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Biomedical subjects

D McGibbon

Publications and source records attributed to D McGibbon.

At least 19 recordsLinked to original sources

Mutation analysis in Irish families with glomuvenous malformations.

BACKGROUND: Glomuvenous malformations (GVMs) are rare bluish lesions that can affect the skin and mucosal surfaces. They represent defects in vasculogenesis. Lesions can occur sporadically or in an autosomal dominant mode of inheritance. Recent studies have shown that mutations in the glomulin gene (GLMN) on chromosome 1p21-22 are responsible for familial GVMs. OBJECTIVES: To search for mutations in GLMN in Irish families with GVMs. METHODS: We identified four Irish families with GVMs and confirmed linkage to chromosome 1p21-22 in these cases. We sequenced the glomulin gene in all affected and unaffected members of the families. Results Linkage analysis showed that affected individuals from the families shared a common haplotype. Mutation analysis revealed a delAAGAA mutation in exon 3 of the glomulin gene in all four families with GVMs. CONCLUSIONS: We confirm that mutations in the glomulin gene are responsible for GVMs and suggest a founder Irish mutation in the glomulin gene in four Irish families.

Adaptor Proteins, Signal Transducing↗

Comparison of assessments of severity and quality of life in cutaneous disease.

Clinicians are, by profession, capable assessors of severity of disease. Whether from severity they can deduce a patient's Quality of Life (QoL) is debatable. This study compared scores for physician-assessed severity with the corresponding scores for patient QoL, as assessed using Dermatology Life Quality Index (DLQI) questionnaires in 57 dermatological out-patients. Although there was some degree of correlation between the two measures (r = 0.56), interpretation of QoL from disease severity is clinically unreliable. Thus a physician's assessment of QoL requires formal assessment using a tool such as the DLQI.

Adolescent↗

Composite undergraduate clinical examinations: how should the components be combined to maximize reliability?

BACKGROUND: Clinical examinations increasingly consist of composite tests to assess all aspects of the curriculum recommended by the General Medical Council. SETTING: A final undergraduate medical school examination for 214 students. AIM: To estimate the overall reliability of a composite examination, the correlations between the tests, and the effect of differences in test length, number of items and weighting of the results on the reliability. METHOD: The examination consisted of four written and two clinical tests: multiple-choice questions (MCQ) test, extended matching questions (EMQ), short-answer questions (SAQ), essays, an objective structured clinical examination (OSCE) and history-taking long cases. Multivariate generalizability theory was used to estimate the composite reliability of the examination and the effects of item weighting and test length. RESULTS: The composite reliability of the examination was 0.77, if all tests contributed equally. Correlations between examination components varied, suggesting that different theoretically interpretable parameters of competence were being tested. Weighting tests according to items per test or total test time gave improved reliabilities of 0.93 and 0.81, respectively. Double weighting of the clinical component marginally affected the reliability (0.76). CONCLUSION: This composite final examination achieved an overall reliability sufficient for high-stakes decisions on student clinical competence. However, examination structure must be carefully planned and results combined with caution. Weighting according to number of items or test length significantly affected reliability. The components testing different aspects of knowledge and clinical skills must be carefully balanced to ensure both content validity and parity between items and test length.

Clinical Competence↗

A physical and expression map of the D17S1810-D17S1353 region spanning the central areolar choroidal dystrophy locus.

Central areolar choroidal dystrophy (CACD) causes bilateral irreversible central visual loss in the 5th to 7th decades. The authors previously described a large pedigree with the disorder, which showed linkage to chromosome 17p13.2-->p13.1 between microsatellite markers D17S1353 and D17S1810. 17p13 is very rich in genes that cause retinal diseases. We have now constructed a detailed and ordered physical map of the critical CACD region which spans up to 2.4 Mb. The new transcript map contains thirteen genes and seven expressed sequence tags (ESTs) that are eye-expressed, and therefore are positional candidates. Several of these have been screened, but no disease-causing mutations were found in CACD patients.

Blindness↗

Ullrich-Turner syndrome: seven pregnancies in an apparent 45,X woman.

A 37-year-old woman was referred for genetic counseling after termination of her probable seventh pregnancy. Ultrasound examination at 13 weeks of gestation had shown a fetus with bilateral cystic hygromas. A transabdominal amniocentesis confirmed 45,X karyotype in the fetus. The patient had marked short stature and a 45,X chromosome constitution in blood lymphocytes. Subsequently she had a hysterectomy and oophorectomy. Tissue of representative sites of the pathological specimen showed a 45,X chromosome constitution. However, molecular analysis of 8 sites from the uterus and ovaries, and of skin fibroblasts with X-chromosome microsatellites showed the presence of only one allele, except for the microsatellite DXS996 which demonstrated 2 alleles (155 bp and 161 bp) in ovarian tissue. The lymphocytes from the mother and her only son demonstrated the same single allele (161 bp). We conclude that molecular analysis of lymphocytes and of tissue is necessary for detecting low-level mosaicism in apparently homogeneous 45,X women.

