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

Peutz-Jeghers syndrome without STK11 mutation may correlate with less severe clinical manifestations in Chinese patients

BACKGROUND

Peutz-Jeghers syndrome (PJS) is an autosomal dominant genetic disease with skin mucosal pigment spots and gastrointestinal (GI) multiple hamartoma polyps as clinical characteristics. At present, it is considered that the germline mutation of STK11 gene is the genetic cause of PJS. However, not all PJS patients can be detected STK11 germline mutations. The specific clinical characteristics of these PJS patients without STK11 mutation is an interesting clinical question. Or, like wild type GI stromal tumor, whether these PJS without STK11 mutation are also called PJS is worth discussing. Therefore, we designed the study to understand the clinical characteristics of these PJS patients without STK11 mutation.

AIM

To investigates whether PJS patients with known STK11 mutations have a more severe spectrum of clinical phenotypes compared to those without.

METHODS

A total of 92 patients with PJS admitted to the Air Force Medical Center from 2010 to 2022 were randomly selected for study. Genomic DNA samples were extracted from peripheral blood samples, and pathogenic germline mutations of STK11 were detected by high-throughput next-generation gene sequencing. Clinical-pathologic manifestations of patients with and without STK11/LKB1 mutations were compared.

RESULTS

STK11 germline mutations were observed in 73 patients with PJS. Among 19 patients with no detectable STK11 mutations, six had no pathogenic germline mutations of other genes, while 13 had other genetic mutations. Compared with PJS patients with STK11 mutations, those without tended to be older at the age of initial treatment, age of first intussusception and age of initial surgery. They also had a lower number of total hospitalizations relating to intussusception or intestinal obstruction, and a lower load of small intestine polyps.

CONCLUSION

PJS patients without STK11 mutations might have less severe clinical-pathologic manifestations than those with.

Strong Hereditary Predispositions to Colorectal Cancer

Cancer is one of the most common causes of death worldwide. A strong predisposition to cancer is generally only observed in colorectal cancer (5% of cases) and breast cancer (2% of cases). Colorectal cancer is the most common cancer with a strong genetic predisposition, but it includes dozens of various syndromes. This group includes familial adenomatous polyposis, attenuated familial adenomatous polyposis, MUTYH-associated polyposis, NTHL1-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis syndrome, Cowden syndrome, Lynch syndrome, and Muir-Torre syndrome. The common symptom of all these diseases is a very high risk of colorectal cancer, but depending on the condition, their course is different in terms of age and range of cancer occurrence. The rate of cancer development is determined by its conditioning genes, too. Hereditary predispositions to cancer of the intestine are a group of symptoms of heterogeneous diseases, and their proper diagnosis is crucial for the appropriate management of patients and their successful treatment. Mutations of specific genes cause strong colorectal cancer predispositions. Identifying mutations of predisposing genes will support proper diagnosis and application of appropriate screening programs to avoid malignant neoplasm.

Small Bowel Epithelial Precursor Lesions: A Focus on Molecular Alterations

The wider use of gastrointestinal endoscopic procedures has led to an increased detection of small intestinal preneoplastic and neoplastic epithelial lesions, most of which are identified in the duodenum and ampullary region. Like their malignant counterparts, small intestinal glandular precursor lesions, which include adenomas and hamartomas, may arise sporadically or be associated with hereditary tumor syndromes, such as familial adenomatous polyposis, MUTYH-associated polyposis, Lynch syndrome, Peutz-Jeghers syndrome, juvenile polyposis syndrome, and Cowden syndrome. In addition, dysplastic, preinvasive lesions have been observed adjacent to small bowel adenocarcinomas complicating immune-related disorders, such as celiac or Crohn’s disease. Adenomatous lesions may exhibit an intestinal-type, gastric-type, or, very rarely, serrated differentiation, related to different molecular pathogenetic mechanisms. Finally, in the background of multiple endocrine neoplasia 1 syndrome, precursor neuroendocrine growths have been described. In this review we offer a comprehensive description on the histo-molecular features of the main histotypes of small bowel epithelial precursors lesions, including: (i) sporadic adenomas (intestinal-type and gastric-type; non-ampullary and ampullary); (ii) syndromic adenomas; (iii) small bowel dysplasia in celiac and Crohn’s disease; (iv) serrated lesions; (v) hamartomatous lesions; and (vi) neuroendocrine precursor lesions.

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.

Identification of SNPs and InDels associated with berry size in table grapes integrating genetic and transcriptomic approaches

BACKGROUND

Berry size is considered as one of the main selection criteria in table grapes breeding programs, due to the consumer preferences. However, berry size is a complex quantitive trait under polygenic control, and its genetic determination of berry weight is not yet fully understood. The aim of this work was to perform marker discovery using a transcriptomic approach, in order to identify and characterize SNP and InDel markers associated with berry size in table grapes. We used an integrative analysis based on RNA-Seq, SNP/InDel search and validation on table grape segregants and varieties with different genetic backgrounds.

RESULTS

Thirty SNPs and eight InDels were identified using a transcriptomic approach (RNA-Seq). These markers were selected from SNP/InDel found among segregants from a Ruby x Sultanina population with contrasting phenotypes for berry size. The set of 38 SNP and InDel markers was distributed in eight chromosomes. Genotype-phenotype association analyses were performed using a set of 13 RxS segregants and 41 table grapes varieties with different genetic backgrounds during three seasons. The results showed several degrees of association of these markers with berry size (10.2 to 30.7%) as other berry-related traits such as length and width. The co-localization of SNP and /or InDel markers and previously reported QTLs and candidate genes associated with berry size were analysed.

