Résumé
Objective To discuss the polymorphisms of asthma susceptibility gene ORMDL3 in infantile wheezing,in order to provide a theoretical basis for early diagnosis of asthma.Methods One hundred and fifty wheezing infants were recruited and divided into 2 groups as asthma predictive index(API) positive group(n =80) and negative group (n =70).Taqman probe was applied to detect the genotypes of 2 single nucleotide polymorphisms (SNPs)in childhood asthma susceptibility gene ORMDL3,which were rs4794820 and rs7216389.The genotype distributions were analyzed and compared between 2 groups,and the correlations among genotype distribution and tidal breath pulmonary function,fractional exhaled nitric oxide (FeNO) concentration,percentage of eosinophils (EOS％),serum immune globulin E (total IgE) levels respectively were also analyzed,respectively.Results (1) The frequencies of rs4794820 AG and rs7216389 TC heterozygotes in the API positive group were the highest,which were significantly higher than those in the negative group(58.75％ vs.31.42％,56.25％ vs.32.86％ respectively,all P ＜0.01).The frequencies of GG and TT homozygotes in the API negative group were the highest,which were significantly higher than those in the positive group (58.57％ vs.30.00％,57.14％ vs.31.25％ respectively,all P ＜0.01).(2)The time to reach the peak expiratory flow in tidal breathing over the total expiratory time (TPTEF/TE) and the volume to reach the peak expiratory flow in tidal breathing over the total expiratory volume (VPEF/VE) of the infants in the API positive group were less than those in the API negative group(16.87 ±5.31 vs.20.12 ± 5.23,20.87 ± 5.92 vs.25.56 ± 6.77,respectively),and the FeNO concentration was higher than that in the API negative group [(22.44 ± 9.77) ppb vs.(13.23 ± 7.90)ppb],and the differences were significant (t =-3.776,-4.490,6.377,respectively;all P ＜ 0.01).(3) In the API positive group,the TPTEF/TE and VPEF/VE of the infants who expressed AG/TC genotype were lower than those who expressed GG/TT genotype (14.55 ± 4.83 vs.19.91 ± 4.17,18.85 ± 4.26 vs.25.20 ± 7.06,respectively,t =-4.727,-3.976,all P ＜ 0.01);while the FeNO concentrations,EOS％ and total IgE levels were higher than those who expressed GG/TT genotype [(25.02 ± 8.77) ppb vs.(18.39 ± 6.56) ppb,7.16 ± 2.62 vs.5.50 ± 1.34,(366 727 ±275 533) IU/L vs.(166 826 ± 62 865) IU/L,respectively] (t =3.484,3.409,4.589 respectively;all P ＜ 0.01).Conclusions Childhood asthma susceptibility gene ORMDL3 SNPs rs4794820 AG and rs7216389 TC heterozygotes are the risk factors for API positive infantile wheezing.The pulmonary function damage and airway inflammation of the infants who expressed AG/TC genotype are more serious than those who expressed GG/TT genotype,and more likely to develop persistent asthma.