Genotype-phenotype correlation in alpha-thalassemia: predicting genetic subgroups via laboratory parameters

Area of Science:

• Hematology
• Genetics
• Molecular Biology

Background:

• Alpha-thalassemia is a genetic blood disorder caused by deletions or mutations.
• Genotype-phenotype correlations in Saudi Arabia are not well-documented.
• Understanding these correlations is crucial for accurate diagnosis and management.

Purpose of the Study:

• To investigate if specific laboratory parameters can predict the underlying genetic subgroup of alpha-thalassemia.
• To compare hematological parameters between alpha-thalassemia deletion and mutation groups.

Main Methods:

• Retrospective analysis of 378 patients with genetically defined alpha-thalassemia (2017-2024).
• Comparison of complete blood count, hemoglobin electrophoresis, and ferritin levels between mutation and deletion groups.
• Statistical analysis using Mann-Whitney U, independent samples t-tests, and chi-square tests.

Main Results:

• The mutation group showed significantly higher indirect bilirubin, red cell distribution width (RDW), and Hemoglobin H (HbH) detectability compared to the deletion group.
• These differences persisted even after adjusting for sickle hemoglobin (HbS) levels.
• No significant difference in ferritin levels was observed between the groups.

Conclusions:

• Alpha-thalassemia mutations result in a distinct hematologic phenotype compared to deletions.
• Increased RDW, indirect bilirubin, and HbH can serve as potential markers to distinguish between alpha-thalassemia subtypes.
• These findings suggest different pathophysiological mechanisms and a potentially more severe hemolytic phenotype in mutation-driven alpha-thalassemia.