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.

Clinical and Molecular Characterization of SMAD4 Splicing Variants in Patients with Juvenile Polyposis Syndrome.

Juvenile polyposis syndrome (JPS) is an inherited autosomal dominant condition that predisposes to the development of juvenile polyps throughout the gastrointestinal (GI) tract, and it poses an increased risk of GI malignancy. Germline causative variants were identified in the SMAD4 gene in a subset (20%) of JPS cases. Most SMAD4 germline genetic variants published to date are missense, nonsense, and frameshift mutations. SMAD4 germline alterations predicted to result in aberrant splicing have rarely been reported. Here, we report two unrelated Italian families harboring two different SMAD4 intronic variants, c.424+5G>A and c.425-9A>G, which are clinically associated with colorectal cancer and/or juvenile GI polyps. In silico prediction analysis, in vitro minigene assays, and RT-PCR showed that the identified variants lead to aberrant SMAD4 splicing via the exonization of intronic nucleotides, resulting in a premature stop codon. This is expected to cause the production of a truncated protein. This study expands the landscape of SMAD4 germline genetic variants associated with GI polyposis and/or cancer. Moreover, it emphasizes the importance of the functional characterization of SMAD4 splicing variants through RNA analysis, which can provide new insights into genetic disease variant interpretation, enabling tailored genetic counseling, management, and surveillance of patients with GI polyposis and/or cancer.

Studying the Effect of the Host Genetic Background of Juvenile Polyposis Development Using Collaborative Cross and Smad4 Knock-Out Mouse Models.

Juvenile polyposis syndrome (JPS) is a rare autosomal dominant disorder characterized by multiple juvenile polyps in the gastrointestinal tract, often associated with mutations in genes such as Smad4 and BMPR1A. This study explores the impact of Smad4 knock-out on the development of intestinal polyps using collaborative cross (CC) mice, a genetically diverse model. Our results reveal a significant increase in intestinal polyps in Smad4 knock-out mice across the entire population, emphasizing the broad influence of Smad4 on polyposis. Sex-specific analyses demonstrate higher polyp counts in knock-out males and females compared to their WT counterparts, with distinct correlation patterns. Line-specific effects highlight the nuanced response to Smad4 knock-out, underscoring the importance of genetic variability. Multimorbidity heat maps offer insights into complex relationships between polyp counts, locations, and sizes. Heritability analysis reveals a significant genetic basis for polyp counts and sizes, while machine learning models, including k-nearest neighbors and linear regression, identify key predictors, enhancing our understanding of juvenile polyposis genetics. Overall, this study provides new information on understanding the intricate genetic interplay in the context of Smad4 knock-out, offering valuable insights that could inform the identification of potential therapeutic targets for juvenile polyposis and related diseases.

Juvenile polyposis syndrome in children: The impact of SMAD4 and BMPR1A mutations on clinical phenotype and polyp burden.

OBJECTIVE: A constitutional disease-causing variant (DCV) in the SMAD4 or BMPR1A genes is present in 40%-60% of patients with juvenile polyposis syndrome (JPS). The aim of this study was to characterize the clinical course and polyp burden in children with DCV-positive JPS compared to DCV-negative JPS. METHODS: Demographic, clinical, genetic, and endoscopic data of children with JPS were compiled from eight international centers in the ESPHGAN/NASPGHAN polyposis working group. RESULTS: A total of 124 children with JPS were included: 69 (56%) DCV-negative and 55 (44%) DCV-positive (53% SMAD4 and 47% BMPR1A) with a median (interquartile range) follow-up of 4 (2.8-6.4) years. DCV-positive children were diagnosed at an older age compared to DCV-negative children [12 (8-15.7) years vs. 5 (4-7) years, respectively, p < 0.001], had a higher frequency of family history of polyposis syndromes (50.9% vs. 1.4%, p < 0.001), experienced a greater frequency of extraintestinal manifestations (27.3% vs. 5.8%, p < 0.001), and underwent more gastrointestinal surgeries (16.4% vs. 1.4%, p = 0.002). The incidence rate ratio for the development of new colonic polyps was 6.15 (95% confidence interval 3.93-9.63, p < 0.001) in the DCV-positive group compared to the DCV-negative group, with an average of 12.2 versus 2 new polyps for every year of follow-up. There was no difference in the burden of polyps between patients with SMAD4 and BMPR1A mutations. CONCLUSIONS: This largest international cohort of pediatric JPS revealed that DCV-positive and DCV-negative children exhibit distinct clinical phenotype. These findings suggest a potential need of differentiated surveillance strategies based upon mutation status.

