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Wu MY, Toon C, Field M, Wong M. Polyposis found on index colonoscopy in a 56-year-old female - BMPR1A variant in juvenile polyposis syndrome: A case report. World J Gastrointest Endosc 2023; 15:623-628. [PMID: 37900118 PMCID: PMC10600688 DOI: 10.4253/wjge.v15.i10.623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/21/2023] [Accepted: 07/31/2023] [Indexed: 10/12/2023] Open
Abstract
BACKGROUND Juvenile polyposis syndrome (JPS) is a rare hereditary polyposis disease frequently associated with an autosomal-dominant variant of the SMAD4 or BMPR1A gene. It often manifests with symptoms in children and adolescents and is infrequently diagnosed in asymptomatic adults. Establishing the diagnosis is important as patients with JPS have a high risk of developing gastrointestinal cancer and require genetic counselling and close routine follow-up. CASE SUMMARY We report on the case of a 56-year-old female diagnosed with JPS after genetic testing revealed a rare variant of the BMPR1A gene BMPR1A c.1409T>C (p.Met470Thr). She was initially referred for colonoscopy by her general practitioner after testing positive on a screening faecal immunochemical test and subsequently found to have polyposis throughout the entire colorectum on her index screening colonoscopy. The patient was asymptomatic with a normal physical examination and no related medical or family history. Blood tests revealed only mild iron deficiency without anemia. To date, there has only been one other reported case of JPS with the same genetic variant. Subsequent colonoscopies were organised for complete polyp clearance and the patient was returned for surveillance follow-up. CONCLUSION JPS patients can present with no prior symptoms or family history. Genetic testing plays an important diagnostic role guiding management.
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Affiliation(s)
- Michael Yulong Wu
- Department of Gastroenterology and Hepatology, Royal North Shore Hospital, Sydney 2065, New South Wales, Australia
- Northern Clinical School, The University of Sydney, Sydney 2065, New South Wales, Australia
| | - Christopher Toon
- NSW Health Pathology, Department of Anatomical Pathology, Royal North Shore Hospital, Sydney 2065, New South Wales, Australia
| | - Michael Field
- Clinical Genetics, Royal North Shore Hospital, Sydney 2065, New South Wales, Australia
| | - May Wong
- Department of Gastroenterology and Hepatology, Royal North Shore Hospital, Sydney 2065, New South Wales, Australia
- Northern Clinical School, The University of Sydney, Sydney 2065, New South Wales, Australia
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Papadopulos ME, Plazzer JP, Macrae FA. Genotype-phenotype correlation of BMPR1a disease causing variants in juvenile polyposis syndrome. Hered Cancer Clin Pract 2023; 21:12. [PMID: 37400896 DOI: 10.1186/s13053-023-00255-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 06/07/2023] [Indexed: 07/05/2023] Open
Abstract
BACKGROUND Juvenile Polyposis Syndrome (JPS) is an autosomal dominant condition with hamartomatous polyps in the gastrointestinal tract, associated with an increased risk of gastrointestinal malignancy. Disease causing variants (DCVs) in BMPR1a or SMAD4 account for 45-60% of JPS cases, with BMPR1a DCVs accounting for 17-38% of JPS cases. Within those with either a BMPR1a or SMAD4 DCV, there is phenotypic variability in location of polyps, risk of malignancy and extra-intestinal manifestations with limited published reports of gene-phenotype association or genotype-phenotype correlation. We aimed to identify any gene-phenotype association or genotype-phenotype correlation in BMPR1a to inform surveillance recommendations, and gene-specific modification to the ACMG classification of pathogenicity of DCVs. METHODS A literature search was performed through EMBASE, MEDLINE and PubMed. Studies that were included explored BMPR1a DCV-related JPS or contiguous deletion of PTEN and BMPR1a. Data was also drawn from the BMPR1a specific databases on LOVD and ClinVar. RESULTS There were 211 DCVs in BMPR1a identified, 82 from patients with JPS in the literature, and 17 from LOVD and 112 from ClinVar classified as pathogenic or likely pathogenic. These included missense, nonsense and frameshift variants and large deletions, occurring across all functional domains of the gene. Unlike in SMAD4 carriers, gastric polyposis and malignancy were not identified in our review in BMPR1a carriers, but colonic polyposis and malignancy occurred in carriers of either BMPR1a or SMAD4 DCVs. Those with contiguous deletion of PTEN and BMPR1a can present with JPS of infancy, with a severe phenotype of GI bleeding, diarrhoea, exudative enteropathy and rectal prolapse. No specific BMPR1a genotype-phenotype correlation could be ascertained including by variant type or functional domain. CONCLUSION Phenotypic characteristics cannot be used to inform variant location in BMPR1a. However, the phenotypic characteristics of BMPR1a DCV carriers, being almost exclusively related to the colon and rectum, can assist in pathogenicity assessment of BMPR1a variants. Given these findings, we propose that carriers of BMPR1a DCVs should only require surveillance for colorectal polyps and malignancy, and that surveillance for gastric polyps and malignancy may be unnecessary. However variant location within BMPR1a does not support differential surveillance recommendations.
