Detecting rare thalassemia in children with anemia using third-generation sequencing

Area of Science:

• Genetics
• Molecular Biology
• Pediatric Hematology

Background:

• Conventional genetic testing in China is limited to common thalassemia variants.
• Accurate diagnosis of rare thalassemia is critical for pediatric anemia management, particularly for those requiring blood transfusions.
• Third-generation sequencing (TGS) offers potential for comprehensive genetic analysis.

Purpose of the Study:

• To evaluate the diagnostic utility of third-generation sequencing (TGS) for rare thalassemia in anemic children.
• To identify both known and novel thalassemia genotypes in pediatric patients.
• To assess the clinical implications of identified rare thalassemia genotypes.

Main Methods:

• Enrolled 20 anemic children, excluding iron deficiency anemia (IDA).
• Employed third-generation sequencing (TGS) for comprehensive genotype identification.
• Utilized Sanger sequencing for confirmation of novel mutations.

Main Results:

• Identified 5 cases of rare thalassemia among the 20 participants.
• Detected various genotypes including HBB, HBA2, and HBD gene mutations, and a novel -SEA/α-91α genotype associated with severe non-deletional hemoglobin H disease (HbH disease).
• Correlated specific genotypes (β654/β-4.9, -SEA/α-91α) with the need for long-term blood transfusions and others (-SEA/αCD30α, Chinese Gγ+(Aγδβ)0, delta thalassemia) with mild anemia.

Conclusions:

• Third-generation sequencing (TGS) shows significant promise for diagnosing rare thalassemia in children.
• TGS is particularly valuable for identifying transfusion-dependent thalassemia (TDT) cases.
• This advanced sequencing method aids in precise clinical diagnosis and management strategies for pediatric thalassemia.