Truncating mutations in Peutz-Jeghers syndrome are associated with more polyps, surgical interventions and cancers

Genetic variation at a splicing branch point in intron 7 of STK11: a rare variant decreasing its expression in a Chinese family with Peutz-Jeghers syndrome

BACKGROUND

Peutz-Jeghers syndrome (PJS), a rare dominantly inherited disease, is primarily characterized by hamartomatous polyps and melanotic macules as well as by an increased risk of cancer. The current study aimed to identify the pathogenic gene and pathogenic mechanism of a proband with PJS, thereby offering precise prevention and treatment strategies for PJS.

METHODS

A detailed clinical examination was performed of the proband diagnosed with PJS and her family members. In addition, peripheral venous blood was collected from the family members to extract genomic DNA. The pathogenic genes of the proband were identified using whole-exome sequencing, and the candidate pathogenic variants were verified via Sanger sequencing. Meanwhile, co-segregation tests were performed among six family members. Finally, reverse transcription-polymerase chain reaction (RT-PCR) was performed to assess transcript variants in the peripheral blood cells of patients and non-related healthy controls.

RESULTS

Genetic testing revealed a rare splicing variant c.921-1G > C in STK11 in the proband and in her sister and nephew, and the variant co-segregated among the affected family members and nonrelated healthy controls. The proband phenotypically presented with a rare gastric-type adenocarcinoma of the cervix. RT-PCR revealed that the STK11 c.921-1G > C variant could produce two transcripts. Of note, 40 base pairs were deleted in the aberrant transcript between exons 3 and 4, resulting in a frameshift variant and premature termination of the amino acid in exon 6 and ultimately leading to the loss of its functional domain in the STK11 protein. Finally, RT-PCR showed that compared with healthy controls, STK11 mRNA expression level was < 50% in patients.

CONCLUSION

The present study results indicated that the rare splicing variant c.921-1G > C in intron 7 of STK11 may be a pathogenic variant in patients with PJS. However, this variant (in intron 7) may not produce abnormal transcripts (deletion of 40 base pairs between exons 3 and 4), and PJS may be attributed to the decrease in STK11 expression. Therefore, this study emphasized the importance of genetic counseling, pre-symptomatic monitoring, and early complication management in PJS.

The course and clinical manifestations of Peutz–Jeghers syndrome in the Russian population

Background. PeutzJeghers syndrome (PJS) is a rare hereditary syndrome characterized by the growth of hamartomatous polyps in the gastrointestinal tract, perioral pigmentation and an increased risk of malignant neoplasms. The syndrome is caused by a pathogenic variant in the STK11 gene. Aim. To assess the clinical picture and treatment of Russian patients with PJS. Materials and methods. A retrospective analysis of 30 patients from 25 families with an established diagnosis of PJS who were in the Ryzikh State Scientific Center for Coloproctology from 2011 to 2021 was carried out. All patients underwent instrumental examination, including esophagogastroduodenoscopy, colonoscopy, X-ray examination of the small intestine/CT-enterography, in the absence of invaginates video capsule endoscopy, as well as molecular genetic examination for the presence of pathogenic variants in the STK11 gene. All removed polyps were subjected to the histological examination. Results. The analysis of the clinical picture allowed us to establish the following data: the first complaints in patients were noted in childhood and adolescence, while the median age was 11 [7; 19] (0.524) years; pathogenic variants in the STK11 gene were identified in 26 (87%) cases, among which 10 were described for the first time; during the initial examination, polyps in the small intestine were detected in all 30 (100%) patients, in the stomach in 23/30 (77%) patients, and in the colon in 21/30 (70%); with an age, an increase in the number of polyps in all parts of the gastrointestinal tract was noted; before the diagnosis operations were performed urgently for intestinal obstruction; after the diagnosis of PJS, when polyps were detected in the gastrointestinal tract, endoscopic polypectomies were performed; if endoscopic removal of hamartomatous polyps was impossible, patients were operated as planned; malignant diseases of the predominantly reproductive system were detected in 8/30 (27%) patients. The median age of cancer detection was 52 [31; 52] (1759) years. Conclusion. Russian patients with PJS have population-specific features in the clinical picture of the course of the disease, which dictates the need to develop their own recommendations for monitoring and treatment of such patients.

