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1.
Infection ; 37(4): 340-3, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19629385

RESUMO

BACKGROUND: Preventive measures remain the best approach to control the spread of hepatitis B virus (HBV) infection. PATIENTS AND METHODS: To evaluate the effectiveness of vaccination against HBV, we conducted a 20-year retrospective study on 100 subjects, born to hepatitis B surface antigen (HBsAg)-positive mothers, who had received postexposure prophylaxis at the Clinic of Infectious Diseases (Siena University, Italy) during 1984-2004. All patients were tested for the presence of HBsAg, anti-HBs and anti-HB core antigen (anti-HBc). RESULTS: Two subjects (2%) acquired the infection as shown by the presence of anti-HBc. Of the 98 patients who did not acquire the infection, 62 of these (63.3%) had an anti-HBs concentration considered protective (> or =10 mIU/ml). The percentage of protected subjects decreased in relation to time from vaccination with a significant reduction (p = 0.009) of anti-HBs geometric mean titre (GMT) after 5 years, which reached the level of 10 mIU/ml after about 15 years. No patients without protective concentration have acquired the infection as of today. Only 12% of the HBsAg-positive mothers were followed in specialized structures after pregnancy, reflecting the scarce knowledge of the problem in the general population. CONCLUSION: Our data, while confirming the effectiveness of anti hepatitis B vaccination, highlight the need for postvaccination follow-up, particularly in high-risk categories, to prolong protection, through booster doses if necessary. We show, moreover, the importance of maintaining active surveillance in the territory to improve follow-up to chronic carriers and to sensitize families.


Assuntos
Anticorpos Anti-Hepatite B/sangue , Antígenos de Superfície da Hepatite B/sangue , Vacinas contra Hepatite B/imunologia , Hepatite B/imunologia , Hepatite B/prevenção & controle , Complicações Infecciosas na Gravidez , Adolescente , Criança , Feminino , Humanos , Recém-Nascido , Itália , Masculino , Gravidez , Estudos Retrospectivos , Adulto Jovem
2.
Reumatismo ; 59(3): 209-14, 2007.
Artigo em Italiano | MEDLINE | ID: mdl-17898880

RESUMO

In the recent years, percutaneous vertebroplasty is available for the treatment of the vertebral fractures, primarily to relieve pain related to the lesion. In order to evaluate the efficacy and the safety of this technique, we have treated with percutaneous vertebroplasty, using polymethylmethacrylate, 22 patients, affected by one or more vertebral fractures caused by osteoporosis. All the patients satisfied the inclusion criteria of the American College of Radiology for percutaneous vertebroplasty. These patients were compared with a control group of 23 not treated subjects with vertebral fractures, using questionnaires for assessment of pain and quality of life, drug intake, use of corset, and tolerability of the surgery. In the large majority of patients, the treatment of osteoporotic vertebral fractures with percutaneous vertebroplasty resulted in a prompt, marked and sustained relief of vertebral pain with a persistent improvement of quality of life.


Assuntos
Cimentos Ósseos/uso terapêutico , Vértebras Lombares/lesões , Osteoporose/complicações , Ácidos Polimetacrílicos/uso terapêutico , Fraturas da Coluna Vertebral/terapia , Vértebras Torácicas/lesões , Idoso , Analgésicos/uso terapêutico , Dor nas Costas/tratamento farmacológico , Dor nas Costas/etiologia , Calcitriol/uso terapêutico , Cálcio/uso terapêutico , Moldes Cirúrgicos , Terapia Combinada , Difosfonatos/uso terapêutico , Feminino , Fraturas Espontâneas/diagnóstico por imagem , Fraturas Espontâneas/etiologia , Fraturas Espontâneas/terapia , Humanos , Injeções Intralesionais , Masculino , Pessoa de Meia-Idade , Osteoporose/tratamento farmacológico , Aceitação pelo Paciente de Cuidados de Saúde , Ácidos Polimetacrílicos/administração & dosagem , Radiografia Intervencionista , Estudos Retrospectivos , Fraturas da Coluna Vertebral/diagnóstico por imagem , Fraturas da Coluna Vertebral/etiologia
3.
Reumatismo ; 58(3): 230-2, 2006.
Artigo em Italiano | MEDLINE | ID: mdl-17013441

