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1.
J Genet Couns ; 33(1): 168-178, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-38197720

RESUMEN

Over the past several decades, molecular genetic testing volumes have grown and testing has expanded from single-gene assays to multigene panels, exome sequencing, and genome sequencing. The number of molecular genetic variants that require manual interpretation has grown simultaneously, resulting in an increased demand for education on molecular variant evaluation (MVE). To meet this growing need, a team of genetic counselors and educational experts undertook a quality improvement (QI) initiative with the objectives of assessing, standardizing, and scaling access to MVE education, without increasing instructor time to deliver the education. Using the Six Sigma define-measure-analyze-improve-control (DMAIC) framework, a flipped learning course with a series of standardized online modules was developed to deliver MVE education in an enduring and accessible format for a diverse group of learners. Outcome measures included the number of online modules developed, the number of individual learners and unique learner groups accessing MVE education, and direct instruction time required to deliver MVE education. Countermeasures to ensure maintenance of educational quality included post-course learner satisfaction scores and performance on competency assessments. Both the total number of learners and the number of unique learner groups accessing MVE education increased, while instructor time required to deliver content per learner decreased. Learner satisfaction scores remained constant and performance on competency assessments improved. The QI initiative successfully scaled MVE education to a diverse group of learners without decreasing learner outcomes or satisfaction. The flipped learning format provides a scalable and flexible educational model for instructors and learners in a rapidly changing environment that often includes remote work and education.


Asunto(s)
Consejeros , Mejoramiento de la Calidad , Humanos , Escolaridad , Aprendizaje
2.
JACC Case Rep ; 3(12): 1447-1452, 2021 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-34557690

RESUMEN

Small patella syndrome presents with small or absent patellae and may result in pulmonary arterial hypertension, typically in children. A pathogenic canonical splice site variant, c.1021+1G>A in the T-box transcription factor 4 (TBX4) gene, currently not included in commercial gene panel, was detected in an adult with pulmonary arterial hypertension and absent patellae. (Level of Difficulty: Advanced.).

4.
J Mol Diagn ; 20(4): 495-511, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29929942

RESUMEN

We assessed the performance characteristics of an RNA sequencing (RNA-Seq) assay designed to detect gene fusions in 571 genes to help manage patients with cancer. Polyadenylated RNA was converted to cDNA, which was then used to prepare next-generation sequencing libraries that were sequenced on an Illumina HiSeq 2500 instrument and analyzed with an in-house developed bioinformatic pipeline. The assay identified 38 of 41 gene fusions detected by another method, such as fluorescence in situ hybridization or RT-PCR, for a sensitivity of 93%. No false-positive gene fusions were identified in 15 normal tissue specimens and 10 tumor specimens that were negative for fusions by RNA sequencing or Mate Pair NGS (100% specificity). The assay also identified 22 fusions in 17 tumor specimens that had not been detected by other methods. Eighteen of the 22 fusions had not previously been described. Good intra-assay and interassay reproducibility was observed with complete concordance for the presence or absence of gene fusions in replicates. The analytical sensitivity of the assay was tested by diluting RNA isolated from gene fusion-positive cases with fusion-negative RNA. Gene fusions were generally detectable down to 12.5% dilutions for most fusions and as little as 3% for some fusions. This assay can help identify fusions in patients with cancer; these patients may in turn benefit from both US Food and Drug Administration-approved and investigational targeted therapies.


Asunto(s)
Neoplasias/genética , Fusión de Oncogenes/genética , Análisis de Secuencia de ARN/métodos , Regulación Neoplásica de la Expresión Génica , Humanos , Límite de Detección , Estabilidad del ARN/genética , ARN Neoplásico/genética , ARN Neoplásico/normas , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
5.
Histopathology ; 73(3): 514-520, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29758589

RESUMEN

AIMS: Rhabdomyosarcomas of bone are extremely rare, with fewer than 10 reported cases. A very rare subtype of spindle cell/sclerosing rhabdomyosarcoma harbouring a FUS-TFCP2 fusion and involving both soft tissue and bone locations has been reported very recently. We report only the fourth case of this unusual, clinically aggressive rhabdomyosarcoma. MATERIAL AND RESULTS: A previously well 72-year-old male presented with a destructive lesion of the mandible. Morphological and immunohistochemical study of a needle biopsy and the subsequent resection showed a spindle cell rhabdomyosarcoma. RNA-seq, RT-PCR and FISH confirmed the presence of the FUS-TFCP2 fusion. CONCLUSIONS: Spindle cell rhabdomyosarcomas carrying the FUS-TFCP2 fusion are very rare rhabdomyosarcoma variants with osseous predilection. The classification and differential diagnosis of this unusual molecular variant of spindle cell/sclerosing rhabdomyosarcoma are discussed.


