French experts report on MUTYH-associated polyposis (MAP).

Recent years have been characterised by an improvement in our knowledge of genetic determinism of adenomatous polyposes and by the description in 2002 of a new entity called "MUTYH-associated polyposis" (MAP), related to biallelic mutations of this gene. Its autosomal recessive mode of inheritance contrasts with the autosomal dominant inheritance of the classical "familial adenomatous polyposis" (FAP), associated with an APC germline mutation. Although some phenotypic features may be of value to distinguish these two conditions, their clinical "spectra" largely overlap and the differential diagnosis may be difficult. The purpose of this expertise conducted under the auspices of the French Institut National du Cancer (INCa) was to assess the current state of knowledge on MUTYH-associated polyposis and to establish some recommendations in the field of molecular analysis (indications of tests and analysis strategies for affected patients and their relatives) and of clinical management based on available data in the literature, on the results from the French molecular genetics laboratories performing MUTYH analysis and on the opinions of biologists and clinicians experts (genetic counsellors and gastroenterologists). The risk of colorectal cancer among relatives carrying a monoallelic MUTYH mutation was also studied.

Surface microbial consortia from Livarot, a French smear-ripened cheese.

The surface microflora (902 isolates) of Livarot cheeses from three dairies was investigated during ripening. Yeasts were mainly identified by Fourier transform infrared spectroscopy. Geotrichum candidum was the dominating yeast among 10 species. Bacteria were identified using Biotype 100 strips, dereplicated by repetitive extragenic palindromic PCR (rep-PCR); 156 representative strains were identified by either BOX-PCR or (GTG)(5)-PCR, and when appropriate by 16S rDNA sequencing and SDS-PAGE analysis. Gram-positive bacteria accounted for 65% of the isolates and were mainly assigned to the genera Arthrobacter , Brevibacterium , Corynebacterium , and Staphylococcus . New taxa related to the genera Agrococcus and Leucobacter were found. Yeast and Gram-positive bacteria strains deliberately added as smearing agents were sometimes undetected during ripening. Thirty-two percent of the isolates were Gram-negative bacteria, which showed a high level of diversity and mainly included members of the genera Alcaligenes , Hafnia , Proteus , Pseudomonas , and Psychrobacter . Whatever the milk used (pasteurized or unpasteurized), similar levels of biodiversity were observed in the three dairies, all of which had efficient cleaning procedures and good manufacturing practices. It appears that some of the Gram-negative bacteria identified should now be regarded as potentially useful in some cheese technologies. The assessment of their positive versus negative role should be objectively examined.

Novel extraction strategy of ribosomal RNA and genomic DNA from cheese for PCR-based investigations.

Cheese microorganisms, such as bacteria and fungi, constitute a complex ecosystem that plays a central role in cheeses ripening. The molecular study of cheese microbial diversity and activity is essential but the extraction of high quality nucleic acid may be problematic: the cheese samples are characterised by a strong buffering capacity which negatively influenced the yield of the extracted rRNA. The objective of this study is to develop an effective method for the direct and simultaneous isolation of yeast and bacterial ribosomal RNA and genomic DNA from the same cheese samples. DNA isolation was based on a protocol used for nucleic acids isolation from anaerobic digestor, without preliminary washing step with the combined use of the action of chaotropic agent (acid guanidinium thiocyanate), detergents (SDS, N-lauroylsarcosine), chelating agent (EDTA) and a mechanical method (bead beating system). The DNA purification was carried out by two washing steps of phenol-chloroform. RNA was isolated successfully after the second acid extraction step by recovering it from the phenolic phase of the first acid extraction. The novel method yielded pure preparation of undegraded RNA accessible for reverse transcription-PCR. The extraction protocol of genomic DNA and rRNA was applicable to complex ecosystem of different cheese matrices.

[Identification and management of HNPCC syndrome (hereditary non polyposis colon cancer), hereditary predisposition to colorectal and endometrial adenocarcinomas]. / Identification et prise en charge du syndrome HNPCC (hereditary non polyposis colon cancer), prédisposition héréditaire aux cancers du côlon, du rectum et de l'utérus.

BACKGROUND: The HNPCC syndrome (hereditary non polyposis colon cancer) is an inherited condition defined by clinical and genealogical information, known as Amsterdam criteria. In about 70% of cases, HNPCC syndrome is caused by germline mutations in MMR genes, leading to microsatellite instability of tumor DNA (MSI phenotype). Patients affected by the disease are at high risk for colorectal and endometrial carcinomas, but also for small intestine, urothelial, ovary, stomach and biliary tract carcinomas. HNPCC syndrome is responsible for 5% of colorectal cancers. Identification and management of this disease are part of a multidisciplinary procedure. METHODS: 12 experts have been mandated by the French Health Ministry to analyze and synthesize their consensus position, and the resulting document has been reviewed by an additional group of 4 independent experts. MAIN RECOMMENDATIONS: The lack of sensitivity of Amsterdam criteria in recognizing patients carrying a MMR germline mutation led to an enlargement of these criteria for the recruitment of possible HNPCC patients, and to a 2-steps strategy, asking first for a tumor characterization according to MSI phenotype, especially in case of early-onset sporadic cases. The identification of germline MMR mutations has no major consequence on the cancer treatments, but influences markedly the long-term follow-up and the management of at-risk relatives. Gene carriers will enter a follow-up program regarding their colorectal and endometrial cancer risks, but other organs being at low lifetime risk, no specific surveillance will be proposed.

Studies on an isolated West Indies population: IV. Genetic study of hearing loss

Hearing troubles were found to be very frequent among inhabitants of French origin in a small Caribbean island. Segregation analysis of hearing loss was performed in 165 complete nuclear families and revealed that familial aggregation could be entirely explained by a single recessive gene with high frequency (0.40). Homozygous individuals for this gene would probably be more suscepticle to ototoxic agents than other individuals. High frequency of this gene may be due to a founder effect (AU)