RESUMO

The treatment of bladder cancer with Bacillus of Calmette-Guerin (BCG) immunotherapy can induce the appearance of a reactive disorder. The Authors describe a 55-year-old male patient with bladder cancer treated with endovesical instillation of BCG immunotherapy, followed after the fifth application by asymmetric oligoarthritis and dactilitis. The observed positivity of both HLA-B27 and HLA-B51 antigens reinforces the hypothesis of a reactive form, possibly through "molecular mimicry" mechanism. The discontinuation of BCG instillation along which a therapeutic attempt with NSAD failed to improve the rheumatic manifestation, which completely remitted after a four-month course of oral steroids. No relapses of joint and tendon involvement was observed during the following five-month period. The clinico-pathogenetic implications suggested by this case are discussed.


Assuntos
Anti-Inflamatórios/uso terapêutico , Artrite Reativa/tratamento farmacológico , Artrite Reativa/etiologia , Vacina BCG/efeitos adversos , Carcinoma de Células de Transição/terapia , Imunoterapia Ativa/efeitos adversos , Metilprednisolona/uso terapêutico , Neoplasias da Bexiga Urinária/terapia , Administração Intravesical , Anti-Inflamatórios/administração & dosagem , Vacina BCG/administração & dosagem , Carcinoma de Células de Transição/cirurgia , Terapia Combinada , Seguimentos , Humanos , Masculino , Metilprednisolona/administração & dosagem , Pessoa de Meia-Idade , Indução de Remissão , Fatores de Tempo , Resultado do Tratamento , Neoplasias da Bexiga Urinária/cirurgia
4.
Hemoglobin ; 25(1): 35-43, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11300348

RESUMO

Prevention of beta-thalassemia implies knowledge of the molecular spectrum occurring in the population at risk. This knowledge is necessary, especially when a prevention protocol is applied to a multiethnic population. For this purpose, we have recently analyzed a large population of Iranian patients living in the Province of Hormozgan in Iran, and a small group of Iranian patients living in The Netherlands. We have found a different mutation spectrum in both populations as compared to the data obtained by other authors for the Iranian regions of Tehran, Fars, Sistan Balouchestan, Bushehr, and Khouzestan. The IVS-I-5 (G-->C) is the most frequent mutant in the province of Hormozgan (69%), followed by the IVS-II-1 (G-->A) (9.6%), while the IVS-I-1 (G-->A) was the most frequent defect found in the Iranian population sample in The Netherlands. The IVS-II-745 (C-->G) mutation in cis with the 5'UTR (untranslated region) +20 (C-->T) transition was observed in two unrelated, transfusion-dependent homozygotes, living in the Hormozgan Province where, in contrast with populations living in other provinces of Iran, no IVS-I-110 (G-->A) or IVS-I-1 (G-->A) mutations were found. We report the molecular spectra of our population samples and compare them with the mutation spectra observed in the Iranian populations by other authors. We discuss the severe phenotype of the patients homozygous for the IVS-II-745 (C-->G) mutation, linked in cis to the 5'UTR +20 (C-->T) transition. Molecular analysis using commercial kits is briefly compared with denaturing gradient gel electrophoresis, emphasizing the value of a rapid method of detection for molecular defects in areas where many mutations occur.