SMAD4 mosaicism in juvenile polyposis: Essential contribution of somatic analysis in diagnosis.

Juvenile polyposis syndrome (JPS) is a rare disease characterized by multiple hamartomatous polyps in the gastrointestinal tract, associated with pathogenic variants of BMPR1A and SMAD4. We present the description of SMAD4 mosaicism in a 30-year-old man who had caecum adenocarcinoma, 11 juvenile colon polyps and epistaxis since childhood. We conducted NGS polyposis and CRC panel analysis on DNA extracted from two polyps, revealing a likely pathogenic SMAD4 variant: NM_005359.5:c. 1600C>T, p.(Gln534*). This variant was then identified at a very low frequency on blood and normal colonic tissue, by targeted visualization of previously obtained NGS data. These findings support the presence of a likely pathogenic mosaic SMAD4 variant that aligns with the patient's phenotype. Given the relatively frequent occurrence of de novo SMAD4 mutations, somatic mosaicism could account for a significant proportion of sporadic JPS patients with unidentified pathogenic variants. This case underscores the diagnosis challenge of detecting mosaicism and emphasizes the importance of somatic analyses.

Phenotypic characterisation of SMAD4 variant carriers.

BACKGROUND: Both hereditary haemorrhagic telangiectasia (HHT) and juvenile polyposis syndrome (JPS) are known to be caused by SMAD4 pathogenic variants, with overlapping symptoms for both disorders in some patients. Additional connective tissue disorders have also been reported. Here, we describe carriers of SMAD4 variants followed in an HHT reference centre to further delineate the phenotype. METHODS: Observational study based on data collected from the Clinical Investigation for the Rendu-Osler Cohort database. RESULTS: Thirty-three participants from 15 families, out of 1114 patients with HHT, had an SMAD4 variant (3%).Regarding HHT, 26 out of 33 participants (88%) had a definite clinical diagnosis based on Curaçao criteria. Complication frequencies were as follows: epistaxis (n=27/33, 82%), cutaneous telangiectases (n=19/33, 58%), pulmonary arteriovenous malformations (n=17/32, 53%), hepatic arteriovenous malformations (AVMs) (n=7/18, 39%), digestive angiodysplasia (n=13/22, 59%). No cerebral AVMs were diagnosed.Regarding juvenile polyposis, 25 out of 31 participants (81%) met the criteria defined by Jass et al for juvenile polyposis syndrome. Seven patients (21%) had a prophylactic gastrectomy due to an extensive gastric polyposis incompatible with endoscopic follow-up, and four patients (13%) developed a digestive cancer.Regarding connective tissue disorders, 20 (61%) had at least one symptom, and 4 (15%) participants who underwent echocardiography had an aortic dilation. CONCLUSION: We describe a large cohort of SMAD4 variant carriers in the context of HHT. Digestive complications are frequent, early and diffuse, justifying endoscopy every 2 years. The HHT phenotype, associating pulmonary and hepatic AVMs, warrants systematic screening. Connective tissue disorders broaden the phenotype associated with SMAD4 gene variants and justify systematic cardiac ultrasound and skeletal complications screening.

Outcomes of patients with Juvenile Polyposis-Hereditary Haemorrhagic Telangiectasia caused by pathogenic SMAD4 variants in a pan-Scotland cohort.

