Molecular Diagnostics of β-Thalassemia

Differentinating between non-transfusion dependant β-thalassemia and iron deficinecy anemia in children using ROC and logistic regression analysis: two novel discrimination indices designed for pediatric patients

Introduction

This cross-sectional study enrolled a group of 271 children with microcytic anemia in order to test the performance of 41 single and 2 composite formulas andindices in distinguishing between β-thalassemia (β-thal) and iron deficiency anemia (IDA) in the pediatric population.

Methods

Optimal pediatric cut-off values from the previously published formulas and indices were generated using ROC analysis. Logistic regression in R using generalized linear models (GLM) generated two new indices.

Results

Formulas and indices with optimal cut-offvalues in children with accuracy ≥90% were (in descending order): Matos & Carvalho index, MDHL(Telmissani) formula, England and Fraser formula, Pornprasert index, Sirachainan index, Telmissani (MCHD) formula, CRUISE index, Hameed index, Sargolzaie formula and Zaghloul II index. The CroThalDD-LM1 index has an accuracy of 93.36% (AUC 0.986, 95% CI 0.975-0.997), while the second CroThalDD-LM2 index utilizes absolute reticulocyte count alongside CBC variables, with an accuracy of 96.77% (AUC 0.985, 95% CI 0.988-0.999).

Discussion and conclusion

We recommend using aforementioned formulas and indices with corrected cut-off values and accuracy >90% alongside two new proposed indices. A comparison of both native and these new indices is encouraged. These are the first discrimination indices generated and designed precisely for the pediatric population, which includes preschool children.

β globin mutations in Turkish, Northern Iraqi and Albanian patients with β thalassemia major

The mutation detection of β thalassemia is absolutely necessary for molecular diagnosis, as well as any genetic epidemiological study. The β globin gene has 3 exons and 2 introns, involved in β-thalassemic pathogenesis. The study aim of the study is to characterize the spectrum of β globin gene mutations in 136 Turkish, Northern Iraqi and Albanian pediatric β thalassemia major patients. After genomic DNA extraction from venous blood and amplification of the target DNA regions with PCR, genotyping was achieved by Sanger based DNA sequencing. The IVSI-110 G>A mutation was the most frequent allele in the Turkish and Albanian patients. In Northern Iraqi patients IVSI-1 G>A was is the most frequent. There are two mutations are firstly reported for Albania [c.*111 A>G 3’ UTR (rs63751128) and c.113 G>A (p.Trp38Ter, p.W38*) (rs35887507)] with this study. These findings may be of value for genetic counseling, premarital diagnosis, prenatal diagnosis and prevention programs.