Background: Thiopurine S-methyltransferase (TPMT) is a cytosolic enzyme that catalyses the S-methylation of 6-mercaptopurine and azathioprine. Low activity phenotypes are correlated with polymorphism in the TPMT gene. Patients with low or undetectable TMPT activity could develop severe myelosuppression when they are treated with standard doses of thiopurine drugs. Since ethnic differences in the TPMT gene polymorphism have been demonstrated worldwide, assessing it in the Libyan population is worthwhile. Methods: We investigated TPMT gene polymorphism in a total of 246 Libyan healthy adult blood donors from three different Libyan regions (Tripoli, Yefren, and Tawargha) and 50 children with acute lymphoblastic leukaemia (ALL). We used polymerase chain reaction restriction length polymorphism (PCR-RFLP) and allele-specific PCR-based assays to analyse the TPMT gene for the variants* 2 c. 238 G> C,* 3A (c. 460 G> A and c. 719 A> G),* 3B (c. 460 G> A), and* 3C (c. 719 A> G). Results: Our results show that the TPMT variants associated with low enzymatic activity were detected in 3.25%(8 in 246) of adult Libyan individuals and the frequency of total mutant alleles was 1.63%. Heterozygous genotypes were TPMT* 3A in three subjects (0.61%) and TPMT* 3C in five subjects (1.02%). No TPMT* 2 and TPMT* 3B allelic variants and no homozygous or compound heterozygous mutant alleles were detected. The normal allele (wild-type) was found in 98.4% of the adult individuals studied. No mutant alleles were detected among the 50 children who had ALL. arabic 10 English 74
Hamza Ben Zeglam, Abdulla Bashein, (1-2015)

Objective: In Libya, no pertussis booster doses are administered to children after 18 months of age. In light of evidence of waning of vaccine-induced immunity to pertussis, this study aimed to evaluate the waning of immunity in vaccinated school-entry age children, as measured by susceptibility to infection at population level. For this purpose, IgG and IgA levels were measured as markers of recent (infection in the last 6 months) and non-recent infections (infection in the last 12 months). Material and Methods: This was a cross sectional study undertaken in Tripoli, in February 2015. Children of school-entry age (> 5 to ≤ 7 years) were recruited on convenience basis at vaccination centers. Sera were tested for antibodies to pertussis. Results: Samples from791 children (421 males and 370 females, mean age 6.50 were tested). All of the participants had received 4 doses of Whole cell pertussis containing vaccine in the first 2 years of life. The prevalence of recent and non-recent pertussis infection were 4.8% and 2.5%, respectively. The proportion of children with undetectable level of IgG was 76.1%. Conclusion: The findings of this study showed significant circulation of Bordetella pertussis among vaccinated children by school-entry age. The circulation of B. pertussis in this population may be an indirect sign of waned immunity, which is simply corroborated by the absence of detectable antibodies in 76.1% of the children. arabic 14 English 76
Suleiman Abusrewil, Abdulla Bashein(1-2019)

Background: Phenylketonuria (PKU) is one of the most common inborn errors of amino acids metabolism. It is an autosomal recessive disease that is caused by mutations in phenylalanine hydroxylase (PAH) gene. In the North Africa and Eastern Mediterranean region, E280K missense mutation and c.1055del.G frameshift mutation in PAH gene are one of the most common pathogenic mutations seen in PKU patients. Materials and Methods: In this study, we developed molecular protocols for rapid screening of the PKU patients for these two mutations. These protocols are based on hydrolysis probe real-time polymerase chain reaction technique using allele-specific probes labeled with 6-carboxyfluorescein (FAM) for wild-type (WT) and hexachloro-6-carboxyfluorescein (HEX) for mutant genotypes and Black Hole Quencher 1 as a quencher and high-resolution melting analysis using EvaGreen saturating dye. Results: There was complete accordance between the developed protocols in differentiating genotypes and they proved to be rapid, sensitive, and efficient for the detection and differentiation between WT, mutant, and heterozygous genotypes of the E280K and c.1055del.G mutations. Conclusions: These protocols allow easy molecular screening of the mutations studied among the families of affected people, especially for premarital screening. arabic 27 English 170
Abdulla Bashein(1-2017)