Juvenile polyposis of infancy in a child with deletion of BMPR1A and PTEN genes: surgical approach

Successful treatment of juvenile polyposis of infancy with sirolimus: a case report

BACKGROUND

Infantile Juvenile polyposis of infantile (JPI) is a rare and aggressive form of juvenile polyposis syndrome (JPS) typically diagnosed in the first year of life. It often carries a poor prognosis due to chronic gastrointestinal bleeding, protein-losing enteropathy, malnutrition and immune deficiency.

CASE PRESENTATION

We report a case of a girl initially presented with pallor at 7 months of age, which progressed to gastrointestinal bleeding and protein-losing enteropathy. Endoscopic examination, which included both upper gastrointestinal endoscopy and enteroscopy, showed diffuse polyposis. Histopathology results indicated the presence of juvenile polyps with no dysplasia in all removed polyps. Genetic testing identified a 2.1 Mb deletion on chromosome 10q23.2q23.31 involving the phosphatase and tensin homolog (PTEN) and bone morphogenetic protein receptor type IA (BMPR1A) genes. Treatment with sirolimus initiated at 10 months of age led to a reduction in the need for blood and albumin infusions, improved patient growth, and quality of life. While the frequency of endoscopic evaluations decreased with sirolimus, regular endoscopic polypectomy every 5 months remained necessary. However, discontinuation of sirolimus resulted in polyp recurrence after 2 months due to pneumonia.

CONCLUSION

This case highlights sirolimus treatment can alleviate many complications of JPI, it does not eliminate the need for aggressive polypectomy.

Genotype-phenotype correlation of BMPR1a disease causing variants in juvenile polyposis syndrome

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.

Diagnosis and Management of Cancer Risk in the Gastrointestinal Hamartomatous Polyposis Syndromes: Recommendations From the US Multi-Society Task Force on Colorectal Cancer

The gastrointestinal hamartomatous polyposis syndromes are rare, autosomal dominant disorders associated with an increased risk of benign and malignant intestinal and extraintestinal tumors. They include Peutz-Jeghers syndrome, juvenile polyposis syndrome, the PTEN hamartoma tumor syndrome (including Cowden's syndrome and Bannayan-Riley-Ruvalcaba syndrome), and hereditary mixed polyposis syndrome. Diagnoses are based on clinical criteria and, in some cases, confirmed by demonstrating the presence of a germline pathogenic variant. The best understood hamartomatous polyposis syndrome is Peutz-Jeghers syndrome, caused by germline pathogenic variants in the STK11 gene. The management is focused on prevention of bleeding and mechanical obstruction of the small bowel by polyps and surveillance of organs at increased risk for cancer. Juvenile polyposis syndrome is caused by a germline pathogenic variant in either the SMAD4 or BMPR1A genes, with differing clinical courses. Patients with SMAD4 pathogenic variants may have massive gastric polyposis, which can result in gastrointestinal bleeding and/or protein-losing gastropathy. Patients with SMAD4 mutations usually have the simultaneous occurrence of hereditary hemorrhagic telangiectasia (juvenile polyposis syndrome-hereditary hemorrhagic telangiectasia overlap syndrome) that can result in epistaxis, gastrointestinal bleeding from mucocutaneous telangiectasias, and arteriovenous malformations. Germline pathogenic variants in the PTEN gene cause overlapping clinical phenotypes (known as the PTEN hamartoma tumor syndromes), including Cowden's syndrome and related disorders that are associated with an increased risk of gastrointestinal and colonic polyposis, colon cancer, and other extraintestinal manifestations and cancers. Due to the relative rarity of the hamartomatous polyposis syndromes, recommendations for management are based on few studies. This U.S Multi-Society Task Force on Colorectal Cancer consensus statement summarizes the clinical features, assesses the current literature, and provides guidance for diagnosis, assessment, and management of patients with the hamartomatous polyposis syndromes, with a focus on endoscopic management.

Diagnosis and management of cancer risk in the gastrointestinal hamartomatous polyposis syndromes: recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer

The gastrointestinal hamartomatous polyposis syndromes are rare, autosomal dominant disorders associated with an increased risk of benign and malignant intestinal and extraintestinal tumors. They include Peutz-Jeghers syndrome, juvenile polyposis syndrome, the PTEN hamartoma tumor syndrome (including Cowden's syndrome and Bannayan-Riley-Ruvalcaba syndrome), and hereditary mixed polyposis syndrome. Diagnoses are based on clinical criteria and, in some cases, confirmed by demonstrating the presence of a germline pathogenic variant. The best understood hamartomatous polyposis syndrome is Peutz-Jeghers syndrome, caused by germline pathogenic variants in the STK11 gene. The management is focused on prevention of bleeding and mechanical obstruction of the small bowel by polyps and surveillance of organs at increased risk for cancer. Juvenile polyposis syndrome is caused by a germline pathogenic variant in either the SMAD4 or BMPR1A genes, with differing clinical courses. Patients with SMAD4 pathogenic variants may have massive gastric polyposis, which can result in gastrointestinal bleeding and/or protein-losing gastropathy. Patients with SMAD4 mutations usually have the simultaneous occurrence of hereditary hemorrhagic telangiectasia (juvenile polyposis syndrome-hereditary hemorrhagic telangiectasia overlap syndrome) that can result in epistaxis, gastrointestinal bleeding from mucocutaneous telangiectasias, and arteriovenous malformations. Germline pathogenic variants in the PTEN gene cause overlapping clinical phenotypes (known as the PTEN hamartoma tumor syndromes), including Cowden's syndrome and related disorders that are associated with an increased risk of gastrointestinal and colonic polyposis, colon cancer, and other extraintestinal manifestations and cancers. Due to the relative rarity of the hamartomatous polyposis syndromes, recommendations for management are based on few studies. This U.S. Multi-Society Task Force on Colorectal Cancer consensus statement summarizes the clinical features, assesses the current literature, and provides guidance for diagnosis, assessment, and management of patients with the hamartomatous polyposis syndromes, with a focus on endoscopic management.