Constitutional loss of SMAD4 function results in Juvenile Polyposis-Hereditary Haemorrhagic Telangiectasia Overlap Syndrome (JP-HHT). A retrospective multi-centre case-note review identified 28 patients with a pathogenic SMAD4 variant from 13 families across all Scottish Clinical Genetics Centres. This provided a complete clinical picture of the Scottish JP-HHT cohort. Colonic polyps were identified in 87% (23/28) and gastric polyps in 67% (12/18) of screened patients. Complication rates were high: 43% (10/23) of patients with polyps required a colectomy and 42% (5/12) required a gastrectomy. Colorectal cancer occurred in 25% (7/28) of patients, at a median age of 33 years. Pulmonary arteriovenous malformations were identified in 42% (8/19) of screened patients. 88% (23/26) and 81% (17/21) of patients exhibited JP and HHT features respectively, with 70% (14/20) demonstrating features of both conditions. We have shown that individuals with a pathogenic SMAD4 variant are all at high risk of both gastrointestinal neoplasia and HHT-related vascular complications, requiring a comprehensive screening programme.

Cronkhite‒Canada syndrome as inflammatory hamartomatous polyposis: new evidence from whole transcriptome sequencing of colonic polyps.

BACKGROUND: Cronkhite-Canada syndrome (CCS) is a rare, nonhereditary disease characterized by diffuse gastrointestinal polyposis and ectodermal abnormalities. Although it has been proposed to be a chronic inflammatory condition, direct evidence of its pathogenesis is lacking. This study aims to investigate the pathophysiology of CCS by analyzing transcriptomic changes in the colonic microenvironment. METHODS: Next-generation sequencing-based genome-wide transcriptional profiling was performed on colonic hamartomatous polyps from four CCS patients and normal colonic mucosa from four healthy volunteers. Analyses of differential expression and multiple enrichment analyses were conducted from the molecular level to the cellular level. Quantitative real-time PCR (qRT-PCR) was carried out to validate the sequencing accuracy in samples from six CCS patients and six healthy volunteers. RESULTS: A total of 543 differentially expressed genes were identified, including an abundance of CC- and CXC-chemokines. Innate immune response-related pathways and processes, such as leukocyte chemotaxis, cytokine production, IL-17, TNF, IL-1 and NF-kB signaling pathways, were prominently enhanced in CCS colonic polyps. Upregulation of wound healing, epithelial-mesenchymal transition, Wnt, and PI3K-Akt signaling pathways were also observed. Enrichment analyses at different levels identified extracellular structure disorganization, dysfunction of the gut mucosal barrier, and increased angiogenesis. Validation by qRT-PCR confirmed increased expression of the LCN2, IL1B, CXCL1, and CXCL3 genes in CCS colonic polyps. CONCLUSIONS: This case-control whole transcriptome analysis of active CCS colonic hamartomatous polyps revealed intricate molecular pathways, emphasizing the role of the innate immune response, extracellular matrix disorganization, inflammatory cell infiltration, increased angiogenesis, and potential epithelial to mesenchymal transition. These findings supports CCS as a chronic inflammatory condition and sheds light on potential therapeutic targets, paving the way for more effective and personalized management of CCS in the future.

Human intestinal organoids from Cronkhite-Canada syndrome patients reveal link between serotonin and proliferation.

Cronkhite-Canada Syndrome (CCS) is a rare, noninherited polyposis syndrome affecting 1 in every million individuals. Despite over 50 years of CCS cases, the etiopathogenesis and optimal treatment for CCS remains unknown due to the rarity of the disease and lack of model systems. To better understand the etiology of CCS, we generated human intestinal organoids (HIOs) from intestinal stem cells isolated from 2 patients. We discovered that CCS HIOs are highly proliferative and have increased numbers of enteroendocrine cells producing serotonin (also known as 5-hydroxytryptamine or 5HT). These features were also confirmed in patient tissue biopsies. Recombinant 5HT increased proliferation of non-CCS donor HIOs and inhibition of 5HT production in the CCS HIOs resulted in decreased proliferation, suggesting a link between local epithelial 5HT production and control of epithelial stem cell proliferation. This link was confirmed in genetically engineered HIOs with an increased number of enteroendocrine cells. This work provides a new mechanism to explain the pathogenesis of CCS and illustrates the important contribution of HIO cultures to understanding disease etiology and in the identification of novel therapies. Our work demonstrates the principle of using organoids for personalized medicine and sheds light on how intestinal hormones can play a role in intestinal epithelial proliferation.

