[Peutz-Jeghers syndrome, about 3 cases in siblings]

Le SPJ est une maladie rare de transmission autosomique dominante, défini par l’association d’une atteinte cutanée à type de lentiginose péri-orificielle d’une atteinte digestive, pulmonaire et des organes reproducteurs. Le gène de PJS a été localisé sur le chromosome 19p13.13. Les signes cutanés sont affichants et constituent un signe révélateur de la maladie, ils sont à type de lentigines, Ils siègent le plus souvent sur les lèvres, la muqueuse buccale. Les polypes digestifs constituent le deuxième signe cardinal de ce syndrome et ils peuvent révéler la maladie lorsqu’ils se manifestent d’emblée par leur complication telles les hémorragies digestives et les obstructions. Les personnes atteintes de SPJ courent un risque accru de cancers, le risque cumulatif de cancer est estimé à 93%, Les organes les plus fréquemment touchés sont le tractus gastro-intestinal (oesophage, estomac, intestin grêle, côlon, rectum et pancréas), le poumon, la prostate, le sein et les organes reproducteurs.

La prise en charge des SPJ est basée principalement sur la surveillance et le traitement des polypes hamartomateux. Il n′existe aucun traitement standarisé pour la pigmentation cutanéo-muqueuse. Le traitement fait appel à la cryochirurgie, la dermabrasion et au laser Q-switched.

Clinical utility of array comparative genomic hybridization: uncovering tumor susceptibility in individuals with developmental delay

Microarray-based comparative genomic hybridization can determine genome-wide copy number alterations at the kilobase level. We highlight the clinical utility of microarray-based comparative genomic hybridization in determining tumor susceptibility in 3 patients with dysmorphic features and developmental delay, likely decreasing both morbidity and mortality in these patients.

Laparoscopic management of small bowel intussusception in a 16-year-old with Peutz-Jeghers syndrome

INTRODUCTION

Peutz-Jeghers is a rare autosomal dominant disorder characterized by hamartomatous polyps and discoloration of mucosal membranes. The polyps can occur anywhere in the gastrointestinal tract and can grow large enough to cause bowel obstructions.

CASE REPORT

A 16-year-old male presented to the emergency department with signs and symptoms of an acute bowel obstruction. He had 2 days of abdominal pain, obstipation, and vomiting. He had a previous history of a colonoscopy with polypectomy at age 4, and hyperpigmentation of his mucous membranes.

RESULTS

Computed tomographic (CT) scan revealed an intussusception of the small intestine. An exploratory laparoscopy found an intussusception of the mid jejunum. A laparoscopic-assisted small bowel resection was performed. Pathology showed a 5-cm polyp that acted as a lead point for the intussusception. Colonoscopy and upper endoscopy revealed 5 more polyps in the stomach and colon that were removed.

CONCLUSION

Small bowel obstructions can be managed successfully with minimally invasive approaches. The treatment of obstruction in these patients is to remove the offending hamartomatous polyp(s). The rest of the intestine needs to be examined and those polyps found should be removed. This can be done intraoperatively with laparoscopic-assisted enteroscopy and colonoscopy.

Allele loss and mutation screen at the Peutz-Jeghers (LKB1) locus (19p13.3) in sporadic ovarian tumours

Germline mutations in the LKB1 (STK11) gene (chromosome sub-band 19p13.3) cause characteristic hamartomas and pigmentation to develop in patients with Peutz-Jeghers syndrome. Peutz-Jeghers syndrome carries an overall risk of cancer that may be up to 20 times that of the general population and Peutz-Jeghers patients are at increased risk of benign and malignant ovarian tumours, particularly granulosa cell tumours. Loss of heterozygosity (allele loss, LOH) has been reported in about 50% of ovarian cancers on 19p13.3. LKB1 is therefore a candidate tumour suppressor gene for sporadic ovarian tumours. We found allele loss at the marker D19S886 (19p13.3) in 12 of 49 (24%) sporadic ovarian adenocarcinomas. Using SSCP analysis, we screened ten ovarian cancers with LOH, 35 other ovarian cancers and 12 granulosa cell tumours of the ovary for somatic mutations in LKB1. No variants were detected in any of the adenocarcinomas. Two mutations were detected in one of the granulosa cell tumours: a mis-sense mutation affecting the putative 'start' codon (ATG --> ACG, M1T); and a silent change in exon 7 (CTT --> CTA, leucine). Like BRCA1 and BRCA2, therefore, it appears that LKB1 mutations can cause ovarian tumours when present in the germline, but occur rarely in the soma. The allele loss on 19p13.3 in ovarian cancers almost certainly targets a different gene from LKB1.