Compound Heterozygosity for an Unstable Novel Hemoglobin Variant, Hb Dongguan [α52(E1)Ser→Cys (TCT>TGT); HBA1: c.158C>G], and the - -SEA (Southeast Asian) α-Thalassemia Deletion

First study to describe a novel HbA2: c.400A > C mutation and Hb Dongguan heterozygote in two unrelated Chinese families

OBJECTIVES

Here we report two rare α-globin chain variants in two unrelated families: Hb Val de Marne [α133(H16) Ser > Arg (AGC > CGC); HBA2: c.400A > C] and Hb Dongguan [α52(E6) Ser > Cys (TCT > TGT); HBA1: c.158C > G]. Notably, HBA2: c.400A > C is an unreported new variant in the third exon of the α₂ gene, and simple heterozygous unstable Hb Dongguan haematological characteristics are proposed for the first time.

METHODS

Hb analysis was performed by using capillary electrophoresis (CE). Twenty-three common mutations were detected using a suspension array system. Mutations were identified by DNA sequencing.

RESULTS

The CE results showed an abnormal peak with incomplete separation from Hb A at zone 8 in two members of Family 1. DNA sequencing confirmed the presence of Hb Val de Marne [α133(H16) Ser > Arg (AGC > CGC); HBA2: c.400A > C]. Five members of Family 2 exhibited an abnormal peak at zone 11, and DNA sequencing confirmed the presence of Hb Dongguan [α52(E6) Ser > Cys (TCT > TGT); HBA1: c.158C > G].

CONCLUSIONS

The discovery of HBA2: C.400A > C expands the existing spectrum of α-globin variants. The carriers of simple heterozygous Hb Dongguan generally do not have obvious clinical symptoms. The information in this study will help clinicians understand the screening, molecular diagnosis and clinical significance of Hb variants.

A New α Chain Variant, Hb Heilongjiang (HBA2: c.49A>C), Found During Hb A1c Measurement

We here report a new hemoglobin (Hb) variant found in a Chinese woman. The presence of the Hb variant can be easily recognized by HbA_1c procedures based on ion exchange high performance liquid chromatography (HPLC) or capillary electrophoresis (CE) techniques. DNA sequencing revealed a new point mutation (HBA2: c.49A>C) at codon 16, resulting in an amino acid substitution from lysine to glutamine. Moreover, the Hb variant affected Hb A_1c determination by VARIANT II Turbo 2.0 and D100. We named the new Hb variant Hb Heilongjiang for the birthplace of the proband.