Whole genome sequencing and disease pattern in patients with juvenile polyposis syndrome: a nationwide study.

Juvenile polyposis syndrome (JPS) is a hereditary hamartomatous polyposis syndrome characterized by gastrointestinal juvenile polyps and increased risk of gastrointestinal cancer. Germline pathogenic variants are detected in SMAD4 or BMPR1A, however in a significant number of patients with JPS, the etiology is unknown. From Danish registers, and genetic department and laboratories, we identified all patients in Denmark with a clinical diagnosis of JPS and/or a pathogenic variant in BMPR1A or SMAD4. In patients where no variant had been detected, we performed genetic analysis, including whole genome sequencing. We collected clinical information on all patients to investigate the phenotypic spectrum. Sixty-six patients (mean age 40 years) were included of whom the pathogenic variant was unknown in seven patients. We detected a pathogenic variant in SMAD4 or PTEN in additional three patients and thus ≈ 95% of patients had a pathogenic germline variant. Endoscopic information was available in fifty-two patients (79%) and of these 31 (60%) fulfilled the clinical criteria of JPS. In 41 patients (79%), other types of polyps than juvenile had been removed. Our results suggest that almost all patients with a clinical diagnosis of JPS has a pathogenic variant in mainly BMPR1A, SMAD4, and more rarely PTEN. However, not all patients with a pathogenic variant fulfil the clinical criteria of JPS. We also demonstrated a wide clinical spectrum, and that the histopathology of removed polyps varied.

Gastrointestinal Bleeding in the Setting of Juvenile Polyposis Syndrome Due to SMAD4 Mutation.

A 27-year-old female presented at 13 weeks' gestation with epigastric pain and anemia requiring blood and iron transfusions but no family history of gastrointestinal malignancy. Upper endoscopy revealed a giant circumferential polyp and associated hyperplastic-appearing polyps in the proximal stomach. Biopsies revealed hyperplasia with lamina propria eosinophils. She was supported with intermittent transfusions until labor was induced at 34 weeks' gestation. Total gastrectomy was performed at seven weeks post-partum. Final pathology revealed multiple hamartomatous polyps without malignancy. Her anemia resolved postoperatively. Genetic testing revealed mutation of the SMAD4 gene and Juvenile Polyposis Syndrome. JPS is caused by germline mutations in the SMAD4 or BMPR1A genes and is characterized by hamartomatous polyps in the gastrointestinal tract. While most polyps are benign, malignant transformation can occur. One should have low threshold to send patients for genetic screening when multiple polyps are found in a young patient, even without family history.

Clinical and functional characterisation of the SMAD4 germline variant c.1035C > A in a family with juvenile polyposis syndrome by whole-exome sequencing.

Juvenile polyposis syndrome (JPS) is a rare autosomal dominant inherited disease characterised by multiple juvenile polyps. Genes with JPS-associated mutations and their correlation with the phenotype are currently unknown. Gastrointestinal endoscopy results of a 31-year-old female patient showed multiple polyps in the digestive tract, and the presence of juvenile polyps was confirmed by pathological examination. During follow-up, the patient underwent total gastrectomy and polypectomy several times. Five members of this family were diagnosed with JPS, of which two died and three survived. Full exon gene sequencing of eight members of this family revealed a SMAD4 (NM-005359.3) c.1035C > A (p.Cys345*) mutation. This mutation leads to premature codon termination, causing protein truncation. SMAD4 is a pathogenic gene associated with JPS. This is the first report of an association between the c.1035C > A mutation and JPS pathogenesis. Detection of JPS-related mutations in family members with a genetic predisposition for JPS is very important for genetic counselling, surgical intervention, long-term monitoring and follow-up, and drug treatment.

Occurrence of gastric cancer in patients with juvenile polyposis syndrome: a systematic review and meta-analysis.