Asunto(s)
Proteínas de Unión al ADN/genética , Neoplasias Mandibulares/genética , Proteínas de Fusión Oncogénica/genética , Proteína FUS de Unión a ARN/genética , Rabdomiosarcoma/genética , Factores de Transcripción/genética , Anciano , Humanos , Masculino , Neoplasias Mandibulares/patología , Rabdomiosarcoma/patología
7.
Gynecol Oncol ; 149(1): 121-126, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29402500

RESUMEN

OBJECTIVE: To increase genetic counseling referrals for patients with newly diagnosed epithelial ovarian cancer (EOC). METHODS: A practice-gap analysis was performed after measuring baseline genetic counseling referral rates to identify barriers to referral from the multidisciplinary single institution EOC care group. A Genetics Referral Toolkit consisting of a referral template, a genetic risk checklist, family history worksheet and provider and patient awareness was developed to address identified gaps with the goal of increasing referral rates. Clinical characteristics, referral placement, completion of genetic counseling/testing were abstracted for a historic cohort and intervention cohort. Data for the two cohorts were compared using chi-square, Fisher's exact test, or t-test. Association with referral was determined by univariate logistic regression. RESULTS: Eighty one patients from July through December 2013 (historic cohort) and 62 patients from July through December 2015 (intervention cohort) were identified as having a new diagnosis of EOC. Among these women, genetic counseling referral rates increased from 48.1% (39/81) in 2013 to 74.2% (46/62) in 2015 (p=0.002) after implementation of the toolkit. In a subset of patients without a previous genetic counseling referral, 87.9% (29/33) completed counseling and 79.3% (23/29) pursued testing from the historic cohort. In the intervention cohort, 60% (24/40) were seen for counseling and 100% (24/24) had testing. CONCLUSION: Application of a quality improvement process to create a Genetics Referral Toolkit increased the genetic counseling referral rate in patients with a new diagnosis of EOC. The majority of patients who were referred completed genetics consultation and elected genetic testing.


Asunto(s)
Asesoramiento Genético/métodos , Neoplasias Glandulares y Epiteliales/diagnóstico , Neoplasias Glandulares y Epiteliales/genética , Neoplasias Ováricas/diagnóstico , Neoplasias Ováricas/genética , Carcinoma Epitelial de Ovario , Estudios de Cohortes , Femenino , Asesoramiento Genético/estadística & datos numéricos , Humanos , Persona de Mediana Edad , Pautas de la Práctica en Medicina , Derivación y Consulta/estadística & datos numéricos
8.
J Genet Couns ; 25(5): 838-54, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27103422

RESUMEN

Ethical dilemmas are encountered commonly in the setting of the clinical genetic testing laboratory due to the complexity of genetic testing and the number of relevant stakeholders involved in the genetic testing process. Based on their clinical training and role within the laboratory, genetic counselors are uniquely equipped to identify and facilitate management of ethical dilemmas. This paper reviews the historical context of ethical theory and its application to the field of genetic counseling. Theoretical and applied ethics are explored in the context of dilemmas arising in the laboratory setting, with a focus on the role of the laboratory genetic counselor in managing ethical dilemmas. Two illustrative case examples are provided.


Asunto(s)
Ética Profesional , Asesoramiento Genético/ética , Pruebas Genéticas/ética , Consejeros , Humanos
9.
Genet Med ; 18(1): 13-9, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25856668

RESUMEN

Germ-line mutations in MLH1, MSH2, MSH6, and PMS2 have been shown to cause Lynch syndrome. The penetrance of the cancer and tumor spectrum has been repeatedly studied, and multiple professional societies have proposed clinical management guidelines for affected individuals. Several studies have demonstrated a reduced penetrance for monoallelic carriers of PMS2 mutations compared with the other mismatch repair (MMR) genes, but clinical management guidelines have largely proposed the same screening recommendations for all MMR gene carriers. The authors considered whether enough evidence existed to propose new screening guidelines specific to PMS2 mutation carriers with regard to age at onset and frequency of colonic screening. Published reports of PMS2 germ-line mutations were combined with unpublished cases from the authors' research registries and clinical practices, and a discussion of potential modification of cancer screening guidelines was pursued. A total of 234 monoallelic PMS2 mutation carriers from 170 families were included. Approximately 8% of those with colorectal cancer (CRC) were diagnosed before age 30, and each of these tumors presented on the left side of the colon. As it is currently unknown what causes the early onset of CRC in some families with monoallelic PMS2 germline mutations, the authors recommend against reducing cancer surveillance guidelines in families found having monoallelic PMS2 mutations in spite of the reduced penetrance.Genet Med 18 1, 13-19.