STK11 Causative Variants and Copy Number Variations Identified in Thai Patients With Peutz-Jeghers Syndrome

Introduction Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disorder caused by germline mutations in the serine-threonine kinase 11 (STK11) tumor suppressor gene. This syndrome is characterized by hamartomatous gastrointestinal polyps, mucocutaneous melanin pigmentation, and a higher risk of developing various cancers. Methods We summarized the clinical and molecular characteristics of five unrelated Thai patients with PJS. Denaturing high-performance liquid chromatography (DHPLC) screening, coupled with direct DNA sequencing and multiplex ligation-dependent probe amplification (MLPA), were applied for the molecular analysis of STK11. Results A total of four STK11 pathogenic changeswere identified in the five PJS patients, including two frameshift variants (a novel c.199dup, p.Leu67ProfsTer96 and a known c.834_835del, p.Cys278TrpfsTer6) and two types of copy number variations (CNV), exon 1 deletion and exons 2-3 deletion. Among reported STK11 exonic deletions, exon 1 and exons 2-3 deletions were found to be the two most commonly deleted exons. Conclusion All identified STK11 mutations were null mutations that were associated with more severe PJS phenotypes and cancers. This study broadens the phenotypic and mutational spectrum of STK11 in PJS.

Identification of high-risk germline variants for the development of pancreatic cancer: Common characteristics and potential guidance to screening guidelines

Pancreatic cancer (PC) is a product of a variety of environmental and genetic factors. Recent work has highlighted the influence of hereditary syndromes on pancreatic cancer incidence. The purpose of this review is to identify the high-risk syndromes, common variants, and risks associated with PC. The study also elucidates common characteristics of patients with these mutations, which is used to recommend potential changes to current screening protocols for greater screening efficacy. We analyzed 8 syndromes and their respective variants: Hereditary Breast and Ovarian Cancer (BRCA1/2), Familial Atypical Multiple Mole Melanoma Syndrome (CDKN2A), Peutz-Jeghers Syndrome (STK11), Lynch Syndrome (PMS2, MLH1, MSH2, MSH6, EPCAM), Ataxia Telangiectasia (ATM), Li-Fraumeni Syndrome (TP53), Fanconi Anemia (PALB2), and Hereditary Pancreatitis (PRSS1, SPINK1, CFTR). Of 587 studies evaluated, 79 studies fit into our inclusion criteria. Information from each study was analyzed to draw conclusions on these variants as well as their association with pancreatic cancer. Information from this review is intended to improve precision medicine and improve criteria for screening.

The Management of Peutz-Jeghers Syndrome: European Hereditary Tumour Group (EHTG) Guideline

The scientific data to guide the management of Peutz–Jeghers syndrome (PJS) are sparse. The available evidence has been reviewed and discussed by diverse medical specialists in the field of PJS to update the previous guideline from 2010 and formulate a revised practical guideline for colleagues managing PJS patients. Methods: Literature searches were performed using MEDLINE, Embase, and Cochrane. Evidence levels and recommendation strengths were assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). A Delphi process was followed, with consensus being reached when ≥80% of the voting guideline committee members agreed. Recommendations and statements: The only recent guidelines available were for gastrointestinal and pancreatic management. These were reviewed and endorsed after confirming that no more recent relevant papers had been published. Literature searches were performed for additional questions and yielded a variable number of relevant papers depending on the subject addressed. Additional recommendations and statements were formulated. Conclusions: A decade on, the evidence base for recommendations remains poor, and collaborative studies are required to provide better data about this rare condition. Within these restrictions, multisystem, clinical management recommendations for PJS have been formulated.

Clinical and Genetic Analyses of 38 Chinese Patients with Peutz-Jeghers Syndrome

Background

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disease caused by a germline mutation in the STK11 gene. It is characterized by mucocutaneous pigmentation, gastrointestinal hamartomatous polyps, and cancer predisposition.

Aims

We aimed to summarize the main clinical and genetic features of Chinese PJS patients and assessed the genotype-phenotype correlations.

Methods

Thirty-eight patients clinically diagnosed with Peutz-Jeghers syndrome were included in this study from 2016 to 2019. Combined direct sequencing and multiplex ligation-dependent probe amplification tests were used to detect germline heterogeneous STK11 mutations. RNA sequencing was performed in polyps of PJS patients and control groups to evaluate the difference in expression of STK11. The genotype-phenotype correlations were calculated by Kaplan-Meier analyses.

Results

All 26 probands and 12 affected relatives had germline heterogeneous STK11 mutations among which 8 variants were novel. Individuals with missense mutations had their first surgery and other symptoms significantly later than individuals with null mutations.

Conclusion

This study expanded the spectrum of STK11 gene mutations and further elucidated individuals with null mutations of STK11 typically had an earlier onset of PJS symptoms and needed earlier management.

Pathogenesis, diagnosis, and treatment of Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS), an autosomal dominant inherited disease, is caused by germinal mutations of the STK11. It is characterized by gastrointestinal hamartomas, mucocutaneous pigmentation and increased cancer risk. Germline mutations in STK11 cause a harmful effect on cell apoptosis, G1 arrest, and cell polarization, which leads to polyp formation and cancer occurrence. Balloon-assisted enteroscopy is widely used in removal of PJS polyps in the small bowel and it is proved to be safe and effective. We suggest to screen polyps and cancer in PJS patients, which seems to benefit these patients in the long run.

