Rim Frikha

A duplex polymerase chain reaction-restriction fragment length polymorphism for rapid screening of methylenetetrahydrofolate reductase gene variants: Genotyping in acute leukemia

Methylenetetrahydrofolate reductase (MTHFR; NM_005957.4) is the key enzyme for folate metabolism which plays in DNA biosynthesis and the epigenetic process of DNA methylation. MTHFR gene polymorphisms, the c. 677C>T and c. 1298A>C have been implicated as risk factors for several types of cancers as the acute leukemia.

Use of MTHFR C677T polymorphism and plasma pharmacokinetics to predict methotrexate toxicity in patients with acute lymphoblastic leukemia

BACKGROUND Methotrexate (MTX) is a key component of acute lymphoblastic leukemia (ALL) therapy, but it is associated with serious toxicities in a considerable number of patients. OBJECTIVES The aim of the current study was to determine which variables were associated with MTX toxicity in children, adolescents and young adults with ALL. MATERIAL AND METHODS In this prospective study, 35 patients with newly diagnosed ALL, treated according to the 58951 European Organization for Research and Treatment of Cancer - Childrens Leukemia Group (EORTC-CLG) protocol, were prospectively enrolled. Toxicity data was collected objectively after each high-dose methotrexate (HD-MTX) course. The risk factors of MTX toxicity were determined using multiple linear regression analysis, with age, gender, immunophenotype, risk group, plasma MTX levels, plasma homocysteine (HCY) levels, and MTHFR C677T included as independent variables. RESULTS Twenty-five (71.4%) patients experienced toxicity on at least 1 course of HD-MTX. In the univariate linear regression, the global toxicity score was associated with a significant rise in plasma HCY concentrations within 48 h after MTX administration (β = 0.4; R2 = 0.12; p = 0.02). In the multiple regression model, the global toxicity score was significantly associated with a higher MTX plasma levels at 48 h (β = 0.5; R2 = 0.38; p = 0.001) and CT 677 MTHFR genotype (β = 0.3; R2 = 0.38; p = 0.01). CONCLUSIONS Routine monitoring of plasma MTX concentrations is essential to detect patients at a high risk of MTX toxicity. MTHFR C677T genotyping may be useful for predicting MTX toxicity.

Wilson disease, genotype and infertility: is there a correlation?

Wilson disease (WD; OMIM#277900) is a rare autosomal recessive disorder of copper metabolism, caused by mutations in the ATP7B gene (ATPase, Cu transporting, beta polypeptide; OMIM#606882; 21 exons) and leading to hepatic or neurologic disease. The wide spectrum of symptoms in patients with Wilson’s disease raised the question whether these features are determined by the type of the ATP7B mutation. To date, more than 500 mutations have been identified in patients with Wilson disease [1], and genetic studies are also becoming available for clinical use, but the utility of direct mutation analysis is limited. In this report, we try to establish relationship between phenotype (WD) and genotype (mutation through ATP7B gene). It is about a nonconsanguineous couple from Sfax in south Tunisia, who attended our genetic counselling and underwent a genetic testing for primary infertility since 17 years and failures of assisted reproductive technology (ART). Karyotype was normal in both partners, semen analysis reveal a moderate Oligo-astheno-teratozoospermia since 18 years, hormonal status (FSH, LH and testosterone) was normal, so, an idiopathic male infertility was suspected. WD was diagnosed in the man at 24 years, based on neurologic symptoms and elevated 24-h urinary copper, and a specific treatment mainly by D-penicillamine (DPA) was indicated. For genetic diagnosis of WD, peripheral blood was firstly collected from the patient after obtaining an informed consent. Second, the genomic DNA was extracted from white blood cells by standard phenol–chloroform method. Finally, the ATP7B gene was amplified and sequenced using automated sequencer (ABI, Applied Biosystems, CA, USA). The patient was a compound heterozygote for both the H1069Q and H642G, respectively, in exon 14 and 6 of ATP7B gene. Similar familial case with infertility and WD was reported. The same mutation is found in relatives (Fig. 1). Since multiple failures of ART; a control semen analysis was indicated which revealed a severely altered sperm quality (from moderate Oligo-astheno-teratozoospermia to severe teratospermia) although clinical amelioration with DPA. On my knowledge, this is the first reported cases of infertility in WD. We speculate that the pathophysiological disturbances leading to organ damage in WD are not only for the liver and the brain. Here, the testis tissue is altered mainly by copper toxicity which promote oxidative stress. Thus, increased markers of oxidative damage, including lipid peroxidation, damaged proteins and DNA, might be implicated in the mechanism of infertility in WD [2]. Furthermore, the testis copper concentration and study of DNA fragmentation of sperm are necessary to confirm the association between infertility and copper toxicity during the disease. R. Frikha (&) N. B. Abdelmoula T. Rebai Laboratory of Histology, Faculty of Medicine of Sfax, 3029 Sfax, Tunisia e-mail: frikha_rim@yahoo.fr