Cytogenetic assessment of Fanconi anemia in children with aplastic anemia in Tunisia.

BACKGROUND: Chromosome breakage hypersensitivity to alkylating agents is the gold standard test for Fanconi anemia (FA) diagnosis. The aim of the present study was to assess the proportion of FA cases among aplastic anemia (AA) in Tunisian pediatric patients. OBSERVATION: Investigation of mitomycin C-induced chromosomal breakage was carried out in 163 pediatric patients with AA and siblings of the cases where diagnosis of FA was confirmed. We identified 31 patients with FA whose percentage of unstable mitoses ranges from 65% to 100%. Among 18 siblings who were investigated for chromosomal instability, 3 were incidentally found to be affected. CONCLUSIONS: FA is an important cause of AA in Tunisia. Our report is the first study in North Africa that explored cytogenetic and phenotypic findings in FA children. It also showed the importance of mitomycin C sensitivity screening in all FA siblings.

Differentiation of Fanconi anemia and aplastic anemia using mitomycin C test in Tunisia.

Fanconi anemia (FA) is a recessive chromosomal instability syndrome that is clinically characterized by multiple symptoms. Chromosome breakage hypersensitivity to alkylating agents is the gold standard test for FA diagnosis. In this study, we provide a detailed laboratory protocol for accurate assessment of FA diagnosis based on mitomycin C (MMC) test. Induced chromosomal breakage study was successful in 171 out of 205 aplastic anemia (AA) patients. According to the sensitivity of MMC at 50 ng/ml, 38 patients (22.22%) were diagnosed as affected and 132 patients (77.17%) as unaffected. Somatic mosaicism was suspected in an 11-year-old patient with a FA phenotype. Twenty-six siblings of FA patients were also evaluated and five of them (19.23%) were diagnosed as FA. From this study, a standard protocol for diagnosis of FA was developed. It is routinely used as a diagnostic test of FA in Tunisia.

Trichothecene chemotypes of Fusarium culmorum infecting wheat in Tunisia.

Fusarium culmorum is a major pathogen associated with Fusarium head blight (FHB) of wheat in Tunisia. It may cause yield loss or produce mycotoxins in the grain. The objectives of the present study were threefold: to evaluate by PCR assays the type of mycotoxins produced by 100 F. culmorum isolates recovered from different regions in Northern Tunisia, to determine the amount of mycotoxin production by HPLC analysis, and to analyse for correlations between the amount of mycotoxin produced and the aggressiveness of isolates. PCR assays of Tri5, Tri7, Tri13, and Tri3 were used to predict whether these isolates could produce nivalenol, 3-acetyl-deoxynivalenol, or 15-acetyl-deoxynivalenol. Two of the isolates were predicted to produce NIV, whereas the others were predicted to produce 3-AcDON. Trichothecene production was confirmed and quantified by high pressure liquid chromatography (HPLC) in 28 isolates, after growth on wheat grains, and in a liquid Mycotoxin Synthetic medium (MS). All strains produced DON/3-AcDON at detectable levels ranging from 21 microg/g to 11.000 microg/g of dry biomass on MS medium and from 10 microg/g to 610 microg/g on wheat grain. The evaluation of the relationship between 3-AcDON production and aggressiveness of 17 strains revealed a significant difference in aggressiveness among the isolates. Moreover, only a significant correlation was revealed between aggressiveness and the amount of 3-AcDON produced on MS medium (r=0.36). Chemotyping of F. culmorum isolates is reported for the first time for isolates from Tunisia, and highlights the important potential of F. culmorum to contaminate wheat with 3-AcDON trichothecenes.