Extremely young case of small bowel intussusception due to Peutz-Jeghers syndrome with nonsense mutation of STK11

Intussusception is a frequent and severe complication of Peutz-Jeghers syndrome (PJS). We herein present the case of a 3-year-old girl who experienced jejuno-jejunal intussusception due to PJS polyps. Despite no apparent family history of PJS, she had exhibited mucocutaneous pigmentation since infancy and recurrent abdominal pain and vomiting from 2 years of age. Segmental resection of the jejunum during emergency laparotomy for the intussusception revealed multiple hamartomatous polyps. Genetic analysis uncovered a germline nonsense mutation of c.247A>T in exon 1 of serine/threonine kinase 11 (STK11). Biannual follow-up surveillance for polyps by esophagogastroduodenoscopy, colonoscopy, and small bowel capsule endoscopy is ongoing. Reports describing the clinical and genetic features of extremely young PJS with intussusceptions are rare, although a literature review of STK11 germline mutations revealed several other pediatric cases of complicating intussusception at ≤ 8 years old. Considering the recent advances in surveillance and treatment options for the small bowel, earlier management of symptomatic children with PJS may be warranted to avoid surgical emergency.

An exploration of genotype-phenotype link between Peutz-Jeghers syndrome and STK11: a review

Peutz-Jeghers Syndrome (PJS) is an autosomal dominant hereditary polyposis syndrome. Clinical features include hamartomatous polyps, mucocutaneous pigmentation and an increased predisposition towards developing malignancy. Variants in STK11, a tumour suppressor gene, located on Chromosome 19, predispose to PJS. Peutz-Jeghers Syndrome is associated with increased rates of malignancy, particularly gastrointestinal. However, PJS is also associated with increased gynaecological, testicular and thyroid papillary malignancy. Truncating variants in STK11 are thought to predispose to a more severe phenotype. Phenotype severity is based on earlier onset of gastrointestinal pathology arising from the polyps, such as intussusception or earlier onset malignancy. Missense variants are generally considered less severe than truncating variants. There remain a large number of variants of undetermined significance. Studies have attempted to correlate the location of variants with impact on protein structure and overall severity of the PJS phenotype. The results from these cohort studies have consistently found a non-random distribution of variants. Nevertheless, a consensus on phenotype severity based on variant location is yet to be established. A centralised database that collates all known variants would facilitate the interpretation of these variants, best under the governance of an international disease-specific organisation (InSiGHT). In particular, it could help explore the significance of variants based on their type or location. Understanding the genotype-phenotype link between STK11 variants and PJS could allow more personalised care for PJS patients and their families via appropriate risk stratification and personalised and targeted cancer screening.

STK11 gene analysis reveals a significant number of splice mutations in Chinese PJS patients

BACKGROUND

The combination of direct sequencing and multiple ligation-dependent probe amplification (MLPA) has resulted in an 80% detection rate of serine/threonine kinase 11 (STK11) gene mutations in Peutz-Jeghers syndrome (PJS); however, this rate varies in different ethnicities.

AIMS

To test the efficacy of the combination in Chinese patients with PJS.

METHODS

PJS probands visiting our center during one year were enrolled. Sanger sequencing and MLPA were used to detect STK11 mutations. Associations between the occurrence of severe complications and risk factors were analyzed statistically.

RESULTS

We identified 47 PJS probands. Among them, 34 received an STK11 mutation test, revealing 23 point mutations and 2 exonic deletions. Nine of the mutations were splicing errors, reflecting a significantly higher proportion (p < 0.05). Laparotomy history existed for 33 of the probands, and seven families had a history of cancer. Statistical analysis revealed no associations between the occurrence of severe complications or cancers and risk factors.

CONCLUSION

The strategy achieved a high detection rate in Chinese people, validating its effectiveness. This cohort comprised a significantly higher proportion of splicing errors, reflecting the unique genetic characteristics Chinese people. No specific genotype-phenotype relationship was noted, while the wide usage of enteroscopy would benefit PJS surveillance.

A lesson from a reported pathogenic variant in Peutz-Jeghers syndrome: a case report

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disorder characterized by mucocutaneous hyperpigmentation, gastrointestinal (GI) hamartmatous polyps, and an increased risk of various malignancies. Pathogenic variants in the LKB1 tumor suppressor gene (also known as STK11) are the major cause of PJS. In this study, compound heterozygous variants of LKB1, c.890G > A/ c.1062C > G and del(exon1)/ c.1062C > G, were identified in two sporadic Chinese PJS cases respectively. Although all these three variants had been related to the autosomal dominant PJS in previous studies, all evidences collected in this study including de novo data, segregation data, population data, in-silico data, and functional data indicated that del(exon1) and c.890G > A are pathogenic in these two PJS families rather than c.1062C > G. This finding would contribute to genetic counseling for individuals carrying the variant c.1062C > G with or without PJS phenotypes. Moreover, this finding reminds genetic counselors that it is necessary to reevaluate the pathogenicity of reported variants in a known Mendelian disorder in order to avoid a misleading decision.

