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1.
Blood ; 136(24): 2803-2811, 2020 12 10.
Artículo en Inglés | MEDLINE | ID: mdl-32603413

RESUMEN

Cure rates for primary mediastinal large B-cell lymphoma (PMBCL) have improved with the integration of rituximab. However, the type of primary therapy and role of radiotherapy (RT) remains ill-defined. Herein, we evaluated the outcome of PMBCL primarily treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and the impact of an end-of-treatment (EOT) 18F-fluorodeoxyglucose positron emission tomography (PET) scan to guide consolidative RT. Patients ≥18 years of age with PMBCL treated with curative intent rituximab-chemotherapy were identified. Prior to 2005, patients were recommended to receive R-CHOP + RT (RT era). Beginning in 2005, EOT PET was used to guide RT and only those with a PET-positive scan received RT (PET era). In total, 159 patients were identified, 94% were treated with R-CHOP and 44% received RT (78% in RT era, 28% in PET era). The 5-year time to progression (TTP) and overall survival (OS) for the entire cohort were 80% and 89%, respectively, similar across treatment eras. Overall, 10% had refractory disease. In total, 113 patients had an EOT PET scan: 63% negative and 37% positive with a 5-year TTP of 90% vs 71% and 5-year OS of 97% vs 88%, respectively. For those with Deauville (D)-scored PET scans (n = 103), the 5-year TTP for PET-negative cases by Deauville criteria (D1-D3, DX) was 91%, with inferior outcomes for D5 vs D4 (5-year TTP 33% vs 87%, P = .0002). Outcomes for PMBCL treated with RCHOP are favorable and use of a PET-adapted approach reduces RT in the majority of patients. A small proportion have refractory disease and may benefit from an alternate treatment.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Linfoma de Células B Grandes Difuso , Neoplasias del Mediastino , Tomografía de Emisión de Positrones , Adulto , Anciano , Anciano de 80 o más Años , Ciclofosfamida/administración & dosificación , Supervivencia sin Enfermedad , Doxorrubicina/administración & dosificación , Femenino , Estudios de Seguimiento , Humanos , Linfoma de Células B Grandes Difuso/diagnóstico por imagen , Linfoma de Células B Grandes Difuso/tratamiento farmacológico , Linfoma de Células B Grandes Difuso/mortalidad , Masculino , Neoplasias del Mediastino/diagnóstico por imagen , Neoplasias del Mediastino/tratamiento farmacológico , Neoplasias del Mediastino/mortalidad , Persona de Mediana Edad , Prednisona/administración & dosificación , Rituximab/administración & dosificación , Tasa de Supervivencia , Vincristina/administración & dosificación
2.
Br J Haematol ; 189(1): 122-127, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31822034

RESUMEN

A novel prognostic score (IPS-3), comprised of only three of the seven IPS-7 indicators (age ≥45, stage IV, haemoglobin <105 g/l), was recently proposed as a simplified model for advanced-stage classic Hodgkin lymphoma (cHL). We aimed to validate this model in advanced-stage cHL patients treated with doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) in British Columbia. The estimated five-year freedom from progression (FFP) for scores of 0, 1, 2 and 3 were very similar to the original report at 84%, 76%, 72% and 68% respectively. The IPS-3 score is highly reproducible in this independent dataset and its simplicity makes it appealing for everyday clinical practice.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Enfermedad de Hodgkin/tratamiento farmacológico , Enfermedad de Hodgkin/mortalidad , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Bleomicina/administración & dosificación , Colombia Británica/epidemiología , Dacarbazina/administración & dosificación , Supervivencia sin Enfermedad , Doxorrubicina/administración & dosificación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Tasa de Supervivencia , Vinblastina/administración & dosificación
3.
Ann Hematol ; 96(8): 1241-1251, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28497365

