الفهرس 
BETA THALASSEMIA MAJOROnly 14 pages are availabe for public view
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Abstract
Background: low cardiac MRI T2* values occur in some β TM patients despite good compliance with chelation therapy, suggesting possible role of genetic factors in cardiac iron deposition.
Aim of the work: to estimate the prevalence of GSTM1 null genotype among children and adolescents with β TM and its relation with myocardial function assessed by tissue Doppler and cardiac iron overload assessed by cardiac MRI T2*.
Patients and methods: fifty children and adolescent with β TM and 50 healthy controls were enrolled. All Patients were ≥ 10 years old and with no other systemic diseases affecting cardiac function. All patients and controls underwent laboratory investigations including: CBC, Hb electrophoresis and GSTM1 genotyping. Patients had also mean serum ferritin measured and underwent echocardiography, tissue Doppler and cardiac MRI with T2* measured.
Results: Mean serum ferritin of the patients was 3526.16±2392.71 ng/ml and mean T2* value was 25.59±13.82 ms. 34 (68%) patients had no cardiac iron deposition (T2* >20 ms) while 12 (24%) had mild to moderate cardiac iron deposition (T2*=10-20 ms) and 4 (8%) patients had severe cardiac iron deposition (T2*<10 ms). Cardiac T2* was not correlated significantly with serum ferritin (r=-0.097, P=0.5008), LVEF (r=0.189, p= 0.3885) and E/A ratio (r=0.268, p=0.217).Null genotype was prevalent in 46% of patients and 40% of controls (p=0.69). Patients with null genotype had significantly shorter T2* (p=0.0202). No significant difference among patients with null and normal genotypes as regard serum ferritin (p=0.2308).Null patients had significantly higher LVEDD (P=0.002) and shorter ejection time (p=0.005). GSTM1 genotype status was the only factor of significance in cardiac iron prediction (p=0.002).
Conclusion: GSTM1 null genotype may predispose patients with β TM to cardiac iron overload as it is significantly associated with shorter T2*, whereas serum ferritin is not related to either T2* or GSTM1 genotype.