Polyposis found on index colonoscopy in a 56-year-old female-BMPR1A variant in juvenile polyposis syndrome:A case report

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.

Juvenile polyposis syndrome

Juvenile polyposis syndrome is a rare autosomal dominant syndrome characterized by multiple distinct juvenile polyps in the gastrointestinal tract and an increased risk of colorectal cancer.The cumulative life-time risk of colorectal cancer is 39% and the relative risk is 34.Juvenile polyps have a distinctive histology characterized by an abundance of edematous lamina propria with inflammatory cells and cystically dilated glands lined by cuboidal to columnar epithelium with reactive changes.Clinically,juvenile polyposis syndrome is defined by the presence of 5 or more juvenile polyps in the colorectum,juvenile polyps throughout the gastrointestinal tract or any number of juvenile polyps and a positive family history of juvenile polyposis.In about 50%-60% of patients diagnosed with juvenile polyposis syndrome a germline mutation in the SMAD4 or BMPR1A gene is found.Both genes play a role in the BMP/TGF-beta signalling pathway.It has been suggested that cancer in juvenile polyposis may develop through the socalled "landscaper mechanism" where an abnormal stromal environment leads to neoplastic transformation of the adjacent epithelium and in the end invasive carcinoma.Recognition of this rare disorder is important for patients and their families with regard to treatment,follow-up and screening of at risk individuals.Each clinician confronted with the diagnosis of a juvenile polyp should therefore consider the possibility of juvenile polyposis syndrome.In addition,juvenile polyposis syndrome provides a unique model to study colorectal cancer pathogenesis in general and gives insight in the molecular genetic basis of cancer.This review discusses clinical manifestations,genetics,pathogenesis and management of juvenile polyposis syndrome.

Hereditary polyposis syndromes remain a challenging disease entity:Old dilemmas and new insights

In this editorial we present an overview and insights of the management of hereditary polyposis syndromes.The primary focus was on familial adenomatous polyposis,juvenile polyposis syndrome and Peutz-Jegher syndrome.Genetic testing has become increasingly available and is easier than ever to integrate into clinical practice.Furthermore,several genes have been added to the expanding list of genes associated with hereditary polyposis syndromes,allowing for precise diagnostics and tailored follow-up.Endoscopic evaluation of patients with hereditary polyposis syndromes is paramount in the surveillance strategies.Current endoscopic procedures include both diagnostic procedures and surveillance as well as therapeutic interventions.Recommendations for endoscopic procedures in the upper and lower gastrointestinal canal were described.Surgery is still a key component in the management of patients with hereditary polyposis syndromes.The increased cancer risk in these patients often render prophylactic procedures or intended curative procedures in the case of cancer development.Surgical interventions in the upper and lower gastrointestinal canal were described with relevant considerations.Development of chemopreventive medications is ongoing.Few drugs have been investigated,including nonsteroidal anti-inflammatory drugs.It has been demonstrated that cyclooxygenase-2 inhibitors may lower the number of polyps.Other medications are currently under investigation,but none have,to date,consistently been able to prevent development of disease.

Re-recognition of BMPR1A-related polyposis:beyond juvenile polyposis and hereditary mixed polyposis syndrome

Background Bone morphogenetic protein receptor type 1A(BMPR1A)is responsible for two individual Mendelian diseases:juvenile polyposis syndrome and hereditary mixed polyposis syndrome 2,which have overlapping phenotypes.This study aimed to elucidate whether these two syndromes are just two subtypes of a single syndrome rather than two isolated syndromes.Methods We sequenced the BMPR1A gene in 186 patients with polyposis and colorectal cancer,and evaluated the clinicopathological features and phenotypes of the probands and their available relatives with BMPR1A mutations.Results BMPR1A germline mutations were found in six probands and their three available relatives.The numbers of frameshift,nonsense,splice-site,andmissensemutations were one,one,two,and two,respectively;two of the sixmutations were novel.Typical juvenile polyps were found in only three patients.Two patients had colorectal cancer rather than any polyps.Conclusions Diseases in BMPR1A germline mutation carriers vary from mixed polyposis to sole colorectal cancer,and typical juvenile polyps do not always occur in these carriers.The variety of phenotypes reflected the features of BMPR1Amutation carriers,which should be recognized as a spectrum of one syndrome.Genetic testing may be a good approach to identifying BMPR1A-related syndromes.

Hamartomatous polyps:Diagnosis,surveillance,and management

Hereditary polyposis syndrome can be divided into three categories:Adenomatous,serrated,and hamartomatous polyps.Hamartomatous polyps,malformations of normal tissue presenting in a disorganized manner,are characterized by an autosomal dominant inheritance pattern.These syndromes exhibit hamartomatous gastrointestinal polyps in conjunction to extra-intestinal manifestations,which require conscientious and diligent monitoring.Peutz-Jeghers syndrome,Cowden syndrome,and juvenile polyposis syndrome are the most common displays of hamartomatous polyposis syndrome(HPS).Diagnosis can be pursued with molecular testing and endoscopic sampling.Early identification of these autosomal dominant pathologies allows to optimize malignancy surveillance,which helps reduce morbidity and mortality in both the affected patient population as well as at-risk family members.Endoscopic surveillance is an important pillar of prognosis and monitoring,with many patients eventually requiring surgical intervention.In this review,we discuss the diagnosis,surveillance,and management of HPS.