RESUMEN

The serum-soluble interleukin-2 receptor (sIL-2r) level is considered an important diagnostic test and disease marker in hemophagocytic syndromes/hemophagocytic lymphohistiocytosis (HPS/HLH). However, this cytokine receptor is rarely measured in clinical practice and has been excluded from recent diagnostic/classification criteria such as the HScore and macrophage activation syndrome (MAS) 16. We performed a systematic scoping review of 64 articles (1975-2016) examining the clinical utility of sIL-2r in HPS/HLH. Twenty-two articles describe sIL-2r as a sensitive diagnostic marker for HLH, but only three distinct datasets actually address sensitivity. The original HLH-2004 Guidelines reported sensitivity of 93% and specificity of 100% for sIL-2r ≥ 2400, based on a pediatric dataset (n = 152) which is published for the first time in this review. Two pediatric studies reported sensitivity of 89% for sIL-2r ≥ 2400 in diagnosis of MAS complicating juvenile idiopathic arthritis (JIA) (n = 27) and 88% for secondary HLH in acute liver failure (n = 9). Twenty articles described sIL-2r as a dynamic marker of disease activity that falls with response to treatment, and 15 described high initial sIL-2r levels >10,000 U/mL as a poor prognostic marker. The ability of sIL-2r to distinguish between subtypes of HPS/HLH was inconsistent. This review confirms the importance of soluble IL-2r as a diagnostic and disease marker in HPS/HLH, but also reveals the need for more primary data about its performance characteristics, particularly in adults. More emphasis should be made in including this simple, inexpensive test in clinical practice and studies of HPS/HLH.


Asunto(s)
Biomarcadores/sangre , Linfohistiocitosis Hemofagocítica/sangre , Linfohistiocitosis Hemofagocítica/diagnóstico , Receptores de Interleucina-2/sangre , Niño , Preescolar , Humanos , Linfohistiocitosis Hemofagocítica/terapia , Síndrome de Activación Macrofágica/sangre , Síndrome de Activación Macrofágica/diagnóstico , Pronóstico , Sensibilidad y Especificidad , Solubilidad
5.
BMC Public Health ; 14: 1153, 2014 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-25377274

RESUMEN

BACKGROUND: Illicit drug use is a well-established risk factor for morbidity and mortality. However, few studies have examined the impact of different drug use patterns on mortality among polysubstance using populations. This study aimed to identify drug-specific patterns of mortality among a cohort of polysubstance using persons who inject drugs (PWIDs). METHODS: PWIDs in Vancouver, Canada were prospectively followed between May 1996 and December 2011. Participants were linked to the provincial vital statistics database to ascertain mortality rates and causes of death. We used multivariate Cox proportional hazards regression to investigate the relationships between drug use patterns (daily alcohol use, heroin injection and non-injection use, cocaine injection, amphetamine injection and non-injection use, crack smoking and speedball injecting) and time to all-cause mortality. RESULTS: 2330 individuals were followed for a median of 61 months (inter-quartile range: 33 - 112). In total, 466 (19.1%) individuals died for an incidence density of 3.1 (95% confidence interval [CI]: 2.8 - 3.4) deaths per 100 person-years. In multivariate analyses, after adjusting for HIV infection and other potential confounders, only daily cocaine injection remained independently associated with all-cause mortality (adjusted hazard ratio [AHR] = 1.36, 95% CI: 1.06 - 1.76). CONCLUSIONS: Although heroin injecting is traditionally viewed as carrying the highest risk of mortality, in this setting, only daily cocaine injecting was associated with all-cause mortality. These findings highlight the urgent need to identify novel treatments and harm reduction strategies for cocaine injectors.


Asunto(s)
Trastornos Relacionados con Cocaína/epidemiología , Asunción de Riesgos , Abuso de Sustancias por Vía Intravenosa/epidemiología , Adulto , Colombia Británica/epidemiología , Trastornos Relacionados con Cocaína/etiología , Trastornos Relacionados con Cocaína/prevención & control , Estudios de Cohortes , Femenino , Infecciones por VIH/complicaciones , Humanos , Incidencia , Masculino , Grupos de Población , Estudios Prospectivos , Factores de Riesgo , Abuso de Sustancias por Vía Intravenosa/etiología , Abuso de Sustancias por Vía Intravenosa/prevención & control
6.
Case Rep Surg ; 2024: 2061453, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38716134

RESUMEN

Internal hernias are difficult to diagnose clinically, and normal cross-sectional imaging has been documented in many patients. Transmesenteric hernias from congenital defects or prior abdominal surgery are most common. A 46-year-old previously healthy female presented to the emergency department with acute onset nausea and vomiting eight years after a right ureteral transection during a laparoscopic hysterectomy, with a delayed ureterolysis and reimplantation into the bladder. Rectal contrast CT scan demonstrated a partial large bowel obstruction that was unclear if it was due to an underlying mass, stricture, or internal herniation. The patient was taken for exploratory laparotomy which demonstrated redundant transverse colon herniated under the mobile right ureter; an extended right hemicolectomy was performed. This report describes alteration of retroperitoneal anatomy creating a potential space for colonic herniation and emphasizes that clinical suspicion must remain high for patients presenting with obstructive or partially obstructive symptoms.