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Affiliation(s)
- M E Papadopulos
- Department of Medicine, University of Melbourne, The Royal Melbourne Hospital, Melbourne, Australia.
- Department of Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Melbourne, Australia.
| | - J P Plazzer
- Department of Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Melbourne, Australia
| | - F A Macrae
- Department of Medicine, University of Melbourne, The Royal Melbourne Hospital, Melbourne, Australia
- Department of Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Melbourne, Australia
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Liu Q, Liu M, Liu T, Yu Y. Familial juvenile polyposis syndrome with a de novo germline missense variant in BMPR1A gene: a case report. BMC MEDICAL GENETICS 2020; 21:196. [PMID: 33032550 PMCID: PMC7545562 DOI: 10.1186/s12881-020-01135-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 09/28/2020] [Indexed: 11/10/2022]
Abstract
Background Juvenile polyposis syndrome (JPS) is a rare autosomal dominant hereditary disorder characterized by the development of multiple distinct juvenile polyps in the gastrointestinal tract with an increased risk of colorectal cancer. Germline mutations in two genes, SMAD4 and BMPR1A, have been identified to cause JPS. Case presentation Here, we report a germline heterozygous missense variant (c.299G > A) in exon 3 BMPR1A gene in a family with juvenile polyposis. This variant was absent from the population database, and concluded as de novo compared with the parental sequencing. Further sequencing of the proband’s children confirmed the segregation of this variant with the disease, while the variant was also predicted to have damaging effect based on online prediction tools. Therefore, this variant was classified as likely pathogenic according to the American College of Medical Genetics and Genomics (ACMG) guidelines. Conclusions Germline genetic testing revealed a de novo germline missense variant in BMPR1A gene in a family with juvenile polyposis. Identification of the pathogenic variant facilitates the cancer risk management of at-risk family members, and endoscopic surveillance is recommended for mutation carriers.
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Affiliation(s)
- Qing Liu
- Department of Medical Oncology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China
| | - Mengling Liu
- Department of Medical Oncology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China
| | - Tianshu Liu
- Department of Medical Oncology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China
| | - Yiyi Yu
- Department of Medical Oncology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.
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Rohlin A, Rambech E, Kvist A, Törngren T, Eiengård F, Lundstam U, Zagoras T, Gebre-Medhin S, Borg Å, Björk J, Nilbert M, Nordling M. Expanding the genotype-phenotype spectrum in hereditary colorectal cancer by gene panel testing. Fam Cancer 2017; 16:195-203. [PMID: 27696107 PMCID: PMC5357488 DOI: 10.1007/s10689-016-9934-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hereditary syndromes causing colorectal cancer include both polyposis and non-polyposis syndromes. Overlapping phenotypes between the syndromes have been recognized and this make targeted molecular testing for single genes less favorable, instead there is a gaining interest for multi-gene panel-based approaches detecting both SNVs, indels and CNVs in the same assay. We applied a panel including 19 CRC susceptibility genes to 91 individuals of six phenotypic subgroups. Targeted NGS-based sequencing of the whole gene regions including introns of the 19 genes was used. The individuals had a family history of CRC or had a phenotype consistent with a known CRC syndrome. The purpose of the study was to demonstrate the diagnostic difficulties linked to genotype-phenotype diversity and the benefits of using a gene panel. Pathogenicity classification was carried out on 46 detected variants. In total we detected sixteen pathogenic or likely pathogenic variants and 30 variants of unknown clinical significance. Four of the pathogenic or likely pathogenic variants were found in BMPR1A in patients with unexplained familial adenomatous polyposis or atypical adenomatous polyposis, which extends the genotype-phenotype spectrum for this gene. Nine patients had more than one variant remaining after the filtration, including three with truncating mutations in BMPR1A, PMS2 and AXIN2. CNVs were found in three patients, in upstream regions of SMAD4, MSH3 and CTNNB1, and one additional individual harbored a 24.2 kb duplication in CDH1 intron1.