CONCLUSIONS

We identified a set of informative and transferable SNP and InDel markers associated with berry size. Our results suggest the suitability of SNPs and InDels as candidate markers for berry weight in seedless table grape breeding. The identification of genomic regions associated with berry weight in chromosomes 8, 15 and 17 was achieved with supporting evidence derived from a transcriptome experiment focused on SNP/InDel search, as well as from a QTL-linkage mapping approach. New regions possibly associated with berry weight in chromosomes 3, 6, 9 and 14 were identified.

Register and clinical follow-up of patients with Peutz-Jeghers syndrome in Valencia

INTRODUCTION AND OBJECTIVES

Peutz-Jeghers syndrome is a rare autosomal dominant inherited disease caused by a germline mutation of the STK11/LKB1 gene, located on chromosome 19p13.3. It is characterized by mucocutaneous hyperpigmentation, hamartomatous polyposis, and predisposition to cancer. The aim of the present study was to identify and register patients with Peutz-Jeghers syndrome, describe the disease, and estimate its prevalence in Valencia (Spain).

MATERIALS AND METHODS

A print-out of the clinical histories from 10 hospitals was obtained utilizing the ICD-9 code 759.6 from the Minimum Basic Data Set of Hospital Admissions of the Spanish Ministry of Health and Consumer Affairs.

RESULTS

From a total of 405 clinical histories found, 15 (9 males and 6 females) fit the diagnostic criteria of Peutz-Jeghers syndrome. Mean age at diagnosis was 13.8 years and mean age at death was 54.2 years. Four males died, all from cancer. The estimated disease prevalence was 0.4/100,000 inhabitants. All the patients presented with anemia and polyps in the small bowel (80% in the duodenum, 66.7% in the ileum, and 40% in the jejunum), 93.3% underwent urgent surgical intervention and presented with intestinal invagination, and 40% of the patients developed cancer at a mean age of 48.5 years.

CONCLUSION

The present study is the first register of patients with Peutz-Jeghers syndrome in Valencia, Spain. The ICD-9 code is nonspecific for rare diseases. The duodenum was the most frequent location for polyps and the majority of cases presented with intestinal invagination, bowel obstruction, and urgent surgical intervention. A large percentage of patients presented with cancer. It would be of interest to review and evaluate the existing surveillance protocols in the Valencian Community.

First report of somatic mosaicism for mutations in STK11 in four patients with Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is an autosomal dominant cancer predisposition syndrome characterised by gastrointestinal polyposis and mucocutaneous pigmentation. Mutations in STK11, a serine-threonine protein kinase, have been associated with PJS in up to 100 % of published series. The hypothesis that a further genetic locus for PJS exists is controversial. No mutations in any other genes have been described in association with PJS. To date, no instances of somatic mosaicism for STK11 have been described. DNA extracted from peripheral lymphocytes and buccal cells was screened by sequence analysis for mutations in STK11. Dosage analysis was undertaken by multiplex ligation-dependent probe amplification (MLPA). Four patients have been shown to have mosaicism in STK11: two had mosaic deletions of specific exons (2-3 and 3-10) of the STK11 gene; one had a mosaic nonsense mutation in exon 5; and one had a mosaic frameshift mutation in exon 8. This report details the first four reported cases of somatic mosaicism for STK11 associated with PJS. This shows that techniques in addition to direct sequencing such as MLPA must be used to assess for large scale genomic deletions in patients meeting clinical diagnostic criteria for PJS. This also adds further weight to the hypothesis of a single genetic locus for PJS.

Specific Alu elements involved in a significant percentage of copy number variations of the STK11 gene in patients with Peutz-Jeghers syndrome

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. PJS is preconditioned by the manifestation of mutations in the STK11 gene. The majority of detected STK11 changes are small scale mutations, however recent studies showed the significant contribution of medium-sized changes commonly known as copy number variations (CNVs). Here we present a novel 7001 bps deletion of STK11 gene fragment, in which we identified the presence of breakpoints (BPs) within the Alu elements. Comparative meta-analysis with the 80 other CNV cases from 12 publications describing STK11 mutations in patients with PJS revealed the participation of specific Alu elements in all deletions of exons 2–3 so far described. Moreover, we have shown their involvement in the two other CNVs, deletion of exon 2 and deletion of exon 1–3 respectively. Deletion of exons 2–3 of the STK11 gene may prove to be the most recurrent large rearrangement causing PJS. In addition, the sequences present in its BPs may be involved in a formation of a significant percentage of the remaining gene CNVs. This gives a new insight into the conditioning of this rare disease and enables improvements in PJS genetic diagnostics.

Peutz-Jeghers Syndrome With Diffuse Gastrointestinal Polyposis: Three Cases in a Family With Different Manifestations and No Evidence of Malignancy During 14 Years Follow Up

Introduction:

Peutz-Jeghers syndrome (PJS) is a rare disorder characterized by mucocutaneous perioral pigmentation, gastrointestinal hamartomatous polyposis, and an increased risk of malignancy. Families with PJS may show a variable spectrum of manifestations in spite of their consecutive generations. A probable explanation is novel mutations in contributing genes.

Case Presentation:

This report describes 3 cases of a family. Two daughters presented the classic PJS, while their father only manifested mucocutaneous perioral pigmentation. The junior daughter was underwent 3 and the eldest daughter 2 laparotomies for intussusception. The patients were visited annually and their medical findings were recorded during a follow-up period of 14 years. They were periodically examined in our hospital and despite conveying diffuse polyposis from the esophagus throughout the rectum in these three cases, even a simple hyperplasia was not found in obtained specimens.

Conclusions:

The patients with diffuse PJS may be asymptomatic and without gastrointestinal or extragastrointestinal malignancies.

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.