Four Chinese patients with Hb Q-H disease were identified during thalassemia screening. The main hematological characteristics of Hb Q-H disease are that Hb A is absent, and Hb Q-Thailand (also known as G-Taichung, Mahidol, Kurashiki-I and Asabara) accounts for the majority of the total hemoglobin (Hb). The phenotype of this disorder is similar to that of deletional Hb H (beta4) disease.