Paediatric ovarian tumours and their associated cancer susceptibility syndromes

Non-epithelial ovarian tumours are rare neoplasms that occasionally arise in childhood and adolescence. They can be associated with various cancer susceptibility syndromes. The morphological overlap seen across these tumours and their rarity can make the diagnosis challenging. In the case of an incorrect diagnosis, the underlying genetic susceptibility may be missed. In this review, we outline the genetic background of ovarian non-epithelial tumours arising in children, emphasizing the genes harbouring pathogenic germline variants associated with each tumour type. Specifically, juvenile granulosa cell tumours, Sertoli-Leydig cell tumours, sex cord tumours with annular tubules, Sertoli cell tumours, germ cell tumours and small cell carcinoma of the ovary of hypercalcaemic type are discussed in this review. For each tumour type, we detail the personal and family history features and the presenting characteristics of the ovarian tumour as well as the pathological features and molecular markers that point towards a cancer predisposition syndrome. Throughout, we stress the need for specialised pathological review in difficult cases.

Syndrome mit breitem Tumorspektrum

Die klinische Diagnose erblicher Tumorsyndrome ist ein wesentlicher Bestandteil der humangenetischen Beratung. Bei seltenen Syndromen, die mit einem breiten Spektrum an Tumoren und phänotypischen Überschneidungen einhergehen, ist dies nicht immer einfach. In diesem Artikel sollen deshalb die typischen und wegweisenden Merkmale der wichtigsten seltenen Tumordispositionssyndrome mit breitem Tumorspektrum herausgearbeitet werden. Hierzu gehören der Carney-Komplex, das Cowden-Syndrom, die juvenile Polyposis, das Li-Fraumeni-Syndrom und das Peutz-Jeghers-Syndrom. Darüber hinaus sind auch die derzeit empfohlenen Früherkennungsuntersuchungen dargestellt, die meist eine interdisziplinäre Betreuung der Patienten erforderlich machen.

Clinical manifestations and STK11 germline mutations in Taiwanese patients with Peutz-Jeghers syndrome

BACKGROUNDS

Clinical manifestations and molecular basis of Taiwanese patients with Peutz-Jeghers syndrome (PJS) were investigated to add the knowledge of phenotype and genotype of the disease.

METHODS

Based on the Pathology Data Bank and the Colorectal Cancer Register, we collected their clinical data. The entire coding sequence of the STK11 gene was amplified and analyzed by sequencing using the genomic DNA.

RESULTS

Fifteen patients diagnosed with PJS from 11 unrelated families were collected until 2015. The median age at the onset of symptoms was 19 years with intussusception as the most frequent presenting symptom. Ten patients developing 11 cancers at various anatomical sites, including two cases of sinonasal cancer, two lung cancers, two breast cancers, two rectal cancers, two gynecological cancers and one small bowel cancer. Five of the deceased patients had died of cancers. The median age of diagnosis of first cancer in the probands was 32 years. Seventy patients (7 of 10) diagnosed before age of 40. Mutations found in eight families included five novel mutations (exon 6, c.843 ins G; exon 8, c.2065 delete A; exon 8, c.G923A, nonsense; exon 6, c.748dupA; and mTOR c.5107dupA) and three previously reported mutations. The other three PJS families without detectable STK11 mutations did not develop malignancies so far.

CONCLUSION

This is the first comprehensive study of patients with Peutz-Jeghers syndrome in the Taiwanese. We have demonstrated that the phenotype of Peutz-Jeghers syndrome varies greatly among the patients. Patients with detectable STK11 mutations have very high risk of developing cancers.

Correlation between genotype and phenotype in three families with Peutz-Jeghers Syndrome

Peutz-Jeghers syndrome (PJS) is a hereditary disorder characterized by mucocutaneous pigmentations, gastrointestinal (GI) polyposis and an increased risk of certain malignancies. Little is known about the causative genes of PJS, or their association with the clinical phenotypes of PJS. The present study reports the results of clinical and genetic analysis of three Chinese families with PJS. In addition, the medical histories and clinical manifestations of these families were compared. DNA was collected from the blood samples of patients with PJS and controls. Serine/threonine kinase 11 (STK11), olfactory receptor family 4 subfamily C member 45 (OR4C45) and zonadhesin (ZAN) were amplified by polymerase chain reaction, and analyzed by sequencing and cloning. Two PJS-affected members of one family had a de novo single base deletion (NM_000455.4:c.842delC) in the STK11 gene, and their clinical presentations reflected the quantity of mutant STK11 copies in a dose-dependent manner. No pathogenic variants of OR4C45 or ZAN were found in the patients with PJS, although a new single nucleotide polymorphism (NM_003386.2:c.5768delG) of ZAN was identified. The results of the current study identified that a STK11 mutation dose-dependent genotype-phenotype relationship exists in patients with PJS. In addition, an early onset and high severity of oral pigmentations in PJS was indicative of serious GI phenotypes. These findings may aid the diagnosis and treatment of PJS.