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Affiliation(s)
- Anna Rohlin
- Department of Molecular and Clinical Genetics, Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
| | - Eva Rambech
- Division of Oncology and Pathology Department of Clinical Sciences Lund, Lund University, Medicon Village, 22381, Lund, Sweden
| | - Anders Kvist
- Division of Oncology and Pathology Department of Clinical Sciences Lund, Lund University, Medicon Village, 22381, Lund, Sweden
| | - Therese Törngren
- Division of Oncology and Pathology Department of Clinical Sciences Lund, Lund University, Medicon Village, 22381, Lund, Sweden
| | - Frida Eiengård
- Department of Molecular and Clinical Genetics, Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Ulf Lundstam
- Department of Surgery, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospital/Östra, 416 85, Gothenburg, Sweden
| | - Theofanis Zagoras
- Department of Molecular and Clinical Genetics, Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Samuel Gebre-Medhin
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden
- Department of Clinical Genetics, Office for Medical Services, Division of Laboratory Medicine, Lund, Sweden
| | - Åke Borg
- Division of Oncology and Pathology Department of Clinical Sciences Lund, Lund University, Medicon Village, 22381, Lund, Sweden
| | - Jan Björk
- The Swedish Polyposis Registry, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Mef Nilbert
- Division of Oncology and Pathology Department of Clinical Sciences Lund, Lund University, Medicon Village, 22381, Lund, Sweden
- The HNPCC-register, Hvidovre University Hospital, Copenhagen University, Hvidovre, Denmark
| | - Margareta Nordling
- Department of Molecular and Clinical Genetics, Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
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Hover LD, Abel TW, Owens P. Genomic Analysis of the BMP Family in Glioblastomas. TRANSLATIONAL ONCOGENOMICS 2015; 7:1-9. [PMID: 25987829 PMCID: PMC4406393 DOI: 10.4137/tog.s22256] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/22/2015] [Accepted: 01/29/2015] [Indexed: 12/29/2022]
Abstract
Glioblastoma multiforme (GBM) is a grade IV glioma with a median survival of 15 months. Recently,
bone morphogenetic protein (BMP) signaling has been shown to promote survival in xenograft murine
models. To gain a better understanding of the role of BMP signaling in human GBMs, we examined the
genomic alterations of 90 genes associated with BMP signaling in GBM patient samples. We completed
this analysis using publically available datasets compiled through The Cancer Genome Atlas and the
Glioma Molecular Diagnostic Initiative. Here we show how mRNA expression is altered in GBM samples
and how that is associated with patient survival, highlighting both known and novel associations
between BMP signaling and GBM biology.
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Affiliation(s)
- Laura D Hover
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Ty W Abel
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Philip Owens
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN, USA
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Abstract
The autosomal dominantly inherited juvenile polyposis syndrome (JPS) leads to the development of multiple hamartomatous polyps in the gastrointestinal tract and is a precancerous condition. In a large family with a newly identified SMAD4 mutation (c.543delC), we describe the clinical manifestations of JPS. Nine affected SMAD4 mutation-positive family members were screened and treated for manifestations of JPS. Two family members were symptomatic at the time of diagnosis; seven were asymptomatic - independent of the severity of the manifestation. Each mutation carrier presented with colonic juvenile polyps, seven out of nine with additional gastric manifestations. One asymptomatic patient had early gastric cancer; another patient had a villous adenoma with high-grade intraepithelial neoplasia in the colon. Three patients had biliary lesions including a bile duct hamartoma in one and gallbladder polyps in two. Three patients had gastrointestinal vascular malformations. All mutation carriers were affected by JPS. Interestingly, the manifestations and their severity differed considerably between the patients, suggesting secondary factors influencing JPS manifestations such as Helicobacter pylori infection.