Asunto(s)
Adenosina Trifosfatasas/genética , Neoplasias Colorrectales Hereditarias sin Poliposis/genética , Enzimas Reparadoras del ADN/genética , Proteínas de Unión al ADN/genética , Detección Precoz del Cáncer/métodos , Mutación de Línea Germinal , Heterocigoto , Humanos , Endonucleasa PMS2 de Reparación del Emparejamiento Incorrecto , Penetrancia
10.
J Genet Couns ; 24(1): 6-17, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25138081

RESUMEN

The number of available genetic testing options and the nuances associated with these options continue to expand. In addition, the scope of genetic testing has broadened to areas and specialties beyond Medical Genetics. In response to these changes, diagnostic laboratories have employed genetic counselors to help navigate the increasing complexity of genetic testing, given their expertise and training in human genetics. However a largely unrecognized aspect of this role involves the use of counseling skills. Counseling skills are used by laboratory genetic counselors in a variety of situations to convey information and facilitate understanding among clinicians and medical staff. This helps to reduce test ordering errors, promote optimal test utilization, and ensure best patient care practices. The specific counseling skills used by laboratory counselors will be explored using three fictional case vignettes, followed by a discussion of the applicability of these skills in other contexts. Exploration of the unique ways in which laboratory genetic counselors apply their counseling skills can be useful for professional development and instructive for graduate training programs.


Asunto(s)
Consejo/estadística & datos numéricos , Asesoramiento Genético/estadística & datos numéricos , Pruebas Genéticas/estadística & datos numéricos , Comunicación Interdisciplinaria , Personal de Laboratorio Clínico/estadística & datos numéricos , Predisposición Genética a la Enfermedad , Humanos , Atención al Paciente/estadística & datos numéricos
11.
Genet Med ; 16(9): 711-6, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24603434

RESUMEN

PURPOSE: The Muir-Torre syndrome variant of Lynch syndrome is characterized by the presence of sebaceous neoplasms (adenoma, epithelioma/sebaceoma, carcinoma) and Lynch syndrome-associated cancers (colon, endometrial, and others). Several clinical scoring systems have been developed to identify patients with colon cancer at high risk of Lynch syndrome. However, no such system has been described for patients presenting with sebaceous neoplasms. METHODS: Based on logistic regression analysis, a scoring system was developed for patients with sebaceous neoplasm to identify those with the highest likelihood of having Muir-Torre syndrome. The final version of the scoring system included variables such as age at presentation of initial sebaceous neoplasm, total number of sebaceous neoplasms, personal history of a Lynch-related cancer, and family history of Lynch-related cancers. RESULTS: Patients with a score of 3 or more were more likely to have Muir-Torre syndrome (28 of 29 patients), those with a score of 2 had intermediate likelihood (12 of 20 patients), and no patient with a score of 0 or 1 was diagnosed with Muir-Torre syndrome. CONCLUSION: The Mayo Muir-Torre syndrome risk scoring system appears to identify whether patients who present with sebaceous neoplasms are in need of further Lynch syndrome evaluation using easily ascertained clinical information. Abnormal mismatch repair gene immunohistochemistry of a sebaceous neoplasm is a poor predictor in regard to diagnosing Lynch syndrome.


Asunto(s)
Síndrome de Muir-Torre/epidemiología , Síndrome de Muir-Torre/etiología , Riesgo , Neoplasias de las Glándulas Sebáceas/complicaciones , Adulto , Edad de Inicio , Anciano , Anciano de 80 o más Años , Comorbilidad , Femenino , Estudios de Asociación Genética , Sitios Genéticos , Mutación de Línea Germinal , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Proteína 2 Homóloga a MutS/genética , Mutación , Factores de Riesgo , Neoplasias de las Glándulas Sebáceas/diagnóstico
12.
J Mol Diagn ; 16(1): 68-74, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24184229