Diagnosis and Management of Cancer Risk in the Gastrointestinal Hamartomatous Polyposis Syndromes: Recommendations From the US Multi-Society Task Force on Colorectal Cancer

The gastrointestinal hamartomatous polyposis syndromes are rare, autosomal dominant disorders associated with an increased risk of benign and malignant intestinal and extraintestinal tumors. They include Peutz-Jeghers syndrome, juvenile polyposis syndrome, the PTEN hamartoma tumor syndrome (including Cowden's syndrome and Bannayan-Riley-Ruvalcaba syndrome), and hereditary mixed polyposis syndrome. Diagnoses are based on clinical criteria and, in some cases, confirmed by demonstrating the presence of a germline pathogenic variant. The best understood hamartomatous polyposis syndrome is Peutz-Jeghers syndrome, caused by germline pathogenic variants in the STK11 gene. The management is focused on prevention of bleeding and mechanical obstruction of the small bowel by polyps and surveillance of organs at increased risk for cancer. Juvenile polyposis syndrome is caused by a germline pathogenic variant in either the SMAD4 or BMPR1A genes, with differing clinical courses. Patients with SMAD4 pathogenic variants may have massive gastric polyposis, which can result in gastrointestinal bleeding and/or protein-losing gastropathy. Patients with SMAD4 mutations usually have the simultaneous occurrence of hereditary hemorrhagic telangiectasia (juvenile polyposis syndrome-hereditary hemorrhagic telangiectasia overlap syndrome) that can result in epistaxis, gastrointestinal bleeding from mucocutaneous telangiectasias, and arteriovenous malformations. Germline pathogenic variants in the PTEN gene cause overlapping clinical phenotypes (known as the PTEN hamartoma tumor syndromes), including Cowden's syndrome and related disorders that are associated with an increased risk of gastrointestinal and colonic polyposis, colon cancer, and other extraintestinal manifestations and cancers. Due to the relative rarity of the hamartomatous polyposis syndromes, recommendations for management are based on few studies. This US Multi-Society Task Force on Colorectal Cancer consensus statement summarizes the clinical features, assesses the current literature, and provides guidance for diagnosis, assessment, and management of patients with the hamartomatous polyposis syndromes, with a focus on endoscopic management.

Gastrointestinal Polyposis in Pediatric Patients

Gastrointestinal polyps are mucosal overgrowths that, if unchecked, can undergo malignant transformation. Although relatively uncommon in the pediatric age group, they can be the harbingers of multiorgan cancer risk and require close management and follow-up. Additionally, as many polyposis syndromes are inherited, appropriate genetic testing and management of relatives is vital for the health of the entire family. In this review, we discuss both common and uncommon childhood gastrointestinal polyposis syndromes in terms of clinical presentation, management, and surveillance. We also detail any additional malignancy risk and surveillance required in the pediatric age group (<21 years old). Through this review, we provide a framework for gastroenterologists to manage the multifaceted nature of pediatric polyposis syndromes.

Successful Treatment of Juvenile Polyposis of Infancy With Sirolimus

Juvenile polyposis syndrome is a rare autosomal dominant condition characterized by multiple hamartomatous polyps throughout the gastrointestinal tract. Juvenile polyposis of infancy is a generalized severe form of juvenile polyposis syndrome associated with a poor prognosis. A 47-month-old female infant presented initially with gastrointestinal bleeding and protein-losing enteropathy at 4 months of age. At the age of 12 months, the condition worsened, requiring albumin infusions every 24 to 48 hours and red blood cell transfusions every 15 days. Upper gastrointestinal endoscopy, colonoscopy, and small-bowel enteroscopy revealed diffuse polyposis that was treated with multiple endoscopic polypectomies. Despite subtotal colectomy with ileorectal anastomosis, protein-losing enteropathy and bleeding persisted, requiring continued blood transfusions and albumin infusions. A chromosomal microarray revealed a single allele deletion in chromosome 10q23, involving both the PTEN and BMPR1A genes. Loss of PTEN function is associated with an increased activation of the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway involved in cell proliferation. Treatment with sirolimus, an mTOR inhibitor, was initiated with the aim of inhibiting polyp growth. Soon after initiation of treatment with sirolimus, blood and albumin infusions were no longer needed and resulted in improved patient growth and quality of life. This case represents the first detailed report of successful drug therapy for life-threatening juvenile polyposis of infancy.