Case report: A rare heterozygous Hb CS with heterozygous HbE in a family with thalassemia in China

Abstract

Thalassemia is a hemoglobin disease characterized by reduced or complete absence of the production of the α/β globin gene. Currently, the detection of β-thalassemia carriers is based on differences in blood cell parameters. However, β-thalassemia carriers cannot be distinguished from α- and β-thalassemia co-inherited carriers based solely on hematological findings, and the differential diagnosis must rely on molecular diagnosis. We report a 32-year-old male from Yunnan Province, who had abnormal hemoglobin E without obvious anemia. A rare α^CS (CD142, TAA→CAA) combined with a βE (CD26, GAG→AAG) double heterozygous mutation was identified in the proband by PCR-reverse dot blot (PCR-RDB) and DNA sequencing. Additionally, a family lineage analysis was performed. This study complements the spectrum of rare thalassemia gene variants and is critical for clinical genetic counseling.

Keywords: Case report; Genetic diagnosis; Hb E; Hemoglobin Constant Spring; Thalassemia.

Fig. 1

Identification of the thalassemia genotype. (A) Family pedigree. Circles: female members; squares: male members; (B–F) Hb analysis via capillary electrophoresis: (B) father, (C) mother, (D) proband, (E) sister, (F) daughter of the proband; (G) Genotype confirmation via PCR-RDB for the family; (H) The DNA sequencing revealed a heterozygous T/C mutation in α2; (I) The DNA sequencing revealed a heterozygous G/A mutation in β. Arrows indicate the positions of the mutations.