RESULTS
Demographic characteristics and laboratory
results
The mean age of the total patient group was 46.3 ± 25.9 months (median
46), and the mean age of the control group was 23.9 ± 13.4 months
(median 20) (p < 0.001). In the patient group, 37
(36.3%) of the cases were female, and 35 (40.7%) of the patients in
the control group were female; (p = 0.534). A comparison of the
demographic characteristics and laboratory results of the patient
subgroups is shown in Table 1.
Genetic workup with real-time
PCR
1. Genotype analysis of the studied
SNPs
1a. Comparison of total patient group and
controls
The genotypes were grouped as homozygote, heterozygote, or wild. After
determining the genotypic distribution, we performed a genetic
comparison according to the autosomal recessive inheritance pattern of
the ARG1 and ARG genes between the patients, controls, and
patient subgroups. There was no difference between the total patient
group and the healthy controls in terms of the homozygote genotype of
the SNPs in the ARG1 and ARG2 genes (Table 2).
1b. Comparison of patient
subgroups
The homozygote cytosine-cytosine (CC) genotype of the ARG1rs2781667T>C SNP in the EW group was significantly lower
than for the controls (p = 0.006) [OR (95% CI):
0.26(0.10–0.66)], the MW group (p = 0.002) [OR (95% CI):
0.19(0.06–0.52)], and the asthmatics (p = 0.025) [OR (95%
CI): 0.22(0.06–0.75)]. There was no difference in the distribution of
the other studied SNPs in the ARG1 and ARG2 genes between
the patient subgroups and the controls (Table 2).
1c. Association between the SNP analysis and allergic
rhinitis, aeroallergen sensitivity, number of aeroallergens detected as
positive in the skin prick test, and tobacco
exposure
The homozygote CC genotype of the ARG1 rs2781667T>C
SNP was more frequent in patients with AR than in those without AR
(49.1% and 21.3%, respectively, p = 0.007) [OR (95% CI):
3.56(1.48–8.56)].
There was no difference in the presence of aeroallergen sensitivity, the
number of aeroallergens detected as positive in the skin prick test,
tobacco exposure, and homozygote genotype distribution of any SNPs among
all the patient groups.
2. Haplotype analysis
2a. Comparison of total patient group and
controls
There was a statistically significant difference in terms of ARG 1
haplotype 5 (CT/T/G/T/T/CT) and ARG 1 haplotype 9 (C/T/G/T/T/T)
between the healthy controls and the patient group. The frequency of theARG1 haplotype 5 in the patient group was 9.8% and 1.2% in the
control group (p = 0.028) [OR (95% CI): 9.23(1.15–73.70)].
The frequency of ARG1 haplotype 9 in the patient group was 2%
and 11.6% in the control group (p = 0.016) [OR (95% CI):
0.15(0.03–0.71)]. There was no difference between the patient groups
and the controls in terms of other haplotypes in the ARG1 andARG2 genes (see Tables 3A and 3B).
2b. Comparison of patient
subgroups
The frequency of the ARG1 haplotype 2 (CT/T/AG/AT/CT/CT) was
significantly higher in the EW group than in the healthy control and MW
groups (p = 0.041) [OR (95% CI): 2.76(1.13–6.76)] and
(p = 0.014) [OR (95% CI): 5.88(1.49–25.0)], respectively.
The frequency of haplotype 5 was significantly higher in the EW group
than in the controls (p = 0.005) [OR (95% CI):
14.16(1.64–121.93)]. The ARG1 haplotype 4 (C/T/A/A/C/T) was
more frequent in the MW, asthmatics, and control groups than in the EW
group (p < 0.0001) [OR (95% CI):
7.77(2.54–23.7)], (p = 0.036) [OR (95% CI):
4.31(1.15–16.15)], and (p = 0.030) [OR (95% CI):
3.44(1.20–10.0)], respectively (see Tables 3A, 3B).
2c. Association between SNP analysis and allergic rhinitis,
aeroallergen sensitivity, number of aeroallergens detected as positive
in the skin prick test, and tobacco
exposure
ARG1 haplotype 4 was more frequent in patients with allergic
rhinitis than those without allergic rhinitis, 41.8% and 21.3%,
respectively (p = 0.046) [OR (95% CI): 2.65(1.10–6.41)].
There was no difference in terms of haplotype distribution and presence
of aeroallergen sensitivity, the number of aeroallergens detected as
positive in the skin prick test, and tobacco exposure among all the
patient groups.