7.
Cancers (Basel) ; 16(6)2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-38539425

RESUMEN

OBJECTIVES: Accurate outcome prediction is important for making informed clinical decisions in cancer treatment. In this study, we assessed the feasibility of using changes in radiomic features over time (Delta radiomics: absolute and relative) following chemotherapy, to predict relapse/progression and time to progression (TTP) of primary mediastinal large B-cell lymphoma (PMBCL) patients. MATERIAL AND METHODS: Given the lack of standard staging PET scans until 2011, only 31 out of 103 PMBCL patients in our retrospective study had both pre-treatment and end-of-treatment (EoT) scans. Consequently, our radiomics analysis focused on these 31 patients who underwent [18F]FDG PET-CT scans before and after R-CHOP chemotherapy. Expert manual lesion segmentation was conducted on their scans for delta radiomics analysis, along with an additional 19 EoT scans, totaling 50 segmented scans for single time point analysis. Radiomics features (on PET and CT), along with maximum and mean standardized uptake values (SUVmax and SUVmean), total metabolic tumor volume (TMTV), tumor dissemination (Dmax), total lesion glycolysis (TLG), and the area under the curve of cumulative standardized uptake value-volume histogram (AUC-CSH) were calculated. We additionally applied longitudinal analysis using radial mean intensity (RIM) changes. For prediction of relapse/progression, we utilized the individual coefficient approximation for risk estimation (ICARE) and machine learning (ML) techniques (K-Nearest Neighbor (KNN), Linear Discriminant Analysis (LDA), and Random Forest (RF)) including sequential feature selection (SFS) following correlation analysis for feature selection. For TTP, ICARE and CoxNet approaches were utilized. In all models, we used nested cross-validation (CV) (with 10 outer folds and 5 repetitions, along with 5 inner folds and 20 repetitions) after balancing the dataset using Synthetic Minority Oversampling TEchnique (SMOTE). RESULTS: To predict relapse/progression using Delta radiomics between the baseline (staging) and EoT scans, the best performances in terms of accuracy and F1 score (F1 score is the harmonic mean of precision and recall, where precision is the ratio of true positives to the sum of true positives and false positives, and recall is the ratio of true positives to the sum of true positives and false negatives) were achieved with ICARE (accuracy = 0.81 ± 0.15, F1 = 0.77 ± 0.18), RF (accuracy = 0.89 ± 0.04, F1 = 0.87 ± 0.04), and LDA (accuracy = 0.89 ± 0.03, F1 = 0.89 ± 0.03), that are higher compared to the predictive power achieved by using only EoT radiomics features. For the second category of our analysis, TTP prediction, the best performer was CoxNet (LASSO feature selection) with c-index = 0.67 ± 0.06 when using baseline + Delta features (inclusion of both baseline and Delta features). The TTP results via Delta radiomics were comparable to the use of radiomics features extracted from EoT scans for TTP analysis (c-index = 0.68 ± 0.09) using CoxNet (with SFS). The performance of Deauville Score (DS) for TTP was c-index = 0.66 ± 0.09 for n = 50 and 0.67 ± 03 for n = 31 cases when using EoT scans with no significant differences compared to the radiomics signature from either EoT scans or baseline + Delta features (p-value> 0.05). CONCLUSION: This work demonstrates the potential of Delta radiomics and the importance of using EoT scans to predict progression and TTP from PMBCL [18F]FDG PET-CT scans.

