MTHFR C677T Polymorphism, Plasma Homocysteine, and PDGF-AA Levels and Transcranial Doppler Velocity in Children With Sickle Cell Disease

Objective: To evaluate the effect of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism on plasma homocysteine (tHcy) and platelet-derived growth factor (PDGF-AA) levels in children with sickle cell disease (SCD), and ascertain their role in predicting high transcranial doppler velocity (TCD). Methods: We estimated MTHFRC677T gene polymorphism, plasma tHyc and PDGF-AA in 44 SCD patients and 44 healthy children. Results: The prevalence of mutant homozygous MTHFR (C677TT) in SCD was 13.6%. Significantly higher plasma tHcy was observed in mutant homozygous MTHFRC677TT patients. Significantly higher plasma tHcy and PDGF-AA levels were observed in SCD patients than in controls. Median (IQR) PDGF-AA levels were significantly higher in conditional and high-risk TCD patients as compared to low-riskTCD patients [325 (93.1-368) and 368 (111-480) vs 111 (56-201) pg/mL, respectively; P<0.001]. Mean (SD) tHcy levels were significantly higher in high-risk TCD children than low-risk TCD children (12.9 (2.7) vs 9.9 (2.5) µmol/L; P=0.006). The receiver operating characteristic revealed that the area under the curve (AUC) of PDGF-AA for high TCD velocity was 0.934 (95% CI 0.845-1.00; P<0.001) and tHcy had an AUC of 0.675 (95% CI 0.517-0.833; P=0.04). Conclusion: PDGF-AA and tHcy levels could be used as predictive markers for stroke in SCD children. MTHFR Polymorphism contributes to elevated tHcy levels.