Genetic polymorphism in the Methylentetrahydrofolate Reductase Gene Associated with Acute Lymphatic Leukemia in a Sample of Iraqi Patients

Acute Lymphocytic Leukemia (ALL) is a type of leukemia that differentiate from other types by the  continuous multiplication and overproduction of  immature and malignant white blood cells in the bone marrow. This study was aimed to investigat the relationship between the rs1801133 polymorphism in Methylenetetrahydrofolate reductase (MTHFR) with the susceptibility and severity of ALL.   A total of 35 blood samples were collected from all patients of both genders with mean age of 36.5 years, as well as 10 blood samples were collected from apparently  healthy controls with mean age of 33.5 years . results showed that there is a significant difference (p<0.05)between blood counts of neutrophils ,lymphocytes , red blood cells, hemoglobin, hematocrit and platelets in blood samples of all patients and healthy controls. To determine the relationship between functional MTHFR polymorphism C677T in association with the incidence of ALL in a sample of Iraqi patients,Genomic DNA was extracted from peripheral blood samples of ALL patients and healthy controls, then MTHFR exon 4 was amplified using specific primers and sequenced to determine the expected SNP. Results showed that the concentration of genomic DNA after extraction was ranged between 50 and 95Mg/ µl with purity of 1.8_1.93. On the other hand results of amplification showed that an amplified product of 198bp was obtained after electrophoresis on agarose gel (2%) represents the complete fragment of MTHFR exon 4 . To investigate the genetic polymorphism in exon 4, the nucleotide sequence of the amplified product was determined . Results showed that the single nucleotide polymorphism in the rs801133 was tSNP in ALL patients instead of cSNP in healthy controls, and it was found that the frequency of polymorphic heterozygous CT genotypes was higher
than polymorphic homozygous alleles TT .The MTHFR 677C   Tsubstitution creates a HinfI restriction site. To test this fact, amplified MTHFR exon 4 was digested with HinfI restriction enzyme, and
visualized after electrophoresis on 3% agarose gel with ethidium bromide  . Results of restriction digestion showed that heterozygotes alleles (677CT) produced three fragments of 198 , 175 and 23bp , while the homozygotes alleles (677TT) produced only two fragments of 175 and 23bp. This result confirmed the occurring of polymorphism at rs1801133 in exon 4 of MTHFR gene in ALL patients , which regarded as a molecular and prognostic biomarker for incidence of ALL.