8.
Am J Surg ; 226(6): 896-900, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37633763

RESUMEN

INTRODUCTION: Nearly 20% of ventral hernia repair (VHR) patients require a subsequent abdominal operation (SAO), and mesh position may impact the complexity and outcome of the SAO. METHODS: Retrospective review of VHR with mesh from 2006 to 2020 from an internal database and the ACHQC. Primary outcomes measured incidence, complexity, and complications of SAO relative to mesh position. RESULTS: SAO was required in 433 of 2539 (17.1%) patients, totaling 671 operations; 197/893 (22.1%) with intraperitoneal mesh (IPM) and 236/1646 (14.3%) with extraperitoneal mesh (EPM; p â€‹< â€‹0.001). SAO was directly related to VHR in 180 (232 total SAOs) and unrelated in 253 (439 total SAOs). There were no significant differences in complications after SAO between IPM and EPM, nor any difference in adhesion complexity. CONCLUSION: Incidence of SAO is higher with IPM, but surgical outcomes are similar. Due to the risk of secondary mesh infection with IPM, significantly more of these were removed at the time of SAO.


Asunto(s)
Hernia Ventral , Mallas Quirúrgicas , Humanos , Hernia Ventral/cirugía , Herniorrafia , Adherencias Tisulares/cirugía , Incidencia , Estudios Retrospectivos , Recurrencia , Resultado del Tratamiento
9.
Am J Hum Genet ; 84(3): 351-66, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19249009

RESUMEN

Huntington disease (HD) is an autosomal-dominant disorder that results from >or=36 CAG repeats in the HD gene (HTT). Approximately 10% of patients inherit a chromosome that underwent CAG expansion from an unaffected parent with <36 CAG repeats. This study is a comprehensive analysis of genetic diversity in HTT and reveals that HD patients of European origin (n = 65) have a significant enrichment (95%) of a specific set of 22 tagging single nucleotide polymorphisms (SNPs) that constitute a single haplogroup. The disease association of many SNPs is much stronger than any previously reported polymorphism and was confirmed in a replication cohort (n = 203). Importantly, the same haplogroup is also significantly enriched (83%) in individuals with 27-35 CAG repeats (intermediate alleles, n = 66), who are unaffected by the disease, but have increased CAG tract sizes relative to the general population (n = 116). These data support a stepwise model for CAG expansion into the affected range (>or=36 CAG) and identifies specific haplogroup variants in the general population associated with this instability. The specific variants at risk for CAG expansion are not present in the general population in China, Japan, and Nigeria where the prevalence of HD is much lower. The current data argue that cis-elements have a major predisposing influence on CAG instability in HTT. The strong association between specific SNP alleles and CAG expansion also provides an opportunity of personalized therapeutics in HD where the clinical development of only a small number of allele-specific targets may be sufficient to treat up to 88% of the HD patient population.


Asunto(s)
Susceptibilidad a Enfermedades , Proteínas del Tejido Nervioso/genética , Proteínas Nucleares/genética , Polimorfismo de Nucleótido Simple , Repeticiones de Trinucleótidos , Pueblo Asiatico , Población Negra , Bases de Datos Genéticas , Femenino , Humanos , Proteína Huntingtina , Enfermedad de Huntington/genética , Masculino , Población Blanca
10.
Jt Comm J Qual Patient Saf ; 36(7): 310-8, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21226384

RESUMEN

BACKGROUND: Service recovery refers to an organizations entire process for facilitating resolution of dissatisfactions, whether or not visible to patients and families. Patients are an important resource for reporting miscommunications, provider inattention, rudeness, or delays, especially if they perceive a connection to misdiagnosis or failed treatment. Health systems that encourage patients to be "the eyes and ears" of individual and team performance capitalize on a rich source of data for quality improvement and risk prevention. Effective service recovery requires organizations (1) to learn about negative perceptions and experiences and (2) to create an infrastructure that supports staff's ability to respond. Service recovery requires the exercise of both basic and advanced skills. We term certain skills as advanced because of the significant variation in their use or endorsement among 30 health care organizations in the United States. BEST PRACTICES FOR BASIC SERVICE RECOVERY: On the basis of our work with the 30 organizations, a mnemonic, HEARD, incorporates best practices for basic service recovery processes: Hearing the person's concern; Empathizing with the person raising the issue; Acknowledging, expressing appreciation to the person for sharing, and Apologizing when warranted; Responding to the problem, setting time lines and expectations for follow-up; and Documenting or Delegating the documentation to the appropriate person. BEST PRACTICES FOR ADVANCED SERVICE RECOVERY: Impartiality, chain of command, setting boundaries, and Documentation represent four advanced service recovery skills critical for addressing challenging situations. CONCLUSION: Using best practices in service recovery enables the organization to do its best to make right what patients and family members experience as wrong.


