Silent hemoglobin variant during capillary electrophoresis: A case report.

Hemoglobin (Hb) North Manchester [β51(D2) Pro→His; HBB:c.155 C>A] is a rare Hb β-globin gene variant that affects glycated Hb measurement values, such as ion-exchange high-performance liquid chromatography, in patients with diabetes. This variant was first detected in the UK in 1998. Here, we describe the first case involving Hb North Manchester detected incidentally in a patient with type 2 diabetes in Northern China. The Hb variant was discovered by ion-exchange high-performance liquid chromatography, yet capillary electrophoresis of both glycated Hb program and Hb program failed to detect it. Subsequently, Sanger sequencing was carried out to help identify the Hb variant.