3.1  Characteristics of the patients
Of 30 AA children, 56.70% (n=17) were boys, and 43.60% (n=13) were girls. The age ranged from 2 to 14 years, with a median age of 8 years. The percentages of non-severe AA, severe AA and very severe AA were 50.00%, 36.70% and 13.30%, respectively, in the 30 AA patients. There were no statistically significant differences in age or sex among the AA group, MDS group and control group.