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Le VQ, Wharton KA. Hyperactive BMP signaling induced by ALK2(R206H) requires type II receptor function in a Drosophila model for classic fibrodysplasia ossificans progressiva. Dev Dyn 2012; 241:200-14. [PMID: 22174087 DOI: 10.1002/dvdy.22779] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Fibrodysplasia Ossificans Progressiva (FOP) is an autosomal dominant disorder characterized by episodic deposition of heterotopic bone in place of soft connective tissue. All FOP-associated mutations map to the BMP type I receptor, ALK2, with the ALK2(R206H) mutant form found in the vast majority of patients. The mechanism(s) regulating the expressivity of hyperactive ALK2(R206H) signaling throughout a patient's life is not well understood. RESULTS In Drosophila, human ALK2(R206H) receptor induces hyperactive BMP signaling. As in vertebrates, elevated signaling associated with ALK2(R206H) in Drosophila is ligand-independent. We found that a key determinant for ALK2(R206H) hyperactivity is a functional type II receptor. Furthermore, our results indicate that like its Drosophila ortholog, Saxophone (Sax), wild-type ALK2 can antagonize, as well as promote, BMP signaling. CONCLUSIONS The dual function of ALK2 is of particular interest given the heterozygous nature of FOP, as the normal interplay between such disparate behaviors could be shifted by the presence of ALK2(R206H) receptors. Our studies provide a compelling example for Drosophila as a model organism to study the molecular underpinnings of complex human syndromes such as FOP.
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Affiliation(s)
- Viet Q Le
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912, USA
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9
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Functional analysis of saxophone, the Drosophila gene encoding the BMP type I receptor ortholog of human ALK1/ACVRL1 and ACVR1/ALK2. Genetics 2009; 183:563-79, 1SI-8SI. [PMID: 19620392 DOI: 10.1534/genetics.109.105585] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In metazoans, bone morphogenetic proteins (BMPs) direct a myriad of developmental and adult homeostatic events through their heterotetrameric type I and type II receptor complexes. We examined 3 existing and 12 newly generated mutations in the Drosophila type I receptor gene, saxophone (sax), the ortholog of the human Activin Receptor-Like Kinase1 and -2 (ALK1/ACVRL1 and ALK2/ACVR1) genes. Our genetic analyses identified two distinct classes of sax alleles. The first class consists of homozygous viable gain-of-function (GOF) alleles that exhibit (1) synthetic lethality in combination with mutations in BMP pathway components, and (2) significant maternal effect lethality that can be rescued by an increased dosage of the BMP encoding gene, dpp+. In contrast, the second class consists of alleles that are recessive lethal and do not exhibit lethality in combination with mutations in other BMP pathway components. The alleles in this second class are clearly loss-of-function (LOF) with both complete and partial loss-of-function mutations represented. We find that one allele in the second class of recessive lethals exhibits dominant-negative behavior, albeit distinct from the GOF activity of the first class of viable alleles. On the basis of the fact that the first class of viable alleles can be reverted to lethality and on our ability to independently generate recessive lethal sax mutations, our analysis demonstrates that sax is an essential gene. Consistent with this conclusion, we find that a normal sax transcript is produced by saxP, a viable allele previously reported to be null, and that this allele can be reverted to lethality. Interestingly, we determine that two mutations in the first class of sax alleles show the same amino acid substitutions as mutations in the human receptors ALK1/ACVRl-1 and ACVR1/ALK2, responsible for cases of hereditary hemorrhagic telangiectasia type 2 (HHT2) and fibrodysplasia ossificans progressiva (FOP), respectively. Finally, the data presented here identify different functional requirements for the Sax receptor, support the proposal that Sax participates in a heteromeric receptor complex, and provide a mechanistic framework for future investigations into disease states that arise from defects in BMP/TGF-beta signaling.
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Calva-Cerqueira D, Chinnathambi S, Pechman B, Bair J, Larsen-Haidle J, Howe JR. The rate of germline mutations and large deletions of SMAD4 and BMPR1A in juvenile polyposis. Clin Genet 2008; 75:79-85. [PMID: 18823382 DOI: 10.1111/j.1399-0004.2008.01091.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Juvenile polyposis (JPS) is an autosomal dominant syndrome that predisposes individuals to develop gastrointestinal polyps and cancer. Germline point mutations in SMAD4 and BMPR1A have been identified as causing JPS in approximately 40-60% of patients, but few studies have looked at the rate of large deletions. In this study, we determined the overall prevalence of genetic changes of SMAD4 and BMPR1A by sequencing and by screening for larger deletions. DNA was extracted from 102 JPS probands, and each exon and intron-exon boundary of SMAD4 and BMPR1A were sequenced. Coding and non-coding exons of SMAD4 and BMPR1A were screened for deletions with multiplex ligation-dependent probe amplification (MLPA). By sequencing, 20 probands had point mutations of SMAD4 and 22 of BMPR1A. By MLPA, one proband had deletion of most of SMAD4, one of both BMPR1A and PTEN, one of the 5' end of BMPR1A, and another of the 5' end of SMAD4. The overall prevalence of SMAD4 and BMPR1A point mutations and deletions in JPS was 45% in the largest series of patients to date. Large deletions are less frequent in JPS patients, but represent other heritable causes of JPS, which should be screened for in pre-symptomatic genetic testing.