Disease pattern in Danish patients with Peutz-Jeghers syndrome

PURPOSE

In this paper, we aimed to collect genetic and medical information on all Danish patients with Peutz-Jeghers syndrome (PJS), in order to contribute to the knowledge of phenotype and genotype. Peutz-Jeghers syndrome is a hereditary syndrome characterized by multiple hamartomatous polyps in the GI tract, mucocutaneous pigmentations, and an increased risk of cancer in the GI tract and at extraintestinal sites. Over 90 % of patients harbour a pathogenic mutation in STK11.

METHODS

Based on the Danish Pathology Data Bank, the Danish National Patient Register, as well as information from relevant departments at Danish hospitals, we identified patients and collected clinical and genetic information.

RESULTS

We identified 43 patients of which 14 were deceased. The prevalence was estimated to be ∼1 in 195,000 individuals. The median age at first symptom was 27.5 with invagination of the small bowel as the most frequent presenting symptom. We noted 18 occurrences of cancer at various anatomical sites, including a case of thyroid cancer and penile cancer. Eight of the deceased patients had died of cancer. Eighteen different mutations in STK11 had been detected in 28 patients.

CONCLUSION

This is the first comprehensive study of patients with Peutz-Jeghers syndrome in the Danish population identified from nationwide registers and databases. We have demonstrated that the expressivity of Peutz-Jeghers syndrome varies greatly among the patients, even within the same families, underlining the great phenotypic spectrum. Patients with PJS should be offered surveillance from childhood in order to prevent morbidity and reduce mortality.

Clinical features, endoscopic polypectomy and STK11 gene mutation in a nine-month-old Peutz-Jeghers syndrome Chinese infant

AIM: To investigate multiple polyps in a Chinese Peutz-Jeghers syndrome (PJS) infant.

METHODS: A nine-month-old PJS infant was admitted to our hospital for recurrent prolapsed rectal polyps for one month. The clinical characteristics, a colonoscopic image, the pathological characteristics of the polyps and X-ray images of the intestinal perforation were obtained. Serine threonine-protein kinase 11 (STK11) gene analysis was also performed using a DNA sample from this infant.

RESULTS: Here we describe the youngest known Chinese infant with PJS. Five polyps, including a giant polyp of approximately 4 cm × 2 cm in size, were removed from the infant’s intestine. Laparotomy was performed to repair a perforation caused by pneumoperitoneum. The pathological results showed that this child had PJS. Molecular analysis of the STK11 gene further revealed a novel frameshift mutation (c.64_65het_delAT) in exon 1 in this PJS infant.

CONCLUSION: The appropriate treatment method for multiple polyps in an infant must be carefully considered. Our results also show that the STK11 gene mutation is the primary cause of PJS.

Clinical characteristics and STK11 gene mutations in Chinese children with Peutz-Jeghers syndrome

Background

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disease characterized by gastrointestinal hamartomatous polyps and mucocutaneous melanin spots. Germline mutation of the serine/threonine kinase 11 (STK11) gene are responsible for PJS. In this study, we investigated the clinical characteristics and molecular basis of the disease in Chinese children with PJS.

Methods

Thirteen children diagnosed with PJS in our hospital were enrolled in this study from 2011 to 2015, and their clinical data on polyp characteristics, intussusceptions events, family histories, etc. were described. Genomic DNA was extracted from whole-blood samples from each subject, and the entire coding sequence of the STK11 gene was amplified by polymerase chain reaction and analyzed by direct sequencing.

Results

The median age at the onset of symptoms was 2 years and 4 months. To date, these children have undergone 40 endoscopy screenings, 17 laparotomies and 9 intussusceptions. Polyps were found in the stomach, duodenum, small bowel, colon and rectum, with large polyps found in 7 children. Mutations were found in eleven children, including seven novel mutations (c.481het_dupA, c.943_944het_delCCinsG, c.397het_delG, c.862 + 1G > G/A, c.348_349het_delGT, and c.803_804het_delGGinsC and c.121_139de l19insTT) and four previously reported mutations (c.658C > C/T, c.890G > G/A, c.1062 C > C/G, and c.290 + 1G > G/A). One PJS patient did not have any STK11 mutations.

Conclusions

The polyps caused significant clinical consequences in children with PJS, and mutations of the STK11 gene are generally the cause of PJS in Chinese children. This study expands the spectrum of known STK11 gene mutations.

