POLYMORPHIC DELETIONS OF GLUTATHIONE S-TRANSFERASES M1, T1 AND BLADDER CANCER RISK IN ALGERIAN POPULATION

Objective: Glutathione S-transferase mu 1 (GSTM1) and GST theta 1 (GSTT1) genes are two xenobiotic metabolizing genes in Phase II of the detoxification process. The polymorphisms of GSTM1, GSTT1 genes, and smoking are involved in many cancers such as bladder cancer. Our aim was to assess the role of smoking status and GSTM1 and GSTT1 null genotypes in bladder cancer development in Algerian population.Methods: The current case–control study included 175 bladder cancer patients and 188 controls matched for age, gender, and ethnic origin. The GSTM1 and GSTT1 genotypes were determined by multiplex polymerase chain reaction using blood genomic DNA. Possible associations of stage and grade with the obtained genotypes were also tested.Results: A significant associations were observed between bladder cancer risk and tobacco smoke (p value: p=1.21E-08), GSTM1 null genotype (p=0.018), GSTT1 null genotype (p=0.009), and GSTM1/GSTT1-double null genotype (p=0.001). The combined effect of smoking and testing deletions increased the risk of bladder cancer and the most important risk was observed among smokers carrying GSTM1/GSTT1-double null genotype (p=1.09E-05). No significant association was shown between stage and grade of bladder cancer and the testing genotypes.Conclusion: This study indicated that smoking, GSTM1 null, GSTT1 null, and GSTM1/GSTT1-double null genotypes individually represent a risk factor for bladder cancer in Algerian population. The interaction smoking gene increased the risk considerably. In fact, it is suggested that patients with cigarette smoking habit and combined GSTM1 and T1 genes deletion might be at increased risk of bladder cancer

Combined Computational-Experimental Analyses of CFTR Exon Strength Uncover Predictability of Exon-Skipping Level.

International audienceWith the increased number of identified nucleotide sequence variations in genes, the current challenge is to classify them as disease causing or neutral. These variants of unknown clinical significance can alter multiple processes, from gene transcription to RNA splicing or protein function. Using an approach combining several in silico tools, we identified some exons presenting weaker splicing motifs than other exons in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene. These exons exhibit higher rates of basal skipping than exons harboring no identifiable weak splicing signals using minigene assays. We then screened 19 described mutations in three different exons, and identified exon-skipping substitutions. These substitutions induced higher skipping levels in exons having one or more weak splicing motifs. Indeed, this level remained under 2% for exons with strong splicing motifs and could reach 40% for exons having at least one weak motif. Further analysis revealed a functional exon splicing enhancer within exon 3 that was associated with the SR protein SF2/ASF and whose disruption induced exon skipping. Exon skipping was confirmed in vivo in two nasal epithelial cell brushing samples. Our approach, which point out exons with some splicing signals weaknesses, will help spot splicing mutations of clinical relevance

Molecular and cellular basis of Waardenburg syndrome : from genetic to function of SOX10

Résumé non transmisSummary not transmitte

Identification and functional analysis of SOX10 missense mutations in different subtypes of Waardenburg syndrome.

International audienceWaardenburg syndrome (WS) is a rare disorder characterized by pigmentation defects and sensorineural deafness, classified into four clinical subtypes, WS1-S4. Whereas the absence of additional features characterizes WS2, association with Hirschsprung disease defines WS4. WS is genetically heterogeneous, with six genes already identified, including SOX10. About 50 heterozygous SOX10 mutations have been described in patients presenting with WS2 or WS4, with or without myelination defects of the peripheral and central nervous system (PCWH, Peripheral demyelinating neuropathy-Central dysmyelinating leukodystrophy-Waardenburg syndrome-Hirschsprung disease, or PCW, PCWH without HD). The majority are truncating mutations that most often remove the main functional domains of the protein. Only three missense mutations have been thus far reported. In the present study, novel SOX10 missense mutations were found in 11 patients and were examined for effects on SOX10 characteristics and functions. The mutations were associated with various phenotypes, ranging from WS2 to PCWH. All tested mutations were found to be deleterious. Some mutants presented with partial cytoplasmic redistribution, some lost their DNA-binding and/or transactivation capabilities on various tissue-specific target genes. Intriguingly, several mutants were redistributed in nuclear foci. Whether this phenomenon is a cause or a consequence of mutation-associated pathogenicity remains to be determined, but this observation could help to identify new SOX10 modes of action

Screening of MITF and SOX10 regulatory regions in Waardenburg syndrome type 2.