BACKGROUND AND AIMS: The true rate of gastric cancer (GC) in juvenile polyposis syndrome (JPS) is unknown because of its rarity and ascertainment bias in published literature. To better assess this, we conducted a systematic review and meta-analysis. METHODS: MEDLINE, Embase, and Scopus databases were searched for the key words juvenile polyposis syndrome, juvenile polyps, stomach cancer, GC, SMAD4, BMPR1A, hamartomatous polyposis syndrome, hamartomas, and hereditary cancers for studies reporting upper GI manifestations in JPS. The primary outcome was the reported occurrence of GC in JPS. We then compared GC occurrence based on the presence or absence of pathogenic germline variants (PGVs) and in untested patients. RESULTS: Eleven studies including 637 patients were included. The pooled occurrence of GC was 3.5% (95% confidence interval [CI], 1.8-5.2; I2 = 12.3%) at a median age of 42.5 years (range, 15-57.6). The pooled occurrence of GC in patients with SMAD4 PGV was 10.1% (95% CI, 3.2-16.8%; I2 = 54.7%). GC was reported in only 1 BMPR1A PGV carrier and was not reported in patients without an identifiable PGV. In patients with prior germline testing, the risk of GC was higher in SMAD4 PGV carriers (odds ratio, 11.6; 95% CI, 4.6-29.4; I2 = 18.3%) compared with patients without SMAD4 PGV. In JPS patients with unknown status of germline testing, pooled occurrence of GC was 7.5% (95% CI, 0-15.5). There was an overall moderate risk of bias in the studies. CONCLUSIONS: GC is highest in SMAD4-associated JPS and was not reported in patients without identifiable PGVs. The value of GC surveillance in BMPR1A PGV carriers and JPS patients without an identifiable PGV is questionable. Germline testing should be performed in all JPS patients to inform GC risk discussion and utility of surveillance.

A novel germline SMAD4 variant detected in a Japanese family with juvenile polyposis syndrome and hereditary hemorrhagic telangiectasia.

Juvenile polyposis syndrome (JPS) is an autosomal dominant, inherited disorder caused by pathogenic germline variants of mainly SMAD4 or BMPR1A genes. Some patients with JPS, especially with SMAD4 variants, also develop hereditary, hemorrhagic telangiectasia (HHT). HHT is also an autosomal dominant inherited disorder. Herein, we identified a novel germline pathogenic variant of the SMAD4 in a Japanese family with JPS and HHT. A six-base pair deletion in the SMAD4 gene (NM_005359.6:c.1495_1500delTGCATA) was identified in the patients. Two amino acids are deleted from SMAD4 protein (p.Cys499_Ile500del), which are located in MSH2 domain essential for the binding with SMAD3. This is a novel variant that has not been registered in any database surveyed. Amino acid structural analysis predicted significant changes in the secondary and three-dimensional structures in the vicinity of the two amino acids' deletion. The variant is classified as 'Likely Pathogenic' according to the American College of Medical Genetics and Genomics guidelines.

Whole Genome Sequencing Applied in Familial Hamartomatous Polyposis Identifies Novel Structural Variations.

Hamartomatous polyposis syndromes (HPS) are rare cancer-predisposing disorders including Juvenile polyposis (JPS), Peutz-Jeghers (PJS) and PTEN hamartomatous syndromes (PHS). Penetrant mutations in corresponding genes (SMAD4, BMPR1A, STK11, PTEN and AKT1), are usually diagnosed via a next-generation-sequencing gene panel (NGS-GP) for tailored surveillance and preimplantation testing for monogenic disorders (PGT-M). Five probands with HPS phenotype, with no genetic diagnosis per genetic workup, underwent whole-genome sequencing (WGS) that identified structural genetic alterations: two novel inversions in BMPRA1 and STK11, two BMPR1A-deletions, known as founders among Bukharan Jews, and BMPR1A microdeletion. BMPR1A inversion was validated by "junction fragment" amplification and direct testing. PGT-M was performed via multiplex-PCR and enabled successful birth of a non-carrier baby. WGS may be considered for HPS patients with no NGS-GP findings to exclude structural alterations.