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Affiliation(s)
- D Calva-Cerqueira
- Department of Surgery, University of Iowa Carver College of Medicine, Iowa City, IA, USA
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Abstract
Since the histologic description of the hamartomatous polyp in 1957 by Horrilleno and colleagues, descriptions have appeared of several different syndromes with the propensity to develop these polyps in the upper and lower gastrointestinal tracts. These syndromes include juvenile polyposis, Peutz-Jeghers syndrome, hereditary mixed polyposis syndrome, and the phosphatase and tensin homolog gene (PTEN) hamartoma tumor syndromes (Cowden and Bannayan-Riley-Ruvalcaba syndromes), which are autosomal-dominantly inherited, and Cronkhite-Canada syndrome, which is acquired. This article reviews the clinical aspects, the molecular pathogenesis, the affected organ systems, the risks of cancer, and the management of these hamartomatous polyposis syndromes. Although the incidence of these syndromes is low, it is important for clinicians to recognize these disorders to prevent morbidity and mortality in these patients, and to perform presymptomatic testing in patients at risk.
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Affiliation(s)
- Daniel Calva
- Resident in Surgery, Roy J. and Lucille A. Carver University of Iowa College of Medicine, Iowa City, IA
| | - James R. Howe
- Professor of Surgery, Chief, Division of Surgical Oncology and Endocrine Surgery, Roy J. and Lucille A. Carver University of Iowa College of Medicine; Iowa City, IA
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Chow E, Lipton L, Carvajal-Carmona LG, Arthur G, Bhathal P, Kaur G, Jaeger E, Woodford-Richens K, Howarth K, Tomlinson I, Macrae F. A family with juvenile polyposis linked to the BMPR1A locus: cryptic mutation or closely linked gene? J Gastroenterol Hepatol 2007; 22:2292-7. [PMID: 17573831 DOI: 10.1111/j.1440-1746.2007.04989.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND AND AIM Familial juvenile polyposis syndrome (JPS) is a rare autosomal dominant condition in which patients develop hamartomatous gastrointestinal polyps with malignant potential. Pathogenic germline mutations in both the SMAD4 and BMPR1A genes involved in the transforming growth factor beta pathway account for 40% of cases of JPS. Genetic heterogeneity remains evident, as the balance of cases is not accounted for by mutations in these genes. The aim of this study was to determine the mutation responsible in a family with juvenile polyposis. METHODS An Australian Caucasian family with juvenile polyposis have attended and followed surveillance plans through the Familial Bowel Cancer Clinic, The Royal Melbourne Hospital. A pedigree of the family was constructed with attention to the mixed phenotypic expression of polyps in affected members. Genetic testing for SMAD4 and BMPR1A mutations in germline DNA and linkage analysis to SMAD4, BMPR1A and 15q14 (CRAC1 locus) were performed. RESULTS There were no pathogenic mutations in SMAD4 and BMPR1A. There was no linkage to SMAD4 or 15q14 (CRAC1 locus). Linkage analysis suggested a cryptic BMPR1A mutation or the presence of another gene in close proximity to the BMPR1A locus. Two additional candidate genes in the region of linkage (PTEN and MINPP1) were excluded. CONCLUSION Most affected members of this Australian Caucasian family demonstrate a phenotype of mixed polyps: juvenile polyps, adenomas and/or hyperplastic polyps. Cloning of a potentially responsible gene closely linked to the BMPR1A locus or a cryptic mutation in BMPR1A may offer valuable insights into the pathogenesis of JPS.
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Affiliation(s)
- Elizabeth Chow
- Department of Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Melbourne, Victoria, Australia.
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Abstract
Juvenile Polyposis Syndrome is an uncommon hamartomatous disorder with significant gastrointestinal malignant potential. Mutations in SMAD4 and BMPR1A, implicated in the Transforming Growth Factor beta pathway, have recently been characterized, and hold significance in the management of patients and at risk family members. This article reviews our knowledge to date of the genetics and clinicopathological features of the Juvenile Polyposis Syndrome, and discusses the current expert recommendations for genetic testing, disease screening and management.
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Affiliation(s)
- Elizabeth Chow
- Department of Colorectal Medicine and Genetics, Royal Melbourne Hospital, Victoria, Australia.