Adult↗

Localisation of a gene for central areolar choroidal dystrophy to chromosome 17p.

Central areolar choroidal dystrophy (CACD) is a rare inherited retinal disease which causes progressive profound loss of vision in patients during their 4th decade. We have identified a Northern Irish family with 19 affected individuals in three living generations. We have performed a total genome search and established linkage of CACD in this family to chromosome 17p (multipoint Zmax = 5.65 at D17S938). The genes for phosphatidylinositol transfer protein (PITPN), retinal guanylate cyclase (GUC2D), beta-arrestin 2 (ARRB2), pigment epithelium-derived factor (PEDF) and recoverin (RCV1) map to this region and are candidate genes for retinal disease. Analysis of the coding region of the PITPN gene failed to reveal any mutation in this family.

Arrestins↗

Localisation of a gene for chondrocalcinosis to chromosome 5p.

Chondrocalcinosis is a common disorder which may associate with acute and chronic arthritis. A familial form, inherited as an autosomal dominant trait, has been mapped in a large family in which affected members also suffer recurrent fits in childhood. The gene which causes this disease shows linkage with several polymorphic markers on chromosome 5p with a maximum multipoint lod score of 4.6 between D5S810 and D5S416. Mapping a locus for chondrocalcinosis will allow the heterogeneity of the disorder to be assessed and may also be relevant to understanding the aetiology of osteoarthritis with which it commonly associates.

Child↗

[Diabetic cheirarthropathy simulating sclerodermia].

A patient with diabetic cheiroarthropathy in whom the diagnosis of sclerodermia had been initially made is reported. The initial diagnosis had resulted in inappropriate therapy. The clinical features of this poorly known complication of diabetes mellitus are reviewed, and the corresponding etiologic and pathogenetic hypotheses are discussed.

Adolescent↗

The nature of mycosis fungoides.

Thirty-four patients with a clinical diagnosis of plaque stage mycosis fungoides, poikiloderma atrophicans vasculare (poikiloderma) and parapsoriasis en plaques (parapsoriasis) were investigated for evidence of extracutaneous disease using a biochemical screen, blood films, bone marrow examination, chest radiograph, abdominal ultrasound, isotope liver scan, liver biopsy and lymphangiography. Skin biopsies were also taken from these patients and, in order to rule out non-specific histological change, from 29 controls with inflammatory skin disease; the slides were examined blind by two independent observers for evidence of mycosis fungoides or poikiloderma and graded accordingly. Both observers were able to differentiate significantly histological grades of mycosis fungoides corresponding to the clinical diagnosis although exact histological grades only corresponded on 35 per cent of slides. Features graded as classical or probable mycosis fungoides were found in between 22 and 67 per cent of patients with parapsoriasis and between 67 and 100 per cent of those with poikiloderma. We found no evidence of extracutaneous disease in any of our patients. Lymphangiograms were abnormal in 30 of 31 examinations but the changes were non-specific and did not correspond to disease type, duration or extent. Four patients had apparently unrelated co-existing disease including chronic lymphatic leukaemia in two, a monoclonal gammopathy and autoimmune haemolytic anaemia. This study shows that in its early stages mycosis fungoides is predominantly if not primarily a cutaneous disease. The findings also suggest that parapsoriasis and poikiloderma are part of the same disorder as mycosis fungoides or evolve into it. Aggressive treatment to prevent progression to mycosis fungoides plaque and tumour stage should therefore be tried. The findings support the idea that mycosis fungoides is a reactive rather than a neoplastic disorder.

Adolescent↗

Torre-Muir syndrome. An association with isolated sebaceous carcinoma.

Three cases of Torre-Muir syndrome are described in which isolated sebaceous carcinomas were associated with internal malignancy. The first was a 66-year-old woman who had a sebaceous carcinoma in association with carcinoma of the uterus, two adenocarcinomas of colon, carcinoma of renal pelvis and bladder, and a squamous cell carcinoma of the skin. The second was a 78-year-old woman who had a sebaceous carcinoma associated with carcinomas of the colon, ovary, and pancreas. The third patient had a sebaceous carcinoma associated with breast cancer. The subject is discussed and the previously reported cases reviewed.

Abdominal Muscles↗

Epidermal lipid biosynthesis in acne.

Lipid biosynthesis from glucose was increased in severe acne both in dermis and in epidermis which included the top portions of the pilosebaceous follicles. Both tissues retained their characteristic lipid labelling pattern. The magnitude of the increase in dermis and epidermis was similar, suggesting that epidermis may be subject to the same sebotrophic-lipogenic stimulus which affects sebaceous glands.

Acne Vulgaris↗