RESUMEN
We report a rare hemoglobin (Hb) variant on the ß-globin gene, which was detected in a female from Yulin City, Guangxi Autonomous Region, People's Republic of China (PRC), during routine thalassemia screening. The Hb variant remained unnoticed using capillary electrophoresis (CE) and high performance liquid chromatography (HPLC), while an additional peak was observed by matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS). DNA sequencing revealed the GCC>GTC substitution at codon 13 on the ß-globin gene, causing a substitution of alanine to valine. The mutation is only described in the ITHANET database but no Hb variant name and other information, so we named it Hb Yulin after the place of origin of the proband in this study. Hb Yulin is clinically silent and easily leads to misdiagnosis during hemoglobinopathies screening based on the common methods of HPLC and CE.