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Biomedical subjects

Owen Smith

Publications and source records attributed to Owen Smith.

8 recordsLinked to original sources

A novel primary immunodeficiency with specific natural-killer cell deficiency maps to the centromeric region of chromosome 8.

We describe four children with a novel primary immunodeficiency consisting of specific natural-killer (NK) cell deficiency and susceptibility to viral diseases. One child developed an Epstein-Barr virus-driven lymphoproliferative disorder; two others developed severe respiratory illnesses of probable viral etiology. The four patients are related and belong to a large inbred kindred of Irish nomadic descent, which suggests autosomal recessive inheritance of this defect. A genomewide scan identified a single 12-Mb region on chromosome 8p11.23-q11.21 that was linked to this immunodeficiency (maximum LOD score 4.51). The mapping of the disease-causing genomic region paves the way for the identification of a novel pathway governing NK cell differentiation in humans.

Chromosome Mapping↗

Characterization of the t(17;19) translocation by gene-specific fluorescent in situ hybridization-based cytogenetics and detection of the E2A-HLF fusion transcript and protein in patients' cells.

This is the first report to comprehensively characterize the E2A-HLF fusion generated from the t(17;19)(q22;p13) translocation in childhood B-lineage acute lymphoblastic leukemia. E2A gene rearrangement and E2A-HLF transcript and protein expression were determined using conventional cytogenetics, fluorescent in situ hybridization, reverse transcriptase polymerase chain reaction and Western blotting in leukemic cells from three patients.

Adolescent↗

Modelling infectious disease transmission with complex exposure pattern and sparse outcome data.

We present a regression modelling framework to analyse infectious disease transmission during a time period where extensive exposure data are available, but where the outcome data are sparse. A latent variable model is used for each exposure time, allowing a straight-forward accumulation of risk for a collection of exposures for which outcome data are available. We describe an analysis of HIV infection from blood products among a cohort of haemophiliacs in Ireland between 1980 and 1985. The analysis provides estimates of the time pattern and batch effects; we show how analytical complexity such as smoothly varying coefficients or random coefficient models can be accommodated by the model. Finally, we discuss other problems where the model is applicable.

Cohort Studies↗

Natural history of GATA1 mutations in Down syndrome.

Acquired mutations in megakaryocyte transcription factor GATA1 have recently been reported in Down syndrome (DS), transient myeloproliferative disorder (TMD), and acute megakaryoblastic leukemia (AMKL). To provide novel insight into GATA1 mutations in DS, genomic DNA was assayed from 12 AMKL and 4 TMD cases (including neonatal, prediagnosis samples in 4 of 16), neonatal blood spots from 21 DS children without clinically evident TMD or AMKL, and 62 non-DS cord blood samples, using techniques not previously employed with such samples. GATA1 mutations were present in all TMD and AMKL cases and at birth in 3 of 4 children without known clinical TMD, who later developed AMKL. They were present at birth in 2 of 21 DS neonates, who have not yet, but could still, develop AMKL (now 26 and 31 months). GATA1 mutations were not detected in 62 non-DS cord blood samples. In 4 AMKL patients multiple independent GATA1 mutations were observed. These data show GATA1 mutations occur in utero in most DS TMD and AMKL, that they may occur without clinical signs of disease, and that multiple separate GATA1 mutant clones can occur in an individual. The findings have implications for pathogenesis of DS TMD and AMKL and highlight parallels between DS AMKL and other childhood leukemias.

Child, Preschool↗

Cytokine gene polymorphisms: association with psoriatic arthritis susceptibility and severity.

OBJECTIVE: To determine whether functional cytokine gene polymorphisms influence disease susceptibility and phenotype in patients with psoriatic arthritis (PsA). METHODS: DNA was obtained from 147 PsA patients and 389 controls. Seven functional proinflammatory (interleukin-1beta [IL-1beta] +3953, IL-6 -174, tumor necrosis factor alpha [TNFalpha] -308, TNFbeta +252) and antiinflammatory (IL-10 -1082, IL-10 -592, IL-1 receptor antagonist [intron 2, 86 bp, variable-number tandem repeat]) gene polymorphisms were detected by polymerase chain reaction and restriction fragment length polymorphism assays. RESULTS: No significant difference in genotype frequencies was observed between the control and the PsA patient populations, and no association with Steinbrocker functional class, disease classification (polyarticular or oligoarticular), presence of spinal involvement, or age at PsA onset was observed. The presence of joint erosions was significantly associated with the TNFalpha -308 and TNFbeta +252 polymorphisms (P < 0.0001 and P = 0.0017, respectively). Frequencies of the TNFalpha -308 and TNFbeta +252 genotypes were also significantly different (P = 0.0078 and P = 0.0486, respectively) in a group of progressors (patients with early PsA in whom the number of joint erosions in the hands and feet increased over a median interval of 24 months) compared with a group of nonprogressors. Age at psoriasis onset was significantly associated with the TNFbeta +252 and TNFalpha -308 polymorphisms (P = 0.0003 and P = 0.0081, respectively). The TNFB2B2 and TNFalpha -308 AA genotypes were associated with the earliest mean ages at psoriasis onset. CONCLUSION: The TNFalpha -308 and TNFbeta +252 polymorphisms were significantly associated with age at psoriasis onset, presence of joint erosions in PsA, and progression of joint erosions in early PsA. TNF gene polymorphisms may be useful prognostic markers in PsA, and these results support the rationale for using anti-TNF treatment in patients with severe, progressive PsA.

Adolescent↗

Dentoalveolar trauma in a patient with chronic idiopathic thrombocytopenic purpura: a case report.

A case is presented of a 13-year-old boy with chronic idiopathic thrombocytopenic purpura (ITP) who sustained traumatic labial luxation of both lower central incisors, with partial alveolar fracture resulting in displacement of the labial alveolar plate. Intravenous immunoglobulin (Fleibogamma, 1 g/kg body weight x 2 days) was administered, resulting in the patient's platelet count rising from 15,000/mm3 to 70,000/mm3. Under general anesthesia, the displaced lower labial alveolus and luxated teeth were repositioned and splinted 2 days following trauma. Healing was uneventful. Subsequently, both lower central incisors became nonvital and were endodontically treated. The dental treatment of this patient with ITP is discussed in terms of emergency management, and subsequent care.

Adolescent↗