Assuntos
Globinas/genética , Talassemia beta/genética , Regiões 5' não Traduzidas/genética , Alelos , Substituição de Aminoácidos , Análise por Conglomerados , Análise Mutacional de DNA , Etnicidade/genética , Frequência do Gene , Triagem de Portadores Genéticos , Genótipo , Humanos , Irã (Geográfico)/epidemiologia , Irã (Geográfico)/etnologia , Mutação de Sentido Incorreto , Países Baixos/epidemiologia , Reação em Cadeia da Polimerase , Deleção de Sequência , Talassemia beta/sangue , Talassemia beta/etnologia , Talassemia beta/prevenção & controle
5.
Am J Hum Genet ; 68(4): 990-1018, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11254455

RESUMO

The genetic variance at seven Y-chromosomal microsatellite loci (or short tandem repeats [STRs]) was studied among 986 male individuals from 20 globally dispersed human populations. A total of 598 different haplotypes were observed, of which 437 (73.1%) were each found in a single male only. Population-specific haplotype-diversity values were.86-.99. Analyses of haplotype diversity and population-specific haplotypes revealed marked population-structure differences between more-isolated indigenous populations (e.g., Central African Pygmies or Greenland Inuit) and more-admixed populations (e.g., Europeans or Surinamese). Furthermore, male individuals from isolated indigenous populations shared haplotypes mainly with male individuals from their own population. By analysis of molecular variance, we found that 76.8% of the total genetic variance present among these male individuals could be attributed to genetic differences between male individuals who were members of the same population. Haplotype sharing between populations, phi(ST) statistics, and phylogenetic analysis identified close genetic affinities among European populations and among New Guinean populations. Our data illustrate that Y-chromosomal STR haplotypes are an ideal tool for the study of the genetic affinities between groups of male subjects and for detection of population structure.


Assuntos
Variação Genética/genética , Haplótipos/genética , Repetições de Microssatélites/genética , Filogenia , Cromossomo Y/genética , África , Alelos , Ásia , Europa (Continente) , Evolução Molecular , Frequência do Gene/genética , Testes Genéticos , Humanos , Masculino , Método de Monte Carlo , Nova Guiné , América do Sul
6.
Haematologica ; 86(1): 36-8, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11146568

RESUMO

BACKGROUND AND OBJECTIVES: The occurrence of Hb CS is usually limited to the geographic area which includes Southern China and South East Asia. In 1968 Hb CS was also found to occur in the Mediterranean area where it was originally described as Hb Athens. We investigated the independent origin of these termination codon mutations of the alpha 2-globin gene by determining the alpha-cluster haplotype and comparing the hematologic data from Hb CS-Hb H patients and their family members. DESIGN AND METHODS: We studied one Hb CS-Hb H patient of Greek origin and a Sicilian family in which one individual was affected by Hb CS-Hb H. The haplotype of the Hb CS allele was determined and compared to the haplotype of an Hb CS-Hb H individual of Chinese origin. RESULTS: The haplotype found for the Greek and Sicilian Hb CS was the same but differed significantly from the Asiatic Hb CS mutation. INTERPRETATION AND CONCLUSIONS: The Hb CS mutation found in both Mediterranean patients arose independently in the Mediterranean area. The difference in clinical manifestation of the Hb CS-Hb H disease in both patients is less common but consistent with similar variation in the clinical expression of analogous Hb Icaria-Hb H disease patients.


Assuntos
Hemoglobinas Anormais/genética , China , Códon de Terminação/genética , Saúde da Família , Feminino , Grécia , Haplótipos , Humanos , Masculino , Mutação Puntual , Sicília
7.
Br J Haematol ; 110(3): 694-8, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10997982

RESUMO

We describe the characterization of an alpha+-thalassaemia determinant as a result of a transition of G-->A of the donor splice consensus site sequence of the first intron of the alpha1-globin gene (alpha1IVS I-1). The mutation was found in combination with the South-East Asian alpha0-thalassaemia deletion in an haemoglobin (Hb)H patient and her sister, both of Thai origin. Sequencing of the abnormally spliced mRNA product revealed the presence of a cryptic splice site in exon 1 of the alpha1-globin gene. No normally spliced alpha1mRNA was detected. The abnormally spliced mRNA product from the alpha1-gene carrying the mutation does not lead to functional protein and causes a mild HbH-disease phenotype when in combination with the deletion type alpha0-thalassaemia.