RESUMEN

Individuals heterozygous for the V122I mutation in transthyretin (TTR) tend to develop cardiac amyloidosis, often after the seventh decade of life. Although homozygotes have been reported, these have typically been single case reports. We report a cohort of 13 V122I homozygotes. TTR gene sequencing results from the Mayo Clinic Molecular Genetics Laboratory between September 2004 and January 2013 were reviewed; 177 heterozygotes and 13 homozygotes for the V122I alteration were identified. Detailed clinical history was available for the 24 heterozygotes seen at Mayo Clinic. We compared age at onset of disease for this group to homozygotes, both alone and pooled with the 11 homozygotes from the literature. Individuals with homozygous V122I manifested symptoms a mean of 10 years earlier than heterozygotes (63.8 ± 5.7 versus 72 ± 8.1 yrs, P = 0.0002). Further, males were significantly overrepresented in both heterozygous and homozygous individuals. There was a trend for an even higher male bias in the homozygous group. All 24 homozygotes were African American, whereas four of the heterozygotes were reported as white. Two novel V122I compound heterozygotes were also identified, with clinical presentation in the late fifth or early sixth decade of life. This study is the largest homozygous V122I cohort reported and demonstrates association with earlier age at onset. It also highlights the uncertain penetrance, particularly with respect to sex.


Asunto(s)
Neuropatías Amiloides Familiares/genética , Negro o Afroamericano/genética , Cardiomiopatías/genética , Prealbúmina/genética , Edad de Inicio , Anciano , Estudios de Cohortes , Femenino , Frecuencia de los Genes , Heterocigoto , Homocigoto , Humanos , Masculino , Persona de Mediana Edad , Mutación , Factores Sexuales
14.
Thyroid ; 23(12): 1547-52, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23461807

RESUMEN

BACKGROUND: Medullary thyroid cancer, although most commonly sporadic, may be part of the multiple endocrine neoplasia type 2 (MEN2) syndromes, generally due to mutations in the RET proto-oncogene. The majority of these mutations are located in exons 10, 11, and 13-16. More rarely, mutations in other exons have been described. We report for the first time a family from the United States with a rare mutation involving exon 8 of the RET proto-oncogene, corresponding to a p.Gly533Cys substitution (G533C) leading to the development of MEN2A syndrome in several affected family members. This mutation had only been previously described in a large family in Brazil and in 7.75% of patients with apparently sporadic medullary thyroid cancer (MTC) in Greece. METHODS: Given a strong index of suspicion, a genetic analysis to evaluate for uncommon mutations in the RET proto-oncogene identified the presence of the G533C missense mutation, despite initial negative screening for common mutations. We describe a family with a total of 47 individuals from five generations with multiple members affected with this mutation. RESULTS: Our data suggest that in patients with this mutation, pheochromocytoma is more common than previously reported, and that in some cases this mutation may be associated with a more aggressive phenotype than initially described. CONCLUSIONS: MEN2A due to the G533C mutation in exon 8 may be more common and more aggressive than previously recognized. In patients with medullary thyroid cancer with negative screening for common mutations in the RET oncogene but a strong index of suspicion, DNA sequence analysis of less commonly involved exons should be considered.


Asunto(s)
Neoplasias de las Glándulas Suprarrenales/genética , Carcinoma Medular/genética , Neoplasia Endocrina Múltiple Tipo 2a/genética , Feocromocitoma/genética , Proteínas Proto-Oncogénicas c-ret/genética , Neoplasias de la Tiroides/genética , Neoplasias de las Glándulas Suprarrenales/patología , Adulto , Anciano , Carcinoma Medular/patología , Carcinoma Neuroendocrino , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasia Endocrina Múltiple Tipo 2a/patología , Mutación , Linaje , Feocromocitoma/patología , Proto-Oncogenes Mas , Neoplasias de la Tiroides/patología
15.
J Genet Couns ; 22(3): 393-405, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23212176

RESUMEN

Screening for the Muir-Torre variant of Lynch Syndrome (LS) using Mismatch Repair (MMR) gene immunohistochemistry (IHC) on sebaceous neoplasms (SNs) is technically feasible. To date, research into the clinical utility of MMR IHC for this indication is limited. We conducted a retrospective chart review of 90 patients with MMR IHC completed on at least one SN from January 2005 to May 2010. SNs included were adenomas, epitheliomas, carcinomas and basal and squamous cell carcinomas with sebaceous differentiation. Of the 90 patients, 13 (14 %) had genetically confirmed or fulfilled clinical criteria for a diagnosis of MTS and 51 patients (57 %) presented with an abnormal MMR IHC result (loss of one or more MMR proteins) on at least one SN. Abnormal IHC had a sensitivity of 85 %, specificity of 48 %, positive predictive value (PPV) of 22 % and negative predictive value (NPV) of 95 % when evaluating for MTS. When personal or family history of colorectal cancer (≥2 family members with a history of colorectal cancer) was taken into consideration, ignoring IHC results, sensitivity was 92 %, specificity was 99 %, PPV was 92 % and NPV was 99 %. MMR IHC on SNs when used to screen for MTS has poor diagnostic utility. We recommend that MMR IHC not be performed routinely on SNs when the patient does not have either personal or family history of colorectal cancer.


