Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 4 uppsatser.

Familial lipoprotein lipase (LPL) deficiency is a rare disorder of lipid metabolism associated with massive chylomicronaemia. Patients often present early in life with abdominal pain, pancreatitis, hepatosplenomegaly, eruptive xanthomata and zero to near zero levels of LPL activity in post-heparin plasma. The genetic heterogeneity underlying this disease is well-characterised and over 40 mutations have been described at the LPL gene loci. In this report three mutations are described at the LPL locus in two unrelated probands, namely, JJ (Kindred I) and LB (Kindred II). JJ presented early in childhood with signs and symptoms suggestive of LPL-deficiency. These were abdominal pain, hepatosplenomegaly and a markedly reduced LPL activity (38% of normal) in post-heparin plasma. DNA studies showed JJ to be a compound heterozygote for two point mutations in the LPL gene, these being, the I194T and C418Y substitutions, which occur in exons 5 and 9, respectively. Several mutation detection systems were set up as part of the characterisation and screening workup for these mutations; these were, allele-specific oligo nucleotide (ASO) hybridisation, "ARMS" PCR, PCR-SSCP, RT-PCR and DNA sequence analysis. In an earlier separate study, in vitro transfection results showed that the I194T mutant was catalytically inactive. Our findings of zero LPL activity in JJ's post-heparin plasma, implies that the C418Y mutation is also likely to produce an inactive protein product. The differences in LPL activity observed during the pre- and post-pubertal stages, if not artefactual, may be due to differential processing of LPL during human development with loss of activity post puberty. LB was first diagnosed with pancreatitis during the third trimester of her pregnancy. Although her child, BB, was successfully delivered by caesarean section, LB died of haemorrhagic pancreatitis with the marked hyperlipidaemia being suggestive of an underlying deficiency in LPL activity. Genomic DNA from her parents was first subjected to mutation analysis, since only slide specimens of post-mortem material were available from LB. Maternal DNA revealed a 0-A transition at nucleotide position 1516 which results in the substitution of lysine for glutamic acid at codon 421 in exon 9 (E421K), while paternal DNA show a single polymorphism at codon 108 in exon 3 of the LPL gene. Analysis of archival DNA obtained from histopathological slides of spleen tissue from LB also showed the E421K mutation. This mutation was also detected in her offspring, BB indicating maternal inheritance in three generations. While, this mutation may produce a catalytically defective product, the evidence is insufficient to propose a role for LPL deficiency as the primary cause of death in this patient, hence the search for a second mutation in the LPL gene of LB is imperative to establish this association.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2007. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [104]-114).

by Chiu Wing Lok Abe Kurtz. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 218-230). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Thesis (Ph. D.)--University of Virginia, 2007. / Includes bibliographical references. Also available online through Digital Dissertations.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [115]-121).

Orientador: Maria Marluce dos Santos Vilela / Dissertação (mestrado) - Universidade Estadual de Campinas. Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-15T09:35:25Z (GMT). No. of bitstreams: 1 Ramalho_VanessaDomingues_M.pdf: 1157730 bytes, checksum: 0cd719050713e1b2340be47d4d5f5b38 (MD5) Previous issue date: 2010 / Resumo: A agamaglobulinemia ligada ao X (XLA; OMIM#300755) é uma imunodeficiência primária humoral caracterizada por um bloqueio na diferenciação dos linfócitos B na medula óssea, levando à profunda hipogamaglobulinemia e reduzido número ou ausência de células B periféricas. Os pacientes com XLA são susceptíveis a infecções recorrentes por bactérias encapsuladas e enterovírus devido à deficiência de anticorpos. Mutações no gene codificante da tirosina quinase de Bruton (Btk) são responsáveis pela doença. Btk é uma tirosina quinase citoplasmática da família Tec importante no desenvolvimento, na diferenciação e na sinalização dos linfócitos B. A detecção de mutações no gene btk possibilita o diagnóstico definitivo de XLA. O objetivo deste estudo foi identificar e caracterizar mutações em btk. Foram incluídos 6 pacientes conforme os critérios do PAGID e ESID: indivíduos do sexo masculino com menos de 2% de linfócitos B periféricos, hipogamaglobulinemia e história de infecções bacterianas de repetição. A triagem de mutações foi realizada com a técnica de SSCP e possíveis mutações foram confirmadas por seqüenciamento. A expressão de Btk nos pacientes e mães foi avaliada em monócitos por citometria de fluxo. Dentre os pacientes analisados as principais manifestações clínicas foram as infecções do trato respiratório. Todos tiveram início dos sintomas durante o primeiro ano de vida, linfócitos B periféricos abaixo de 2% e hipogamaglobulinemia anterior ao início da terapia de reposição de imunoglobulinas. Foram identificadas cinco mutações em btk, três novas (p.Ala347fsX55, p.I355T e p.Thr324fsX24) e duas já descritas na literatura (p.Q196X e p.E441X). A detecção das mutações nos pacientes permitiu a análise mutacional de mães, avós e tias maternas. Três mães e uma avó foram confirmadas portadoras de XLA. Em adição, os valores de expressão de Btk obtidos mostraram deficiência da proteína (4,5% a 65,2%) nos pacientes e um padrão bimodal de expressão de Btk foi observado nas mães, indicando o estado de portadora de XLA. Em um dos pacientes não foi identificada mutação, entretanto a expressão de Btk mostrou-se reduzida. O uso combinado da análise genética e da avaliação da expressão de Btk por citometria de fluxo possibilitou o diagnóstico definitivo de XLA e a identificação de portadoras da doença. / Abstract: X-linked agammaglobulinemia (XLA; OMIM# 300755) is a primary humoral immunodeficiency characterized by a block in early B cell differentiation, leading to profound hypogammaglobulinemia and few or no circulating B cells. Patients with XLA are susceptible to recurrent infections by encapsulated bacteria and enteroviruses due to antibody deficiency. Mutations in the Bruton tyrosine kinase (Btk) gene have been identified as responsible for XLA. Btk is a cytoplasmic tyrosine kinase of the Tec family important in B-lymphocyte development, differentiation, and signaling. Detection of a btk mutation allows definitive diagnosis of XLA. The aim of this study was to identify and characterize mutations in btk. Six patients were included according to the criteria of PAGID and ESID: males with less than 2% of circulating B cells, hypogammaglobulinemia and a history of recurrent bacterial infections. Mutation screening was performed with SSCP technique and possible mutations were confirmed by sequencing. Expression of Btk protein in patients and mothers was assessed in monocytes by flow cytometry. The major clinical manifestations among patients were respiratory tract infections. All had onset of symptoms during the first year of life, circulating B cells below 2% and hypogammaglobulinemia before the start of immunoglobulin replacement therapy. We identified five mutations in btk, three novel (p.Ala347fsX55, p.I355T and p.Thr324fsX24) and two recurrent mutations (p.Q196X and p.E441X). The btk mutations detection in patients enabled the screening of mothers, grandmothers and maternal aunts. Three mothers and one grandmother were confirmed XLA carriers. In addition, flow cytometric evaluation of Btk expression in monocytes revealed that Btk deficiency (4,5% a 65,2%) was present in patients and a bimodal pattern of Btk expression was observed in mothers, indicating that they were XLA carriers. In one patient no mutation was identified, but his Btk expression was reduced. The combined use of genetic analysis and flow cytometric assay of Btk protein expression allowed the definitive diagnosis of XLA and its carriers detection. / Mestrado / Saude da Criança e do Adolescente / Mestre em Saude da Criança e do Adolescente