Assuntos
Globinas/genética , Mutação Puntual , Talassemia alfa/genética , Adulto , Southern Blotting , Pré-Escolar , Eletroforese em Gel de Ágar , Feminino , Humanos , Masculino , Linhagem , Reação em Cadeia da Polimerase Via Transcriptase Reversa
9.
Clin Lab Haematol ; 21(4): 247-56, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10583326

RESUMO

The paper reports the results obtained from the study of 949 patients examined for a suspected alpha- or beta-thalassaemia using a rapid modified method of in vitro biosynthesis determination. Part of the results have been evaluated in correlation with the different molecular defects, defects combinations and with the presence of abnormal haemoglobins. The validity of the method for diagnosis of thalassaemia and particularly for the analysis of complex defects combinations which may occur in multiethnic populations is illustrated. The technology of the modified method is thoroughly described and the influence of the factors interfering with the reliability of the experiments is discussed.


Assuntos
Globinas/análise , Globinas/biossíntese , Hemoglobinopatias/diagnóstico , Hemoglobinopatias/epidemiologia , Diagnóstico Diferencial , Frequência do Gene , Testes Genéticos/economia , Testes Genéticos/métodos , Variação Genética , Globinas/genética , Doença da Hemoglobina SC/diagnóstico , Doença da Hemoglobina SC/genética , Hemoglobinas Anormais/análise , Heterozigoto , Homozigoto , Humanos , Leucina/metabolismo , Países Baixos/epidemiologia , Reticulócitos/metabolismo , Trítio , Talassemia alfa/diagnóstico , Talassemia alfa/epidemiologia , Talassemia alfa/genética , Talassemia beta/diagnóstico , Talassemia beta/epidemiologia , Talassemia beta/genética
10.
Hemoglobin ; 23(4): 317-24, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10569720

RESUMO

In this report we describe a case of Hb H disease due to the interaction of the --(MED 1) deletion with a new alpha(+)-thalassemia determinant. The molecular analysis of the proband's genomic DNA was carried out by polymerase chain reaction amplification and sequencing of both alpha genes of the alpha(+)-thalassemia chromosome and revealed a deletion of codon 62 of the alpha1 gene. This DNA triplet codes for a valine residue at the E11 alpha helix, which is located in the interior of the heme pocket. Substitutions of valine E11 with other amino acid residues in the alpha as well as beta polypeptide chains lead, in the heterozygous carrier, either to Hb M disease or to congenital non-spherocytic hemolytic anemia. We assume that the deletion of valine at alpha62(E11) disrupts the conformation of the alpha chain to such an extent that the mutated subunit is rapidly removed by proteolysis. The final result is an alpha-thalassemia phenotype rather than an unstable hemoglobin syndrome. This conclusion is supported by the apparent absence of an abnormal alpha chain in the peripheral blood of the patient.


Assuntos
Códon , Deleção de Genes , Hemoglobinas Anormais/genética , Talassemia alfa/genética , Pré-Escolar , Humanos , Masculino , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Valina
12.
Hemoglobin ; 23(2): 135-44, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10335981

RESUMO

We describe a new structural mutant of the beta-globin chain in a 17-year-old Dutch Caucasian girl. The mutant is associated with a severe pathology as a consequence of hyper-instability of the hemoglobin tetramer. The proband, whose parents had no history of hemolysis, was admitted to the hospital at 5 months of age with hemolytic anemia and splenomegaly. No indications for autoimmune defects or enzymopathies were found. Repeated hemoglobin electrophoresis on cellulose acetate revealed no abnormalities. At the age of 17 years, a minor abnormal band of less than 1% was detected on starch gel electrophoresis, migrating slightly faster than Hb A2. Sequencing of the beta-globin gene revealed heterozygosity for a 4 bp deletion (GCTA) in combination with a 1 bp insertion (T) at codons 138/139. This event eliminates two amino acids (Ala-Asn) and introduces a new residue (Tyr). We discuss the hematological and the pathophysiological consequences of this mutant, which is fully expressed as a gene product, and apparently assembled into unstable tetramers that precipitate shortly after.