Peutz-Jeghers syndrome: early clinical expression of a new STK11 gene variant

Genetic heterogeneity has been recognised in Peutz-Jeghers syndrome (PJS) (over 230 STK11 gene mutations reported). We report a rare PJS phenotype with early extensive gastrointestinal (GI) presentation and a new genetic variant. The case presented as haematochezia and mucocutaneous pigmentation (the patient was 3 years of age). Endoscopy showed several polyps throughout the stomach/colon (PJ-type hamartomas); the larger polyps were resected. Small bowel imaging detected multiple jejunum/ileum small polyps. During 8 years of follow-up of this asymptomatic patient, an increasing number of diffusely distributed polyps was observed and polypectomies were performed. Subsequently, the patient failed consultations; when the patient was 13 years of age, emergency surgery was required due to small bowel intussusception (ileal polyp). A STK11 gene study identified two missense variants in heterozygous (yet unknown significance but probably pathogenic): c.854T>A (exon 6) and c.446C>T* (exon 2) (*not previously reported). We report two STK11 gene variants (one not previously described) of yet undetermined causality in a paediatric patient presenting with extensive GI involvement at a very early age, with no family medical history. Structural and functional repercussion of the newly described variants should be further investigated.

STK11 gene mutations in patients with Peutz-Jeghers syndrome

AIM: To identify point mutations in the STK11 gene coding region in patients with Peutz-Jeghers syndrome (PJS).

METHODS: The sequences of the coding region of the STK11 gene in 36 PJS patients were analyzed using PCR and DNA sequencing and compared with the normal sequence of the STK11 gene.

RESULTS: Of the 36 patients with PJS, 22 showed STK11 gene mutations in the coding region, including 3 patients having the same mutation and 19 patients with a unique mutation site. The remaining 14 patients were not found to have mutations in the STK11 gene coding region. Of the 22 patients with STK11 gene mutations, 5 showed frame-shift mutations, of which 2 were included in SNP gene databases, and 17 showed missense mutations, of which 8 were changed to a termination codon and 4 were included in SNP gene databases. Among the gene mutations identified in our patients, 15 were not included in gene databases and were considered new mutations. The gene mutation rate was 62.5% in patients with a family history and 60.0% in sporadic cases (P > 0.05).

CONCLUSION: Mutations of the STK11 gene are a major cause of PJS. The newly found missense and frame-shift mutations may be associated with PJS.

Findings from the Peutz-Jeghers syndrome registry of uruguay

Background

Peutz-Jeghers syndrome (PJS) is characterized by intestinal polyposis, mucocutaneous pigmentation and an increased cancer risk, usually caused by mutations of the STK11 gene. This study collected epidemiological, clinical and genetic data from all Uruguayan PJS patients.

Methods

Clinical data were obtained from public and private medical centers and updated annually. Sequencing of the STK11 gene in one member of each family was performed.

Results and discussion

25 cases in 11 unrelated families were registered (15 males, 10 females). The average age of diagnosis and death was 18 and 41 years respectively. All patients had characteristic PJS pigmentation and gastrointestinal polyps. 72% required urgent surgery due to intestinal obstruction. 3 families had multiple cases of seizure disorder, representing 20% of cases. 28% developed cancer and two patients had more than one cancer. An STK11 mutation was found in 8 of the 9 families analyzed. A unique M136K missense mutation was noted in one family. Comparing annual live births and PJS birth records from 1970 to 2009 yielded an incidence of 1 in 155,000.

Conclusion

The Uruguayan Registry for Peutz-Jeghers patients showed a high chance of emergent surgery, epilepsy, cancer and shortened life expectancy. The M136K missense mutation is a newly reported STK 11 mutation.

Analysis of STK11 gene variant in five Chinese patients with Peutz-Jeghers syndrome

BACKGROUND

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disorder characterized by gastrointestinal hamartomatous polyps and mucocutaneous pigmentation. Germline mutation of a serine/threonine kinase 11(STK11) gene has been identified as a cause of PJS. In this study, we investigated the molecular basis of five Chinese PJS patients.

METHODS

Blood samples were collected from five unrelated Chinese PJS patients and their parents. The entire coding region of the STK11 gene was amplified by polymerase chain reaction and analyzed by direct sequencing.

RESULTS

Three different frameshift mutations (c.519insTGTG, c.792_793insT, and c.334_335insC), all of which would cause truncation of the gene product, were found in three patients. One missense mutation (p.Ser307Thr) and one 3bp deletion mutation (c.228-230del CGT) were identified in the remaining two patients. All of the five investigated patients carried de novo mutations.

CONCLUSIONS

The results support that mutation of the LKB1 gene is a cause of PJS, and expand the spectrum of the STK11 gene mutations.

Cancer risk associated with STK11/LKB1 germline mutations in Peutz-Jeghers syndrome patients: results of an Italian multicenter study

BACKGROUND

Germline mutations in the STK11/LKB1 gene cause Peutz-Jeghers syndrome, an autosomal-dominantly inherited condition characterized by mucocutaneous pigmentation, hamartomatous gastrointestinal polyposis, and an increased risk for various malignancies. We here report the results of the first Italian collaborative study on Peutz-Jeghers syndrome.