Asunto(s)
Disparidad de Par Base , Síndrome de Muir-Torre/diagnóstico , Neoplasias de las Glándulas Sebáceas/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Síndrome de Muir-Torre/genética , Linaje , Estudios Retrospectivos , Neoplasias de las Glándulas Sebáceas/genética
16.
Fam Cancer ; 11(4): 667-9, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22886683

RESUMEN

Double heterozygotes for mutations in APC and a DNA mismatch repair gene are extremely rare. We report on an individual who had truncating mutations in APC and MLH1 whose clinical presentation initially resembled Familial Adenomatous Polyposis but then emerged as a novel phenotype with multiple jejunal carcinomas. We have reviewed the relevant literature on double heterozygotes and based on what has been reported to date, this phenotype was not anticipated. It may be useful for clinicians to be aware of this observation as clinical screening guidelines are proposed for such individuals.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Proteína de la Poliposis Adenomatosa del Colon/genética , Mutación de Línea Germinal/genética , Neoplasias del Yeyuno/genética , Proteínas Nucleares/genética , Humanos , Masculino , Persona de Mediana Edad , Homólogo 1 de la Proteína MutL , Pronóstico
17.
Int J Cancer ; 130(9): 2088-95, 2012 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-21671475

RESUMEN

Mutations in the mismatch repair genes cause Lynch syndrome (LS), conferring high risk of colorectal, endometrial and some other cancers. After the same splice site mutation in the MLH1 gene (c.589-2A>G) had been observed in four ostensibly unrelated American families with typical LS cancers, its occurrence in comprehensive series of LS cases (Mayo Clinic, Germany and Italy) was determined. It occurred in 10 out of 995 LS mutation carriers (1.0%) diagnosed in the Mayo Clinic diagnostic laboratory. It did not occur among 1,803 cases tested for MLH1 mutations by the German HNPCC consortium, while it occurred in three probands and an additional five family members diagnosed in Italy. In the U.S., the splice site mutation occurs on a large (∼4.8 Mb) shared haplotype that also harbors the variant c.2146G>A, which predicts a missense change in codon 716 referred to here as V716M. In Italy, it occurs on a different, shorter shared haplotype (∼2.2 Mb) that does not carry V716M. The V716M variant was found to be present by itself in the U.S., German and Italian populations with individuals sharing a common haplotype of 280 kb, allowing us to calculate that the variant arose around 5,600 years ago (225 generations; 95% confidence interval 183-272). The splice site mutation in America arose or was introduced some 450 years ago (18 generations; 95% confidence interval 14-23); it accounts for 1.0% all LS in the Unites States and can be readily screened for.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Neoplasias Colorrectales Hereditarias sin Poliposis/genética , Mutación , Proteínas Nucleares/genética , Sitios de Empalme de ARN/genética , Adulto , Anciano , Alelos , Neoplasias Colorrectales Hereditarias sin Poliposis/epidemiología , Exones/genética , Femenino , Predisposición Genética a la Enfermedad , Alemania/epidemiología , Haplotipos , Heterocigoto , Humanos , Intrones/genética , Italia/epidemiología , Masculino , Persona de Mediana Edad , Homólogo 1 de la Proteína MutL , Polimorfismo de Nucleótido Simple , Estados Unidos/epidemiología
18.
J Genet Couns ; 20(4): 327-9, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21448764

RESUMEN

We are reporting what we believe to be the first published case of patient initiated direct to consumer (DTC) genetic testing to test for the presence of a known familial mutation. Our client in this case is from a known MSH2 family; both his/her parent and associated grandparent have previously tested positive for the known familial MSH2 mutation. Using 23andme's "family inheritance genome-wide comparison" option we were able to determine that our client most likely inherited the known familial MSH2 mutation without pursuing single site genetic testing. Our client pursued DTC genetic testing instead of single site genetic testing due to the fear of genetic discrimination. This case shows that patients are still fearful of genetic discrimination, despite the passage of the Genetic Information Nondiscrimination Act (GINA), and that DTC genetic testing may be useful despite the overall negative feeling towards this type of testing in the genetic counseling community.