Asunto(s)
Relaciones Paciente-Hospital , Readmisión del Paciente , Satisfacción del Paciente , Mejoramiento de la Calidad/organización & administración , Humanos , Estudios de Casos Organizacionales
11.
EJHaem ; 1(1): 277-280, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35847699

RESUMEN

Etoposide-based treatment is the standard of care for adult HLH in many centers, yet there remains a paucity of data regarding treatment outcomes. We conducted a retrospective study of 23 adults treated with etoposide-based therapy compared to 10 pediatric HLH cases at a single center. At diagnosis, the median serum ferritin was 20,071 µg/L and 937 µg/L in adults and children, respectively; median sIL-2r was 14,524 U/mL and 4,478 U/mL. Biochemical response to treatment was high, with 21/23 adults achieving >75% reduction in serum ferritin, but one year survival was only 7/21 compared to 7/10 in pediatric cases.

12.
Circulation ; 114(12): 1301-9, 2006 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-16940190

RESUMEN

BACKGROUND: Extrahepatic tissues have long been considered critical contributors of cholesterol to nascent HDL particles in the reverse cholesterol transport pathway, in which ABCA1 plays the crucial role. Recent studies, however, including both overexpression and deletion of ABCA1 selectively in the liver, have highlighted the primary role of the liver in the maintenance of HDL levels in vivo. METHODS AND RESULTS: The availability of mice with complete deletion of ABCA1 (total knockout [TKO]) and with liver-specific deletion of ABCA1 (LSKO) has enabled us to dissect the discrete roles of hepatic relative to extrahepatic ABCA1 in HDL biogenesis. Delivery of adenoviral ABCA1 resulted in selective expression of physiological levels of ABCA1 in the livers of both LSKO and TKO mice, resulting in increased HDL cholesterol (HDL-C). Expression of ABCA1 in the liver of LSKO mice resulted in plasma HDL-C levels that were similar to those in wild-type mice and significantly above those seen in similarly treated TKO mice. HDL particles from ABCA1-expressing LSKO mice were larger and contained significantly increased cholesterol compared with TKO mice. Infusion of human apolipoprotein A-I/phospholipid reconstituted HDL particles normalized plasma HDL-C levels in LSKO mice but had no effect on HDL-C levels in TKO mice. CONCLUSIONS: Although hepatic ABCA1 appears crucial for phospholipid transport, extrahepatic tissues play an important role in cholesterol transfer to nascent HDL particles. These data highlight the discrete and specific roles of both liver and extrahepatic ABCA1 in HDL biogenesis in vivo and indicate that ABCA1 shows lipid cargo selectivity depending on its site of expression.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/fisiología , HDL-Colesterol/sangre , Hígado/metabolismo , Transportador 1 de Casete de Unión a ATP , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Adenoviridae , Animales , Apolipoproteína A-I/farmacología , HDL-Colesterol/genética , Femenino , Regulación de la Expresión Génica , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados
13.
Blood Adv ; 1(26): 2529-2534, 2017 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-29296904

RESUMEN

Serum soluble interleukin-2 receptor (sIL-2r) is an important disease marker in hemophagocytic lymphohistiocytosis (HLH), but there are no published data on its diagnostic value in adults. We conducted a single-center retrospective study of 78 consecutive adults who had sIL-2r measured for suspected HLH. Serum sIL-2r levels were measured by enzyme-linked immunosorbent assay (adult reference range, 241-846 U/mL). There were 38 patients with HLH and 40 with a non-HLH diagnosis (such as sepsis, liver disease, histiocyte disorders, autoimmune disease, leukemia, or lymphoma). The receiver operating characteristic curve demonstrated that sIL-2r is a good to excellent diagnostic test for adult HLH, with an area under the curve (AUC) of 0.90 (95% confidence interval, 0.83-0.97) compared with AUC 0.78 (95% confidence interval, 0.67-0.88) for ferritin. The optimal threshold for sIL-2r was 2515 U/mL (sensitivity, 100%; specificity, 72.5%). Although there was a large indeterminate range for sIL-2r, a level of 2400 U/mL or less was helpful for ruling out HLH (sensitivity, 100%), and more than 10 000 U/mL was helpful for ruling in HLH (specificity, 93%). Higher mean sIL-2r levels were seen in malignancy-associated HLH (20 241 U/mL) compared with infection-associated HLH and macrophage activation syndrome (9720 and 5008 U/mL, respectively; P < .05). Levels above 10 000 U/mL were not associated with worse prognosis in patients with HLH. Serum sIL-2r is a sensitive test for diagnosis of adult HLH, but is not as specific as previously reported in children. Additional studies enriched with patients without HLH who have conditions associated with T-cell activation, such as lymphoma and autoimmune lymphoproliferative syndrome, are needed.