Assuntos
Anemia Hemolítica/genética , Globinas/genética , Hemoglobinas Anormais/genética , Mutação , Doença Aguda , Adolescente , Anemia Hemolítica/sangue , Códon/genética , Feminino , Humanos , Países Baixos
14.
Eur J Hum Genet ; 7(2): 163-8, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10196699

RESUMO

The occurrence of point mutation alpha-thalassaemia and of complex combinations of haemoglobin defects is underestimated. Haemoglobinopathies, the most frequent monogenic recessive autosomal disorder in man, occur predominantly in Mediterranean, African and Asiatic populations. However, countries of immigration with a low incidence in the indigenous population, are now confronted with a highly heterogeneous array of imported defects. Furthermore, the occurrence of severe phenotypes is bound to increase in the near future because of the endogamous growth of the ethnical minorities and the lack of prevention. We describe an Afghan family in which both partners of a consanguineous relationship are carriers of a beta- as well as an alpha-thalassaemia determinant. The combination of defects was revealed by the in vitro measurement of the beta/alpha biosynthetic ratio and was characterised at the DNA level. The molecular defects involved are the Cd5(-CT), a Mediterranean beta zero-thalassaemia mutation, and the alpha 2(zero/+)-thalassaemia AATA(-AA) polyadenylation defect. The alpha-thalassemia defect is a rare RNA-processing mutant described only twice before in heterozygous form in Asian-Indian patients. The mutation suppresses the expression of a alpha 2 gene and reduces the expression of the less efficient, 3' located alpha 1 gene as well, inducing a near alpha zero-thalassaemia phenotype. This defect is now described for the first time in the homozygous condition in one of the children who, in addition to being homozygous for the alpha-thalassaemia point mutation, is also a carrier of the beta zero-thalassaemia defect. A previously described homozygous case of the alpha (zero/+)-thalassaemia condition, caused by a similar polyadenylation defect, was characterised by a severe HbH disease. However, the patient described here present at 7 years of age with severe caries, like his beta-thalassaemia homozygous brother but without hepatosplenomegaly, haemolysis or severe anaemia. The haematological analysis revealed 9.5 g/dl Hb; 5.4 x 10(12)/I RBC; 0.33 I/I PCV; 61 fl MCV; 17.6 pg MCH and 6.2% of HbA2. The biosynthetic ratio beta:alpha was 1.6 and no HbH fraction was detectable either on electrophoresis or as inclusion bodies. The parents reported no complications during pregnancy, at birth, or in the neonatal period in rural Afghanistan. We presume therefore that the counterbalancing effect induced by the co-existing beta-thalassaemia defect could have modified a potentially severe perinatal HbH disease into a strongly hypochromic but well compensated 'alpha zero-like heterozygous' thalassaemia phenotype. The risk of a severe HbH disease, could have been easily missed in this family which was referred because of a child affected with beta-thalassaemia major.


Assuntos
Talassemia alfa/genética , Talassemia beta/genética , Feminino , Hematologia , Humanos , Masculino , Linhagem
15.
Prenat Diagn ; 18(11): 1131-7, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9854720

