A Rare Hemoglobin Variant Detected in a Pregnant Chinese Woman

Hemoglobin Variant (HBB:c.155 C>A) is a rare mutation caused by β-globin gene mutation called Hemoglobin North Manchester. So far, its existence has no adverse effect on human body, and it is a rare benign hemoglobin variant.

We reported a 32-year-old pregnant woman with discordant HbA1c and glucose measurements. In 75 g oral glucose tolerance test (OGTT), the pregnant woman got hyperglycemia at 1h-OGTT and 2h-OGTT. However, the pregnant woman had a low HbA1c of 3.9%. Subsequently, gene sequencing identified a rare mutation in the gene (HBB:c.155 C>A).

We report for the first time that a case of North Manchester mutation in a Chinese female patient. In this case, it was found that the North Manchester variant could affect the examination of HbA1c when measured by ion-exchange high-performance liquid chromatography (HPLC), causing in falsely low HbA1c.

Hemoglobin variants may lead to false HbA1c measurement. Clinicians should consider hemoglobin variants when HbA1c results are inconsistent with other laboratory tests.