OBJECTIVE: To analyze the genetic susceptibility of HLA-DQA1 allele to anaphylactoid purpura(AP)and its association with the clinical features in juvenile Hans residing in Inner Mongolia. METHODS: Seventy children with AP and ninety normal controls of Hans in Inner Mongolia were subjected to HLA-DQA1 genotyping with the use of polymerase chain reaction-sequence specific primer (PCR-SSP) technique. RESULTS: (1) The gene frequency of HLA-DQA1*0301 of AP group (33.4%) was significantly higher than that (10.6%) of control group (chi square=21.899, P<0.01). On the other hand, the gene frequencies of HLA-DQA1*0302 were 6.7% and 19% in the AP group and the control group respectively; a significant difference between them was seen (chi square=9.786, P<0.01); (2)The gene frequencies of both DQA1*0301 and DQA1*0302 in the cutaneous purpura simplex cases and the controls were not significantly different (P>0.05). The gene frequencies of DQA1*0301 of the cutaneous purpura cases associated with gastrointestinal, joint and renal impairment were 26.7%, 28.5% and 29.3% respectively, which were higher than that of the control group (10.6%); the differences were statistically significant (P<0.01, 0.01, 0.01; respectively). The gene frequencies of HLA-DQA1*0302(3.9%, 5.7% and 9.6%) for the cutaneous purpura cases associated with gastrointestinal, joint and renal impairment were significantly lower than that (19%) of the controls except renal impairment(P<0.01, 0.01, respectively). CONCLUSION: The allele of HLA-DQA1*0301 was probably a susceptible gene while HLA-DQA1*0302 was the protective one in AP of the children who were Han inhabitants in Inner Mongolia. The results of this study also revealed that patients with the allele of HLA-DQA1*0301 tended to involve gastrointestinal, joint and renal impairment.