RESUMO

We have developed a two-colour immunocytochemical staining method for the detection of fetal and embryonic haemoglobin in erythroid cells. The method was applied to study these haemoglobin types in fetal red cells. Specimens from fetal blood (10 weeks), cord blood and fetal liver (14 weeks) as well as chorionic villus samples (10-13 weeks) were stained for gamma and epsilon chains using CY3 and FITC labelled antibodies. Morphometric analysis was applied to determine cell size. Samples from organs involved in early embryonic development contained relatively large erythroblasts expressing the epsilon globin chain (megaloblasts); later in gestation the gamma chain was co-expressed by the same cells which ultimately became smaller and contained HbF (alpha 2 gamma 2) only. This phenomenon was confirmed in CVS samples in which all cell types were abundantly present. Since fetal erythroblasts are considered candidate cells for non-invasive prenatal diagnosis using FISH, we studied the phenotype of erythroblasts circulating in the maternal blood. The majority of erythroblasts in maternal blood appeared to be of the relatively small gamma globin-containing cell type. However, careful screening of the same maternal blood samples also revealed erythroblasts expressing epsilon or epsilon and gamma globins simultaneously, although at low frequency. Control specimens from non-pregnant women did not show nucleated red cells expressing either of the haemoglobin types. These observations may contribute to the better recognition of fetal cells in the maternal blood for prenatal diagnosis.


Assuntos
Eritrócitos/química , Sangue Fetal/citologia , Globinas/análise , Imuno-Histoquímica/métodos , Coloração e Rotulagem , Amostra da Vilosidade Coriônica , Eritroblastos/química , Feminino , Idade Gestacional , Humanos , Hibridização in Situ Fluorescente , Fígado/citologia , Fígado/embriologia , Gravidez
16.
Br J Haematol ; 103(2): 370-6, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9827907

RESUMO

We describe a family with beta thalassaemia, apparently not linked to the beta-globin gene cluster, in combination with alpha thalassaemia. The propositus, an adult Dutch Caucasian male, and his son presented with microcytic hypochromic parameters. Their lysates displayed the normal adult pattern on electrophoresis. The HbA2 concentration, which is usually increased in beta thalassaemia, was normal. The in vitro biosynthetic rate of the globin chains was strongly unbalanced even in the presence of a coexisting alpha-thalassaemia defect. Routine analysis of the beta genes, including the promoter region, was performed repeatedly by polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGCE) and direct sequencing. No molecular abnormalities were detected. Large beta deletions were excluded by haplotype determination, using seven polymorphic markers distributed over an area of 50 kb, from 1 kb 5' of the epsilon gene to 4 kb 3' of the beta gene. The haplotype analysis of the beta-gene cluster revealed that the unaffected daughter had received the same beta haplotype as her beta-thalassaemic brother from their beta-thalassaemic father. These data suggest that the beta-gene cluster shared by father and son was not directly associated with a reduced beta-globin chain expression. In order to exclude the remote possibility of a beta-locus-control region (LCR) rearrangement in the paternal haplotype of the daughter, the sequence of the HS2 element was examined in the nuclear family. We compared the haematological and clinical data of this family with the data reported in the limited number of similar cases. We discuss the possibility that the mutation of a trans-acting erythroid factor(s), not linked to the beta-genes cluster, may impair the beta-gene expression of both alleles.


Assuntos
Deleção de Genes , Globinas/genética , Mutação Puntual , Talassemia alfa/genética , Talassemia beta/genética , Adolescente , Feminino , Haplótipos , Humanos , Região de Controle de Locus Gênico , Masculino , Pessoa de Meia-Idade , Linhagem , Reação em Cadeia da Polimerase Via Transcriptase Reversa
17.
Cytometry ; 32(3): 170-7, 1998 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-9667505

RESUMO

In order to detect fetal nucleated red blood cells (NRBCs) in maternal blood, a protocol was developed which aimed at producing a reliable staining method for combined immunocytochemical and FISH analysis. The technique had to be suitable for eventual automated screening of slides. Chorionic villi washings, cord blood, and maternal blood samples were used for this study. After a density gradient separation and centrifugal cytology, slides were stained either with 3,3-diaminobenzidin (DAB), a marker for heme, or with antibodies against the gamma-chain of fetal hemoglobin (HbF). FISH analysis for both X- and Y-chromosomes was performed on the same slides. Cytocentrifugation provided a controlled cell density on the slides with good cell morphology. Both the DAB and HbF staining were suitable for manual screening of large numbers of slides. The HbF staining, although supposed to be more specific for fetal NRBCs, appeared to be more sensitive to minor changes in preparation. We were eventually able to combine HbF staining with FISH analysis, and produced a detection efficiency of >85% for both X- and Y-chromosome signals. This preparation protocol simplifies the detection of NRBCs in maternal blood. Immunocytochemical staining and FISH analysis can be performed on the same cell with good image contrast, thus facilitating both manual and automated image analysis. This will facilitate the use of this approach for prenatal diagnosis.