Asunto(s)
Neoplasias Colorrectales Hereditarias sin Poliposis/diagnóstico , Pruebas Genéticas/métodos , Participación del Paciente , Neoplasias Colorrectales Hereditarias sin Poliposis/genética , Femenino , Humanos , Masculino , Linaje
19.
J Mol Diagn ; 13(1): 93-9, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21227399

RESUMEN

Lynch syndrome is an autosomal dominant cancer predisposition syndrome characterized by loss of function of DNA mismatch repair enzyme MLH1, MSH2, MSH6, or PMS2. Mutations in MLH1 and MSH2 account for ∼80% of the inherited cases. However, in up to 20% of cases suspected of having a germline mutation in MSH2 due to loss of MSH2 expression, a germline mutation is not identified. Recent studies have shown that some Lynch syndrome cases are due to 3' EPCAM/TACSTD1 deletions that subsequently lead to MSH2 promoter hypermethylation. In this study, we examined the frequency of this novel mechanism for MSH2 inactivation in cases recruited through the Colon Cancer Family Registry and from the Mayo Clinic Molecular Diagnostics Laboratory. From the combined cohort, 58 cases were selected in which immunohistochemical staining suggested a mutation in MSH2 or MSH6, but no mutations were identified on follow-up testing. Of these 58 cases, 11 demonstrated a deletion of EPCAM/TACSTD1. Of cases with a deletion, the methylation status of the MSH2 promoter was confirmed in tumor tissue using methylation-sensitive PCR primers. One case showed MSH2 promoter hypermethylation in the absence of a detectable EPCAM/TACSTD1 deletion. These results indicate that approximately 20% to 25% of cases suspected of having a mutation in MSH2 but in which a germline mutation is not detected, can be accounted for by germline deletions in EPCAM/TACSTD1. These data also suggest the presence of other alterations leading to MSH2 promoter hypermethylation.


Asunto(s)
Antígenos de Neoplasias/genética , Moléculas de Adhesión Celular/genética , Neoplasias Colorrectales Hereditarias sin Poliposis/genética , Proteína 2 Homóloga a MutS/genética , Eliminación de Secuencia , Adulto , Anciano , Neoplasias del Colon/genética , Metilación de ADN , Reparación de la Incompatibilidad de ADN , Molécula de Adhesión Celular Epitelial , Femenino , Humanos , Reacción en Cadena de la Ligasa , Masculino , Inestabilidad de Microsatélites , Persona de Mediana Edad , Regiones Promotoras Genéticas
20.
Cancer Res ; 68(7): 2145-53, 2008 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-18381419

RESUMEN

Large germline deletions within the mismatch repair gene MSH2 account for a significant proportion (up to 20%) of all deleterious mutations of this gene which are associated with Lynch syndrome. An exons 1 to 6 deletion of MSH2, originally reported in nine families, has been associated with a founding event within the United States, which genealogic studies had previously dated to 1727, and the number of present day carriers was estimated to be 18,981. Here, we report the development of a robust multiplex PCR which has assisted in the detection of 32 new families who carry the MSH2 American Founder Mutation (AFM). By offering testing to family members, 126 carriers of the AFM have been identified. Extensive genealogic studies have connected 27 of the 41 AFM families into seven extended pedigrees. These extended families have been traced back to around the 18th century without any evidence of further convergence between them. Characterization of the genomic sequence flanking the deletion and the identification of a common disease haplotype of between 0.6 and 2.3 Mb in all probands provides evidence for a common ancestor between these extended families. The DMLE+2.2 software predicts an age of approximately 500 years (95% confidence interval, 425-625) for this mutation. Taken together, these data are suggestive of an earlier founding event than was first thought, which likely occurred in a European or a Native American population. The consequences of this finding would be that the AFM is significantly more frequent in the United States than was previously predicted.


Asunto(s)
Neoplasias Colorrectales Hereditarias sin Poliposis/genética , Efecto Fundador , Proteína 2 Homóloga a MutS/genética , Alelos , Secuencia de Bases , Neoplasias Colorrectales Hereditarias sin Poliposis/epidemiología , Femenino , Genotipo , Mutación de Línea Germinal , Haplotipos , Humanos , Masculino , Datos de Secuencia Molecular , Linaje , Reacción en Cadena de la Polimerasa/métodos , Prevalencia , Estados Unidos/epidemiología
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