15.
Blood Rev ; 30(6): 411-420, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27238576

RESUMEN

Most knowledge of hemophagocytic syndromes (HPSs) including hemophagocytic lymphohistiocytosis (HLH) is derived from pediatric studies; literature on adult HPS/HLH predominantly consists of small retrospective studies with clinical and methodological heterogeneity. The aims of this systematic scoping review were to provide an overview of existing literature on adult HPS/HLH, describe current practices in diagnosis and treatment, and propose priorities for future research. Articles from Ovid Medline, Embase and Pubmed (1975-2015) describing 10 or more unique adults (age>15years) with HPS/HLH were included. 82 publications were eligible: 10 were prospective and 72 were retrospective. Of the six distinct diagnostic criteria, the HLH-2004 criteria were by far the most commonly used. A minority of studies tested for genetic abnormalities (12), soluble interleukin-2 receptor (11), and/or NK function (11) in a subset of patients. Most centers used steroids and either etoposide-based (HLH-94/HLH-2004) or doxorubicin-based (CHOP) initial therapy regimens. Allogeneic hematopoietic cell therapy for treatment of adult HLH has rarely been reported. Mortality in larger treatment focused studies ranged from 20 to 88%. Developing adult-specific diagnostic criteria based on widely evaluable features of secondary HPS/HLH and establishing standard initial therapies are priorities for future research.


Asunto(s)
Linfohistiocitosis Hemofagocítica/diagnóstico , Linfohistiocitosis Hemofagocítica/terapia , Terapia Combinada , Susceptibilidad a Enfermedades , Humanos , Linfohistiocitosis Hemofagocítica/epidemiología , Linfohistiocitosis Hemofagocítica/etiología , Guías de Práctica Clínica como Asunto , Pronóstico , Resultado del Tratamiento
16.
Eur J Hum Genet ; 19(5): 561-6, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21248742

RESUMEN

Huntington disease (HD) results from CAG expansion in the huntingtin (HTT) gene. Although HD occurs worldwide, there are large geographic differences in its prevalence. The prevalence in populations derived from Europe is 10-100 times greater than in East Asia. The European general population chromosomes can be grouped into three major haplogroups (group of similar haplotypes): A, B and C. The majority of HD chromosomes in Europe are found on haplogroup A. However, in the East-Asian populations of China and Japan, we find the majority of HD chromosomes are associated with haplogroup C. The highest risk HD haplotypes (A1 and A2), are absent from the general and HD populations of China and Japan, and therefore provide an explanation for why HD prevalence is low in East Asia. Interestingly, both East-Asian and European populations share a similar low level of HD on haplogroup C. Our data are consistent with the hypothesis that different HTT haplotypes have different mutation rates, and geographic differences in HTT haplotypes explain the difference in HD prevalence. Further, the bias for expansion on haplogroup C in the East-Asian population cannot be explained by a higher average CAG size, as haplogroup C has a lower average CAG size in the general East-Asian population compared with other haplogroups. This finding suggests that CAG-tract size is not the only factor important for CAG instability. Instead, the expansion bias may be because of genetic cis-elements within the haplotype that influence CAG instability in HTT, possibly through different mutational mechanisms for the different haplogroups.


Asunto(s)
Pueblo Asiatico/genética , Enfermedad de Huntington/etnología , Enfermedad de Huntington/genética , Proteínas del Tejido Nervioso/genética , Proteínas Nucleares/genética , Población Blanca/genética , Haplotipos , Humanos , Proteína Huntingtina , Prevalencia
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