Assuntos
Eritroblastos/química , Feto/química , Feto/citologia , Hibridização in Situ Fluorescente , 3,3'-Diaminobenzidina , Centrifugação com Gradiente de Concentração , Contagem de Eritrócitos , Feminino , Ficoll , Humanos , Imuno-Histoquímica , Masculino , Gravidez , Coloração e Rotulagem , Fixação de Tecidos
18.
Ann Hematol ; 77(6): 249-55, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9875660

RESUMO

Eight patients who were carriers of beta-thalassemia induced by the cd121 (G-->T) mutation are described in four nonrelated Dutch families. This mutant, which is considered rare and inherited in a dominant manner, is expressed in a different way among each of the four families and even among carriers of the same family. The symptoms vary from an hemolytic anemia of intermediate gravity with hepatosplenomegaly, inclusion bodies and erythroblastosis, to a mild anemia with minor hematological abnormalities. We report the analytical procedures used for the detection of the mutant, the hematological and clinical data of the four families and discuss the variable physiopathology of this molecular defect. We also compare the variation in fetal hemoglobin expression in relation to the haplotypes of the beta-gene cluster and to the different hematological conditions. The presence of this rare mutant in four nonrelated Dutch families could derive from a single mutation or from multiple events. The existence of the four mutations in three different haplotypes suggests the occurrence of at least two independent events. The presence of five abnormal hemoglobins and the beta-thalassemia defect on different haplotypes at cd121 also suggests a relatively increased rate of mutations at this particular site.


Assuntos
Talassemia beta/epidemiologia , Talassemia beta/genética , Adulto , Feminino , Amplificação de Genes , Genes Dominantes , Globinas/genética , Guanosina/genética , Humanos , Masculino , Pessoa de Meia-Idade , Países Baixos/epidemiologia , Linhagem , Fenótipo , Mutação Puntual , Timidina/genética , Talassemia beta/sangue
19.
Baillieres Clin Haematol ; 11(1): 53-90, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10872473

