whole women who had already had breast/ovarian cancer showed more concerns about ovarian cancer and raised perceptions of risk in comparison with the other groups, indicating the need for sensitive counselling of such women.

Anxiety↗

Familial breast cancer: an investigation into the outcome of treatment for early stage disease.

The purpose of this study was to retrospectively compare the outcomes of treatment in 304 women with familial and sporadic breast cancer to clarify the options for the primary management of familial breast cancer. The majority of women were consecutively ascertained on the basis of either breast cancer diagnosed at age < 40 years or bilateral breast cancer. In addition, known BRCA1 mutation carriers were identified through the genetics services in participating centres. These patients were subdivided into those with a significant family history of breast cancer or known BRCA1 mutation (FH+) and those with no significant family history (FH-). There were no significant differences in age, surgical treatment or adjuvant treatment between the two groups, but there were significantly more women whose nodal status was unknown in the FH+ group. Ipsilateral recurrence occurred in 22.2% of FH+ patients compared with 24.1% of FH- patients (p = 0.774) who underwent breast conserving surgery. There was a striking excess of contralateral breast cancers in the FH+ group (35.9% v 16%, p = 0.0007), with a cumulative risk of contralateral cancer of 36% at 10 years. This was reflected in a non-significant trend toward worse relapse free survival in the FH+ group (p = 0.0563), but no difference was observed in overall survival between the two patient groups (p = 0.142). Similarly, for patients with known BRCA1 mutations, contralateral recurrence occurred more frequently, but other outcomes were not significantly different from the FH- group. Breast conserving treatment is not associated with an increased risk of local recurrence in women with familial breast cancer and the prognosis of these women appears to be similar to that of young women with apparently sporadic breast cancer. However, the risk of contralateral breast cancer is significant in the FH+ group and should be considered in planning primary treatment and follow up.

Adult↗

The SPCH1 region on human 7q31: genomic characterization of the critical interval and localization of translocations associated with speech and language disorder.

The KE family is a large three-generation pedigree in which half the members are affected with a severe speech and language disorder that is transmitted as an autosomal dominant monogenic trait. In previously published work, we localized the gene responsible (SPCH1) to a 5.6-cM region of 7q31 between D7S2459 and D7S643. In the present study, we have employed bioinformatic analyses to assemble a detailed BAC-/PAC-based sequence map of this interval, containing 152 sequence tagged sites (STSs), 20 known genes, and >7.75 Mb of completed genomic sequence. We screened the affected chromosome 7 from the KE family with 120 of these STSs (average spacing <100 kb), but we did not detect any evidence of a microdeletion. Novel polymorphic markers were generated from the sequence and were used to further localize critical recombination breakpoints in the KE family. This allowed refinement of the SPCH1 interval to a region between new markers 013A and 330B, containing approximately 6.1 Mb of completed sequence. In addition, we have studied two unrelated patients with a similar speech and language disorder, who have de novo translocations involving 7q31. Fluorescence in situ hybridization analyses with BACs/PACs from the sequence map localized the t(5;7)(q22;q31.2) breakpoint in the first patient (CS) to a single clone within the newly refined SPCH1 interval. This clone contains the CAGH44 gene, which encodes a brain-expressed protein containing a large polyglutamine stretch. However, we found that the t(2;7)(p23;q31.3) breakpoint in the second patient (BRD) resides within a BAC clone mapping >3.7 Mb distal to this, outside the current SPCH1 critical interval. Finally, we investigated the CAGH44 gene in affected individuals of the KE family, but we found no mutations in the currently known coding sequence. These studies represent further steps toward the isolation of the first gene to be implicated in the development of speech and language.

Base Sequence↗

Allelic loss at SMAD4 in polyps from juvenile polyposis patients and use of fluorescence in situ hybridization to demonstrate clonal origin of the epithelium.