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Fogt F, Brown CA, Badizadegan K, Zimmerman RL, Odze R. Low prevalence of loss of heterozygosity and SMAD4 mutations in sporadic and familial juvenile polyposis syndrome-associated juvenile polyps. Am J Gastroenterol 2004; 99:2025-31. [PMID: 15447767 DOI: 10.1111/j.1572-0241.2004.30502.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Juvenile polyps (JP) may develop sporadically or may be associated with the familial juvenile polyposis syndrome (FJPS). In FJPS, the epithelium is susceptible to dysplasia and, ultimately adenocarcinoma. However, the mechanisms involved in this transformation are unknown. Since the epithelium in colorectal carcinogenesis undergoes a stepwise genetic progression, the purpose of this study was to determine if loss of heterozygosity (LOH) abnormalities can aid in the differentiation between sporadic and FJPS-associated polyps. DESIGN Ninety-one routinely-processed JP from three groups of patients were evaluated for this study. Group 1 included 39 polyps from 39 patients with a single JP and no personal or family history of FJPS; group 2 consisted of 24 polyps from 15 patients with 2-5 JP and no history of FJPS; and group 3 included 29 polyps from 22 patients with > or =5 polyps either with (7) or without (15) a family history of FJPS. Epithelium from typical, atypical, and overtly dysplastic polyps, when present (2 cases in group 3 only), were evaluated separately by microdissection and PCR analysis for LOH of APC, p53, 3p, 9p, and mutations in exon 9 of the SMAD4 gene. RESULTS SMAD4 mutations were observed in 3 polyps from 2 patients in group 3 (10% of informative cases; p < 0.05 vs group 1), but not in any of the polyps from the other two groups. Overall, LOH of APC, p53, 3p, and 9p were detected in 1%, 15%, 10%, and 4% of JPs, but no differences were observed between the three clinical groups. Two polyps, both in group 3, with definite dysplasia did not show any genetic alterations. The morphologic appearance of the polyps was not a reliable feature in helping to differentiate sporadic from FJPS-associated polyps. CONCLUSIONS LOH of APC, p53, 3p, and 9p may not be involved in the carcinogenic pathway of FJPS-associated polyps. SMAD4 gene mutations show a low sensitivity but a high specificity for FJPS.
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Affiliation(s)
- Franz Fogt
- Department of Pathology, University of Pennsylvania, Presbyterian Medical Center, 39th and Market Streets, Philadelphia, PA 19104, USA
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Ming Kwan K, Li AG, Wang XJ, Wurst W, Behringer RR. Essential roles of BMPR-IA signaling in differentiation and growth of hair follicles and in skin tumorigenesis. Genesis 2004; 39:10-25. [PMID: 15124223 DOI: 10.1002/gene.20021] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Hair differentiation and growth are controlled by complex reciprocal signaling between epithelial and mesenchymal cells. To better understand the requirement and molecular mechanism of BMP signaling in hair follicle development, we performed genetic analyses of bone morphogenetic protein receptor 1A (BMPR-IA) function during hair follicle development by using a conditional knockout approach. The conditional mutation of Bmpr1a in ventral limb ectoderm and its derivatives (epidermis and hair follicles) resulted in a lack of hair outgrowth from the affected skin regions. Mutant hair follicles exhibited abnormal morphology and lacked hair formation and pigment deposition during anagen. The timing of the hair cycle and the proliferation of hair matrix cells were also affected in the mutant follicles. We demonstrate that signaling via epithelial BMPR-IA is required for differentiation of both hair shaft and inner root sheath from hair matrix precursor cells in anagen hair follicles but is dispensable for embryonic hair follicle induction. Surprisingly, aberrant de novo hair follicle morphogenesis together with hair matrix cell hyperplasia was observed in the absence of BMPR-IA signaling within the affected skin of adult mutants. They developed hair follicle tumors from 3 months of age, indicating that inactivation of epidermal BMPR-IA signaling can lead to hair tumor formation. Taken together, our data provide genetic evidence that BMPR-IA signaling plays critical and multiple roles in controlling cell fate decisions or maintenance, proliferation, and differentiation during hair morphogenesis and growth, and implicate Bmpr1a as a tumor suppressor in skin tumorigenesis.
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Affiliation(s)
- Kin Ming Kwan
- Department of Molecular Genetics, University of Texas M D Anderson Cancer Center, Houston, Texas 77030, USA
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