Diagnosis of Sickle Cell Disease and HBB Haplotyping in the Era of Personalized Medicine: Role of Next Generation Sequencing

Abstract

Hemoglobin genotype and HBB haplotype are established genetic factors that modify the clinical phenotype in sickle cell disease (SCD). Current methods of establishing these two factors are cumbersome and/or prone to errors. The throughput capability of next generation sequencing (NGS) makes it ideal for simultaneous interrogation of the many genes of interest in SCD. This study was designed to confirm the diagnosis in patients with HbSS and Sβ-thalassemia, identify any ß-thal mutations and simultaneously determine the ßS HBB haplotype. Illumina Ampliseq custom DNA panel was used to genotype the DNA samples. Haplotyping was based on the alleles on five haplotype-specific SNPs. The patients studied included 159 HbSS patients and 68 Sβ-thal patients, previously diagnosed using high performance liquid chromatography (HPLC). There was considerable discordance between HPLC and NGS results, giving a false +ve rate of 20.5% with a sensitivity of 79% for the identification of Sβthal. Arab/India haplotype was found in 81.5% of βS chromosomes, while the two most common, of the 13 β-thal mutations detected, were IVS-1 del25 and IVS-II-1 (G>A). NGS is very versatile and can be deployed to simultaneously screen multiple gene loci for modifying polymorphisms, to afford personalized, evidence-based counselling and early intervention.

Population characterization of mutations for sickle cell anemia and its treatment: One step towards personalized medicine for the disease

“…Con la aparición de estos nuevos fármacos, se pone de manifiesto la importancia de disponer de herramientas que identifiquen polimorfismos en grupos poblacionales y mejoren la personalización de los tratamientos para la ACF y otras patologías. Sin embargo, en la literatura se han descrito esfuerzos para personalizar el tratamiento para la ACF con hidroxiurea mediante el cálculo y ajuste de dosis específicas individuales 24,25 .…”

Special Issue “Personalized Medicine in Blood Disease of Children”

“…Adekile A. et al provided insights on the role of next-generation sequencing (NGS) in hemoglobinopathies, focusing on 159 patients with sickle cell anemia and 68 Sβ-thalassemia patients, previously diagnosed through the use of high-performance liquid chromatography. The authors stressed that for complete and comprehensive disease management, it is necessary to determine each patient’s genotype, considering the different polymorphisms that significantly modulate the phenotype and predispose the individual to, or protect them from, different complications [ 3 ].…”

“…These articles underline the fact that the phenotype has a multi-genic basis and NGS can be deployed to simultaneously screen relevant panels to afford personalized, evidence-based counseling and early intervention [ 3 , 4 ].…”

Insights in Thalassemia: From Genomics to Clinical Practice

“…TALENs are considerably easier to design compared to ZFNs, thus explaining their widespread use. Ma et al (41) combined the integration-free β-thalassemia induced pluripotent stem cells (iPSCs) derived from patients and TALEN-based universal correction of β-globin mutations in situ. This robust process has successfully corrected the HBB and the corrected iPSCs can be induced to differentiate into hematopoietic progenitor cells and then further to erythroblasts expressing normal β-globin.…”