Juvenile polyposis syndrome (JPS; Online Mendelian Inheritance in Man2 174900) is a rare Mendelian disorder in which individuals have typical hamartomatous polyps within the gastrointestinal tract. The stromal element of the polyps has classically been thought to be the proliferative component, although epithelial malignancies (largely gastrointestinal cancers) occur more frequently than expected in JPS patients. Germ-line mutations in SMAD4 (DPC4) account for about a third of JPS cases. It has been postulated that the apparent paradox of a stromal lesion predisposing to epithelial malignancy can be resolved by the "landscaper" effect: an abnormal stromal environment affects the development of adjacent epithelial cells, and the resulting regeneration of damaged epithelium leads to an increased risk of cancer. We have found allele loss at the SMAD4 locus on 18q in polyps from JPS individuals with a germ-line SMAD4 mutation, showing that SMAD4 is acting as a tumor suppressor gene in JPS polyps, as it does in sporadic cancers of the gastrointestinal tract. Interphase fluorescence in situ hybridization showed deletion of one copy of SMAD4 in the epithelial component of JPS polyps, but not in the inflammatory infiltrate. Fluorescence in situ hybridization also suggested that a single copy of SMAD4 was present in stromal fibroblasts of JPS polyps. Thus, biallelic inactivation of SMAD4 occurs in both the epithelium and some of the stromal cells in these lesions, suggesting a common clonal origin. Epithelial malignancies almost certainly develop in juvenile polyposis through direct malignant progression of the epithelial component of the hamartomas. SMAD4/DPC4 probably acts as a "gatekeeper" tumor suppressor in juvenile polyps, and there is no need to invoke a "landscaper hypothesis."

Adenomatous Polyposis Coli↗

Support for linkage of autism and specific language impairment to 7q3 from two chromosome rearrangements involving band 7q31.

Childhood autism is characterised by impairments in communication and reciprocal social interaction together with restricted/stereotyped interests, which are evident before 3 years of age. Specific developmental disorders of speech and language (SDDSL) are characterised by impairment in the development of expressive and/or receptive language skills which is not associated with intellectual, sensory, physical, or neurological impairment. Family and twin studies indicate a substantial genetic component in the aetiology of both disorders. They also reveal increased rates of SDDSL in relatives of autistic individuals, suggesting that this phenotype can represent one manifestation of the genetic liability for autism. Modelling of the recurrence risk for autism and milder phenotypes, such as SDDSL, suggest that three or four epistatic loci may be aetiologically involved. A recently published linkage study of an exceptional family with an apparently dominantly inherited SDDSL implicated chromosome band 7q31 as the site of the putative susceptibility locus (SPCH1). This region of chromosome 7 also shows strong linkage in multiplex families with autism. We present two individuals (one has autism, the other SDDSL) with different, apparently balanced chromosome rearrangements involving a breakpoint at 7q31.3. Fluorescence in situ hybridisation was used to localise the breakpoints to an approximately 1 cM interval between CFTR and D7S643. Our findings may be of interest and relevance to the genetic aetiology of autism, and helpful in the search for susceptibility loci for SDDSL and autism. Am. J. Med. Genet. (Neuropsychiatr. Genet. ) 96:228-234, 2000.

Autistic Disorder↗

Comparison of fluorescent single-strand conformation polymorphism analysis and denaturing high-performance liquid chromatography for detection of EXT1 and EXT2 mutations in hereditary multiple exostoses.

EXT1 and EXT2 are two genes responsible for the majority of cases of hereditary multiple exostoses (HME), a dominantly inherited bone disorder. In order to develop an efficient screening strategy for mutations in these genes, we performed two independent blind screens of EXT1 and EXT2 in 34 unrelated patients with HME, using denaturing high-performance liquid chromatography (DHPLC) and fluorescent single-strand conformation polymorphism analysis (F-SSCP). The mutation likely to cause HME was found in 29 (85%) of the 34 probands: in 22 of these (76%), the mutation was in EXT1; seven patients (24%) had EXT2 mutations. Nineteen of these disease mutations have not been previously reported. Of the 42 different amplicon variants identified in total in the cohort, 40 were detected by DHPLC and 39 by F-SSCP. This corresponds to mutation detection efficiencies of 95% and 93% respectively. We have also found that we can confidently distinguish between different sequence variants in the same fragment using F-SSCP but not DHPLC. In light of this, and the similarly high sensitivities of the two techniques, we propose to continue screening with F-SSCP.

Chromatography, High Pressure Liquid↗