AIMS

To assess cancer risks in a large homogenous cohort of patients with Peutz-Jeghers syndrome, carrying, in large majority, an identified STK11/LKB1 mutation.

METHODS

One-hundred and nineteen patients with Peutz-Jeghers syndrome, ascertained in sixteen different Italian centres, were enrolled in a retrospective cohort study. Relative and cumulative cancer risks and genotype-phenotype correlations were evaluated.

RESULTS

36 malignant tumours were found in 31/119 (29 STK11/LKB1 mutation carriers) patients. The mean age at first cancer diagnosis was 41 years. The relative overall cancer risk was 15.1 with a significantly higher risk (p < 0.001) in females (22.0) than in males (8.6). Highly increased relative risks were present for gastrointestinal (126.2) and gynaecological cancers (27.7), in particular for pancreatic (139.7) and cervical cancer (55.6). The Kaplan-Meier estimates for overall cumulative cancer risks were 20%, 43%, 71%, and 89%, at age 40, 50, 60 and 65 years, respectively.

CONCLUSION

Peutz-Jeghers syndrome entails markedly elevated cancer risks, mainly for pancreatic and cervical cancers. This study provides a helpful reference for improving current surveillance protocols.

High Resolution Melting analysis as a rapid and efficient method of screening for small mutations in the STK11 gene in patients with Peutz-Jeghers syndrome

Background

Peutz-Jeghers syndrome (PJS) is a rare hereditary syndrome characterized by the occurrence of hamartomatous polyps in the gastrointestinal tract, mucocutaneous pigmentation and increased risk of cancer in multiple internal organs. Depending on the studied population, its incidence has been estimated to range from 1:200 000 even up to 1:50 000 births. Being an autosomal disease, PJS is caused in most cases by mutations in the STK11 gene.

Methods

The majority of causative DNA changes identified in patients with PJS are small mutations and, therefore, developing a method of their detection is a key aspect in the advancement of genetic diagnostics of PJS patients. We designed 13 pairs of primers, which amplify at the same temperature and enable examination of all coding exons of the STK11 gene by the HRM analysis.

Results

In our group of 41 families with PJS small mutations of the STK11 gene were detected in 22 families (54%). In the remaining cases all of the coding exons were sequenced. However, this has not allowed to detect any additional mutations.

Conclusions

The developed methodology is a rapid and cost-effective screening tool for small mutations in PJS patients and makes it possible to detect all the STK11 gene sequence changes occurring in this group.

Novel serine/threonine kinase 11 gene mutations in Peutz-Jeghers syndrome patients and endoscopic management

AIM: To explore mutations in serine/threonine kinase 11 (STK11) gene in Peutz-Jeghers syndrome (PJS) with gastrointestinal (GI) hamartomatous polyps.

METHODS: Six Japanese PJS patients in 3 families were enrolled in this study. Each of the cases had hamartomatous polyposis in the gastrointestinal tract, including the small intestine, along with mucocutaneous hyperpigmentation. Narrow-band imaging (NBI)-magnification endoscopy was employed to detect microvascular and microsurface irregularities in the GI lesions. NBI magnification findings could be classified into three groups (type A, type B, or type C). Endoscopic polypectomy was performed using double-balloon enteroscopy or colonoscopy. Genomic DNA was extracted from a whole blood sample from each subject. All of the coding exons of STK11 gene, its boundary regions, and the promoter region containing the polymorphic regions were amplified by polymerase chain reaction, and direct sequencing was performed to assess the germline mutations.

RESULTS: NBI-magnification endoscopic observation could detect the abnormalities in microvessels and microsurface structures of GI polyps. Overall, we found 5 cases of type A and one case without the examination for the gastric polyps, while there were 4 cases of type B and 2 case of type A for the colorectal polyps. Seventy-nine small-bowel and 115 colorectal polyps over 27 sessions for each were resected endoscopically without significant complications. The only delayed complication included the occurrence of bleeding in a case, and this was successfully managed with hemoclips. Resected polyps contained no malignant components. Based on mutation analysis, all 3 cases in Family I exhibited the +658C>T nonsense mutation in exon 5, which resulted in the production of a truncated protein (Q220X). In Family II, a case had -252C>A and -193C>A in the promoter region. In Family III, a case was found to have the +1062C>G (F342L) mutation in exon 8.

CONCLUSION: We found two novel mutations of STK11 in association with PJS. Endoscopic polypectomy of GI polyps in PJS patients appears to be useful to prevent emergency laparotomies and reduce the cancer risk.

Peutz-Jegher syndrome in childhood: need for updated recommendations?

BACKGROUND AND AIMS

We reviewed our institution's experience with Peutz-Jegher syndrome (PJS) in children to determine whether current recommendations on timing of screening and follow-up should be modified.

