High Resolution Melting analysis as a rapid and efficient method of screening for small mutations in the STK11gene in patients with Peutz-Jeghers syndrome

Abstract

BackgroundPeutz-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.MethodsThe 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.ResultsIn 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.ConclusionsThe 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.

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

“…The gene STK11 includes 22637 base pairs and 10 exons, 9 of which contain a coding sequence of 48.6 kDa protein, which fulfils the function of serine-threonine kinase 3 6. It is a suppressor gene, and the kinase encoded by it plays an important role in cell metabolism regulation and proliferation, cell polarity, p53-mediated apoptosis and in other signalling pathways 3 6 9…”

“…Until now, over 230 distinct STK11 gene mutations with a heterogeneous nature have been identified in the Human Gene Mutation Database: 72 point missense/nonsense mutations and 26 mutations in splicing sites, as well as 102 small insertions, deletions and indel-type mutations 2 6. The remaining 31 mutations described concern rearrangements of larger fragments of the STK11 sequence, including 25 large deletions, 3 large insertions and 3 combined mutations 2 6.…”

“…The remaining 31 mutations described concern rearrangements of larger fragments of the STK11 sequence, including 25 large deletions, 3 large insertions and 3 combined mutations 2 6. Interestingly, a notable proportion of PJS samples do not carry any mutation in STK11, suggesting possible genetic heterogeneity in the disease and the potential existence of another causative genetic locus, yet to be identified 3 6 7…”

“…Although a number of STK11 gene mutations (serine/threonine-protein kinase 11) have been increasingly identified in 50–90% of sporadic and in almost 100% of familial cases,3 6 7 wide genetic heterogeneity is recognised and genotype–phenotype associations are not yet clearly established 8–10…”

The pattern of STK11 gene mutation and its phenotypical manifestation in patient with hamartomas polyposis

“…Етапи HRM проводили від +60 до +90 °С, збільшуючи температуру на 0,1º на кожен крок. Отримані плоти аналізували з використанням Rotor-Gene Software: 2.0.2 [3,11]. Молекулярно-генетичний аналіз зразків ДНК виконували в Інституті генетики лю-дини ПАН (Познань, Польща) на основі наукової співпраці.…”