ABSTRACT
To assess the roles of genetic modifiers in Iraqi ß-thalassemia patients, and determine whether a genotype-based scoring system could be used to predict phenotype, a total of 224 Iraqi patients with molecularly characterized homozygous or compound heterozygous ß-thalassemia were further investigated for α-thalassemia deletions as well as five polymorphisms namely: rs7482144 C > T at HBG2, rs1427407 G > T and rs10189857 A > G at BCL11A, and rs28384513 A > C and rs9399137 T > C at HMIP. The enrolled patients had a median age of 14 years, with 96 males and 128 females. They included 144 thalassemia major, and 80 thalassemia intermedia patients. Multivariate logistic regression analysis revealed that a model including sex and four of these genetic modifiers, namely: ß+ alleles, HBG2 rs7482144, α-thalassemia deletions, and BCL11A rs1427407 could significantly predict phenotype (major versus intermedia) with an overall accuracy of 83.9%. Furthermore, a log odds genetic score based on these significant predictors had a highly significant area under curve of 0.917 (95% CI 0.882-0.953). This study underscores the notion that genetic scoring systems should be tailored to populations in question, since genetic modifiers (and/or their relative weight) vary between populations. The population-oriented genetic scoring system created by the current study to predict ß-thalassemia phenotype among Iraqis may pave the way to personalized medicine in this patient's group.
Subject(s)
Phenotype , Polymorphism, Single Nucleotide , Precision Medicine , Repressor Proteins , beta-Thalassemia , Humans , beta-Thalassemia/genetics , beta-Thalassemia/diagnosis , Male , Female , Iraq , Adolescent , Child , Genotype , Alleles , Adult , Young Adult , Child, Preschool , alpha-Thalassemia/genetics , alpha-Thalassemia/diagnosisABSTRACT
OBJECTIVES: We sought to assess the complications and challenges facing the management of ß-thalassemia major (ß-TM) in Iraq. METHODS: A total of 150 consecutive patients with ß-TM who were registered at a main thalassemia center in Northern Iraq were enrolled in the study. The patients had their records reviewed, were clinically evaluated, and investigated for various complications. RESULTS: Our patient cohort had a median age of 13 years (range: 1-35 years) and a male to female ratio of 1:1.2. Their median serum ferritin was 2762 µg/L, all were on regular transfusions, 94.7% were on chelation therapy, and 38.0% were splenectomized. Pre-transfusion hemoglobin levels were 3 9.0 g/dL in 38.7% of the patients. Short stature was encountered in 33.9% of those aged ≤ 20 years, and skeletal changes were noted in 50.7%. Iron overload associated complications, including hypogonadism, hypothyroidism, hypoparathyroidism, diabetes mellitus, and heart failure, were encountered in 52.8%, 7.3%, 3.3%, 3.3%, and 2.7%, respectively. Hepatitis C virus (HCV) antibodies were detectable in 35.3%, while HIV antibodies and hepatitis B surface antigen were not detectable in any. Patients with diabetes mellitus, heart failure, HCV antibodies, and hypoparathyroidism were significantly older than those without these complications. Hypogonadism was the only complication associated with significantly higher serum ferritin levels. Hypogonadism, heart failure, HCV antibodies, and diabetes were significantly more frequent among the splenectomized patients. CONCLUSIONS: The management of ß-TM in this cohort of Iraqi patients is still suboptimal, and the need to ensure timely transfusions and optimize chelation, as well as a more robust iron overload assessment, should be underscored.