RESUMO

alpha-Thalassaemias are genetic defects extremely frequent in some populations and are characterized by the decrease or complete suppression of alpha-globin polypeptide chains. The gene cluster, which codes for and controls the production of these polypeptides, maps near the telomere of the short arm of chromosome 16, within a G + C rich and early-replicating DNA region. The genes expressed during the embryonic (zeta) or fetal and adult stage (alpha 2 and alpha 1) can be modified by point mutations which affect either the processing-translation of mRNA or make the polypeptide chains extremely unstable. Much more frequent are the deletions of variable size (from approximately 3 to more than 100 kb) which remove one or both alpha genes in cis or even the whole gene cluster. Deletions of a single gene are the result of unequal pairing during meiosis, followed by reciprocal recombination. These unequal cross-overs, which produce also alpha gene triplications and quadruplications, are made possible by the high degree of homology of the two alpha genes and of their flanking sequences. Other deletions involving one or more genes are due to recombinations which have taken place within non-homologous regions (illegitimate recombinations) or in DNA segments whose homology is limited to very short sequences. Particularly interesting are the deletions which eliminate large DNA areas 5' of zeta or of both alpha genes. These deletions do not include the structural genes but, nevertheless, suppress completely their expression. Larger deletions involving the tip of the short arm of chromosome 16 by truncation, interstitial deletions or translocations result in the contiguous gene syndrome ATR-16. In this complex syndrome alpha-thalassaemia is accompanied by mental retardation and variable dismorphic features. The study of mutations of the 5' upstream flanking region has led to the discovery of a DNA sequence, localized 40 kb upstream of the zeta-globin gene, which controls the expression of the alpha genes (alpha major regulatory element or HS-40). In the acquired variant of haemoglobin H (HbH) disease found in rare individuals with myelodysplastic disorders and in the X-linked mental retardation associated with alpha-thalassaemia, a profound reduction or absence of alpha gene expression has been observed, which is not accompanied by structural alterations of the coding or controlling regions of the alpha gene complex. Most probably the acquired alpha-thalassaemia is due to the lack of soluble activators (or presence of repressors) which act in trans and affect the expression of the homologous clusters and are coded by genes not (closely) linked to the alpha genes. The ATR-X syndrome results from mutations of the XH2 gene, located on the X chromosome (Xq13.3) and coding for a transacting factor which regulates gene expression. The interaction of the different alpha-thalassaemia determinants results in three phenotypes: the alpha-thalassaemic trait, clinically silent and presenting only limited alterations of haematological parameters, HbH disease, characterized by the development of a haemolytic anaemia of variable degree, and the (lethal) Hb Bart's hydrops fetalis syndrome. The diagnosis of alpha-thalassaemia due to deletions is implemented by the electrophoretic analysis of genomic DNA digested with restriction enzymes and hybridized with specific molecular probes. Recently polymerase chain reaction (PCR) based strategies have replaced the Southern blotting methodology. The straightforward identification of point mutations is carried out by the specific amplification of the alpha 2 or alpha 1 gene by PCR followed by the localization and identification of the mutation with a variety of screening systems (denaturing gradient gel electrophoresis (DGGE), single strand conformation polymorphisms (SSCP)) and direct sequencing.


Assuntos
Talassemia alfa , Animais , Sequência de Bases , Deleção de Genes , Expressão Gênica , Globinas/genética , Humanos , Camundongos , Dados de Sequência Molecular , Mutação , Mutação Puntual , Talassemia alfa/sangue , Talassemia alfa/epidemiologia , Talassemia alfa/genética
20.
Community Genet ; 1(4): 243-51, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-15178968

RESUMO

The prevalence at birth of hemoglobin defects in the autochthonous North-European population is low. However, the long immigration and colonial history of the Netherlands has resulted in a group of about 1-2 million 'autochthonous' inhabitants, with Asian, South-European or African ancestors, in whom a moderate birth prevalence of globin gene mutations can be expected. Furthermore, at least 10% of the Dutch population consists of recent immigrants from different countries with high birth prevalence of hemoglobinopathies. Because of the endogamous partner choice, which is prevalent in this population, the risk for homozygous progeny remains elevated. At least 100,000 carriers of hemoglobinopathies of recent allochthonous origin are present in the Netherlands, and the number of homozygous children is rising. Prevention by prenatal diagnosis requires a suitable protocol and knowledge about the molecular defects present in the country. Therefore we have analyzed a large number of patients and carriers, both at the hematological and at the DNA level. Our survey revealed 47 different beta-thalassemia determinants, characterized on 223 independent chromosomes from individuals of different ethnic origins. As expected, the most prevalent mutations were largely represented. The cd39 (C-->T) mutation was found in 70% of the immigrants from Morocco, Sardinia and other Central-West-Mediterranean regions while the IVS-I-110 (G-->A) was prevalent in the East-Mediterranean populations. The IVS-I-5 (G-->C) mutation was found in 45% of the patients of Indonesian origin. We also registered 308 independent chromosomes with common structural defects (HbS, HbC, HbE, Hb Lepore, Hb Constant Spring and HbD Punjab) and 33 chromosomes with 19 different, less frequent, rare or very rare mutants. Seven structural mutants were described for the first time and published separately. Furthermore, 139 independent chromosomes with deletional and nondeletional alpha-thalassemia defects were characterized.

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