The Impact of Genotype on Bone Complications in Beta Thalassemia Major Patients

Abstract

Background: Specific genetic mutations in β ‑ thalassemia lead to complete lack of β ‑ globin chain production, considered as β° thalassemia, others allow some synthesis of the β-globin and are known as β + thalassemia. Patients need regular blood transfusions to  correct anemia and iron-chelating therapy, to control iron overload. Severe anemia, along with excess body iron, and chelation therapy,  can result in complications, as bone abnormalities, growth retardation, liver, cardiac, and endocrine disorders.

Methods: Cross sectional study subjected to record the impact of genotype on occurrence of bone complications in β-thalassemia cases,while 50 thalassemic cases involved from July 2017 to June 2018. DNA sequencing allowed for the cases' genotype identification.  Bone density is evaluated using a dexa scan, translated into a Z-score compared to an appropriate reference, as well as bone imaging and  laboratory investigations, which all evaluated as biochemical variables.

Results: Low bone mineral density was the commonest bone complication, while osteoporosis and osteopenia represented 34% and 28% respectively, other bone problems presented in 16% of cases. Additionally, a positive correlation between occurrence of osteoporosis, older patients, longer transfusion times, high ferritin levels, and  longer transfusion gaps. The three most common mutations discovered were IVS1-110, IVS1-1, and IVS1-6 (28, 26, and 16%, respectively).  The β°β° genotype showed a significantly high incidence of complications and low bone density compared to those with β°β+ and β +β +  genotypes.

Conclusion: Bone complications are common association in βthalassemia major cases with a clear correlation between  genotype and  clinical disease progression as well as its severity.