Juvenile polyposis syndrome: An overview.

Juvenile polyposis syndrome (JPS) is a rare precancerous condition that confers an increased risk of developing gastrointestinal cancers. The inheritance pattern is autosomal dominant. JPS should be clinically suspected when the other hamartomatous polyposis syndromes are excluded (i.e., Peutz- Jeghers and Cowden), in presence of numerous juvenile polyps in the colorectum or in other GI locations. Among the syndromic features, JPS can present with concomitant extra-intestinal manifestations, above all cutaneous manifestations such as telangiectasia, pigmented nevi, and skeletal stigmata. Pathogenic germline variants of either BMPR1A or SMAD4 cause the syndrome. In JPS a cumulative risk of CRC of 39-68% has been estimated. The oncological risk justifies and imposes prevention strategies that aim at the cancer risk reduction through endoscopic screening, as recommended by international scientific societies. The aim of this review is to summarize clinical and genetic features of JPS and to elucidate the steps of the clinical management from diagnosis to surveillance.

Juvenile polyposis: Focus on less described manifestations.

Juvenile polyposis represents an heterogeneous disease as different genetic dominant backgrounds have been evidenced leading to different clinical presentations. It is associated in some patients with a different syndrome, Hereditary Hemorragic Telangiectasia, justifying a complementary and different management. Recent international recommendations help in managing this very rare disease, and this management should probably be restricted to expert centers able to take care of the multiple manifestations and risks of these patients and families. This paper will focus on the poorly known and evaluated aspects of juvenile polyposis, excluding the colonic involvement and epidemiology that are addressed in a different article of this issue.

The genomic landscape of Cronkhite-Canada syndrome: Possible clues for pathogenesis.

OBJECTIVES: Cronkhite-Canada syndrome (CCS) is a rare hamartomatous polyposis syndrome with a proposed association with chronic autoimmune inflammation. To date, genetic background of patients with CCS remains less investigated. In this study we aimed to explore the genomic landscape of CCS. METHODS: Whole exome sequencing was performed on peripheral blood samples extracted from 18 patients with CCS. Potential function-impacting germline variants were filtered by R software. Through systematic data analysis, a number of genetic variants were identified. Enrichment analysis was performed using the R package ClusterProfiler. RESULTS: Overall, 3960 low-frequency (<0.05 or not reported in the Exome Aggregation Consortium East Asian, 1000 Genomes, or ESP6500 database) potentially function-impacting germline variants were identified, with 18 genes (FDFT1, LOC400863, MUC3A, MUC4, ZNF806, GXYLT1, MUC6, PABPC3, PSPH, ZFPM1, CIC, LOC283710, ARSD, GOLGA6L2, LOC388282, SLC25A5, TMEM247, WDR89) involved over half the patients. Functional enrichment of these genes revealed several biological processes in relation to innate immune responses and glycosylation. Only one likely pathogenic germline variant of an hamartomatous polyposis syndrome-associated gene, PTCH1, was detected in one patient. CONCLUSIONS: CCS has genomic alteration patterns completely distinct from those of traditional hamartomatous polyposis syndrome. The germline mutation landscape indicates potential roles of innate immune responses and glycosylation in the pathogenesis of CCS.

FOCAD Indel in a Family With Juvenile Polyposis Syndrome.

Juvenile polyposis syndrome (JPS) is a childhood polyposis syndrome with up to a 50% lifetime risk of gastrointestinal cancer. Germline pathogenic variants in BMPR1A and SMAD4 are responsible for around 40% of cases of JPS, but for the majority of individuals, the underlying genetic cause is unknown. We identified a family for which polyposis spanned four generations, and the proband had a clinical diagnosis of JPS. Next-generation sequencing was conducted, followed by Sanger sequencing confirmation. We identified an internal deletion of the FOCAD gene in all family members tested that altered the reading frame and is predicted to be pathogenic. We conclude that inactivation of the FOCAD gene is likely to cause JPS in this family.