Waardenburg syndrome (WS) is a rare auditory-pigmentary disorder that exhibits varying combinations of sensorineural hearing loss and pigmentation defects. Four subtypes are clinically defined based on the presence or absence of additional symptoms. WS type 2 (WS2) can result from mutations within the MITF or SOX10 genes; however, 70% of WS2 cases remain unexplained at the molecular level, suggesting that other genes might be involved and/or that mutations within the known genes escaped previous screenings. The recent identification of a deletion encompassing three of the SOX10 regulatory elements in a patient presenting with another WS subtype, WS4, defined by its association with Hirschsprung disease, led us to search for deletions and point mutations within the MITF and SOX10 regulatory elements in 28 yet unexplained WS2 cases. Two nucleotide variations were identified: one in close proximity to the MITF distal enhancer (MDE) and one within the U1 SOX10 enhancer. Functional analyses argued against a pathogenic effect of these variations, suggesting that mutations within regulatory elements of WS genes are not a major cause of this neurocristopathy

Phenotypic similarities and differences in patients with a p.Met112Ile mutation in SOX10.: SOX10 mutations and phenotypic variability

International audienceWaardenburg syndrome (WS) is characterized by an association of pigmentation abnormalities and sensorineural hearing loss. Four types, defined on clinical grounds, have been delineated, but this phenotypic classification correlates imperfectly with known molecular anomalies. SOX10 mutations have been found in patients with type II and type IV WS (i.e., with Hirschsprung disease), more complex syndromes, and partial forms of the disease. The phenotype induced by SOX10 mutations is highly variable and, except for the neurological forms of the disease, no genotype-phenotype correlation has been characterized to date. There is no mutation hotspot in SOX10 and most cases are sporadic, making it particularly difficult to correlate the phenotypic and genetic variability. This study reports on three independent families with SOX10 mutations predicted to result in the same missense mutation at the protein level (p.Met112Ile), offering a rare opportunity to improve our understanding of the mechanisms underlying phenotypic variability. The pigmentation defects of these patients are very similar, and the neurological symptoms showed a somewhat similar evolution over time, indicating a potential partial genotype-phenotype correlation. However, variability in gastrointestinal symptoms suggests that other genetic factors contribute to the expression of these phenotypes. No correlation between the rs2435357 polymorphism of RET and the expression of Hirschsprung disease was found. In addition, one of the patients has esophageal achalasia, which has rarely been described in WS. © 2014 Wiley Periodicals, Inc

Description of four cases of death by methanol: the experience of the toxicology and pharmacology laboratory of Moroccan Poison Control Centre

Introduction: Methanol intoxication is a public health problem that mainly affects poor populations in developed and developing countries. Despite all the advanced treatment methods, high mortality rates are still observed due to late admission to hospital and late diagnosis and treatment. Many mass poisoning have been described, following the misuse of methanol in the manufacture of adulterated alcohol in some Eastern European, Asian and African countries, resulting in several hundred each year. Objective: The objective of our study was to describe four cases of methanol intoxication that were received by the au toxicology and pharmacology laboratory of the Moroccan poison control centre CAPM-LAB. Materiel and methods: The epidemiological characteristics of patients intoxicated and dying by methanol in a collective setting were described as well as the results. Ethanol and methanol were determined in whole blood by gas chromatography with a flame ionisation detector coupled to the Head speace (CPG-FID-HS). Results: Following the consumption of adulterated alcohol (locally prepared alcohol); the CAPM-LAB received three samples from the city of El-Hajeb. The patients were aged of 46, 58 and 26 years and presented visual and consciousness disorders and vomiting, they presented average methanolemia of 1,34g/l. The CAPM-LAB also received samples from another patient from the city of Marrakech, aged 44 years, following a collective intoxication (three people) with adulterated alcohol, with methanol level of 2,52g/l. The patients died as a result of heart failure. Conclusion: Methanol can cause fatal intoxication, due to its easy availability in our country and the illegal production of alcoholic beverages

Variations identified in <i>MITF</i> regulatory regions.

<p>(A) Schematic view of the MITF-M promoter and MDE enhancer regions showing binding sites for transcription factors known to regulate <i>MITF/Mitf</i> expression in melanocytes. Note the presence of several SOX10 binding sites in both promoter and enhancer regions. Grey arrows indicate the position of QMF-PCR primers. Black arrows indicate the position of primers used for PCR and sequencing screening. (B) Electropherogram showing the heterozygous variation identified. (C) Alignment of the nucleotide sequences of human MDE (GenBank accession number NT_022459) and its corresponding <i>Mus musculus</i> (NT_039353) and canine (AC191512.6) homologous regions. The asterisks indicate the identical nucleotides between murine, canine, and human sequences. The four putative SOX10 binding sites are indicated by black boxes. The previously described human MDE 298 bp region <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041927#pone.0041927-Watanabe1" target="_blank">[13]</a> is indicated in green. The location of the identified variation is indicated by a red open box. Note that it affects a nucleotide conserved between humans and mice, but not dogs.</p