We conducted a survey for glucose-6-phosphate dehydrogenase (G6PD) deficiency using blood samples from male outpatients of a local hospital in southern Vietnam. Most of the samples were from the Kinh (88.9%), the largest ethnic group in Vietnam, with a small number (11.1%) coming from the K'Ho, Chauma, Nung, and Tay minorities. We detected 25 G6PD-deficient cases among 1,104 samples (2.3%), and read the open reading frame of G6PD. A novel mutation (352T>C) predicting an aminoacid change of 118Tyr>His was found in a 1-year-old Kinh boy. His G6PD activity was estimated to be less than 10% residual activity, although he did not show chronic hemolytic anemia. Thus, we categorized this variant as Class II and named it G6PD Bao Loc. In the Kinh population, G6PD Viangchan (871G>A, 1311C>T, intron 11 nt93T>C), one of the most common variants in continental Southeast Asian populations, was the highest (6/19), followed by variants originating from the Chinese such as G6PD Canton (1376G>T) (5/19), G6PD Kaiping (1388G>A) (3/19), G6PD Gaohe (95A>G) (1/19), and G6PD Quing Yuan (392G>T) (1/19). In addition, G6PD Union (1360C>T) (2/19), which originated from the Oceania, was also detected. These findings suggest that the Kinh people are derived from various ancestries from continental Southeast Asia, China, and Oceania. In contrast, all of the 5 deficient cases in the K'Ho population were G6PD Viangchan, suggesting that they were very close to Southeast Asian populations such as the Khmer in Cambodia and the Lao in Laos. It is interesting that G6PD Mahidol (487G>A), another common variant in continental Southeast Asian populations in Myanmar, Thailand, and Malaysia, has not been detected from the Vietnamese