METHODS

We reviewed the charts of all of the children with a diagnosis of PJS at our institution from 2000 to 2011 abstracting data on intussusceptions events, polyp characteristics, Sertoli cell (SC) tumors, family history, imaging, and interventions.

RESULTS

Of 14 children identified, 10 were boys. Median age at first clinical evaluation was 4.5 years, and family history and/or mucocutaneous pigmentation were the 2 most common factors stimulating screening. Median age at first screening test was 5 years (range 1-16), and at first polyp identification, 5 years (range 1 to 18). There were 7 intussusception events in 5 children, with median age of 10 and range 5 to 16 for first event. Two boys had SC tumors at 8 and 11 years. Polyps were identified during initial screening in 9 of 14 patients. Polyps were found in the stomach or duodenum in 5 (36%), small bowel in 7, (50%) and colon in 3 (21%) children. Large polyps were identified in 9 children at median age of 7 years.

CONCLUSIONS

Polyps causing significant clinical consequences can occur frequently in children with PJS younger than 8 years. Revised guidelines should consider initial screening at age 4 to 5 with capsule endoscopy and upper and lower endoscopy as well as evaluation for SC tumors and re-evaluation whenever symptoms suggest polyp-associated complications.

The association of adrenocortical carcinoma and thyroid cancer in a child with Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is a rare, dominantly inherited disorder characterized by gastrointestinal hamartomatous polyps, mucocutaneous hyperpigmentation, and an increased risk of cancer. We present a 16-month-old child diagnosed with PJS, who had distinguishing features compared with the previously reported cases with respect to her clinical presentation, associated malignancies, and genetic analysis. To our knowledge, this is the first report of adrenocortical carcinoma in association with PJS, as well as the first instance of associated thyroid cancer in a child with PJS. We briefly review the relevant literature and highlight the recent progress achieved in the investigation of the syndrome.

Capsule endoscopy in small-bowel surveillance of patients with hereditary polyposis syndromes

PURPOSE

Familial adenomatous polyposis (FAP) and Peutz-Jeghers syndrome (PJS) are hereditary polyposis syndromes with a high risk for benign small-bowel polyps and cancer. The aim of this study was to assess the prevalence of small-bowel polyps beyond the duodenum in patients with FAP and PJS and to examine the clinical value and the optimal interval of capsule endoscopy (CE) for the surveillance of small-bowel polyps in patients with FAP.

METHODS

Between 2002 and 2009, standard gastroscopy, duodenoscopy, and CE were performed on 19 consecutive patients with hereditary polyposis syndromes (FAP n=15; PJS n=4). The number, size, and location of polyps detected by CE were assessed. Five FAP patients had repeated CEs in intervals of 2-7 years.

RESULTS

In 13 of the 15 (87%) FAP patients, small-bowel polyps were detected by CE ranging from estimated <5 mm to >10 mm in size. Thereof, in four patients, medium-sized (5-10 mm) or large-sized (>10 mm) polyps were seen-all of them located in the proximal jejunum. In three FAP patients with repeated CEs, the latest CE displayed medium- and large-sized polyps in the proximal jejunum, whereas previous CEs had detected only small-sized (<5 mm) polyps. In three of the four PJS patients, large-sized small-bowel polyps were visualized by CE which could then be removed by double-balloon enteroscopy (DBE) or surgical resection.

CONCLUSION

CE is an effective and safe method for small-bowel surveillance in FAP and PJS.

High cancer risk in Peutz-Jeghers syndrome: a systematic review and surveillance recommendations

OBJECTIVES

Peutz-Jeghers syndrome (PJS) is an autosomal dominant inherited disorder associated with increased cancer risk. Surveillance and patient management are, however, hampered by a wide range in cancer risk estimates. We therefore performed a systematic review to assess cancer risks in PJS patients and used these data to develop a surveillance recommendation.

METHODS

A systematic PubMed search was performed up to February 2009, and all original articles dealing with PJS patients with confirmed cancer diagnoses were included. Data involving cancer frequencies, mean ages at cancer diagnosis, relative risks (RRs), and cumulative risks were collected.

RESULTS

Twenty-one original articles, 20 cohort studies, and one meta-analysis fulfilled the inclusion criteria. The cohort studies showed some overlap in the patient population and included a total of 1,644 patients; 349 of them developed 384 malignancies at an average age of 42 years. The most common malignancy was colorectal cancer, followed by breast, small bowel, gastric, and pancreatic cancers. The reported lifetime risk for any cancer varied between 37 and 93%, with RRs ranging from 9.9 to 18 in comparison with the general population. Age-related cumulative risks were given for any cancer and gastrointestinal, gynecological, colorectal, pancreatic, and lung cancers.

CONCLUSIONS

PJS patients are markedly at risk for several malignancies, in particular gastrointestinal cancers and breast cancer. On the basis of these elevated risks, a surveillance recommendation is developed to detect malignancies in an early phase and to remove polyps that may be premalignant and may cause complications, so as to improve the outcome.