مختصر البحث:
Background: The association between a vitamin D receptor gene (VDR) and autism spectrum disorder (ASD) in
some ethnic groups is still inconclusive, among Iraq's Arab population, this association hasn't been highlighted as
yet.
Methods: Two hun…
Background: The association between a vitamin D receptor gene (VDR) and autism spectrum disorder (ASD) in
some ethnic groups is still inconclusive, among Iraq's Arab population, this association hasn't been highlighted as
yet.
Methods: Two hundred and eighteen ASD children were examined; 171 males and 47 females (mean age 6.91 ±
4.11 years). The control group was 211; 162 were males and the rest were females. The purpose of this study was
to identify a correlation between four single nucleotide polymorphisms (SNPs); TaqI (rs731236), FokI
(rs2228570), ApI (rs7975232) and BsmI (rs1544410) in the VDR using polymerase chain reaction–restriction
fragment length polymorphism (PCR–RFLP) with susceptibility to childhood ASD. An Enzyme-linked immunosorbent assay (ELISA) was used to assess serum vitamin D and vitamin D receptor levels.
Results: There was a statistically significant increase in the prevalence of the CC genotype and the C allele in VDR
TaqI (rs731236) among patients compared to controls [15.6% vs. 1.8%, OR = 4.39, 95% CI = 2.18–8.81, p =
0.001] and [34.6% vs. 23.2%, OR = 1.74, 95% CI = 1.30–2.32, p = 0.001] respectively. Furthermore, the frequency of the variant CC genotype and C allele of the FokI in codominant model increased significantly in ASD
patients than in the controls [23.8% vs. 6.5%, OR = 4.20, 95% CI = 2.22–7.96, p = 0.001] and [34.2% vs. 20.9%,
OR = 1.97, 95% CI = 1.44–2.67, p = 0.001] respectively. In addition, the frequency of CC genotype increased
significantly in the recessive models of TaqI (rs731236) and FokI (rs2228570) in ASD patients compared to
controls (15.6% vs. 1.8% OR = 9.56, 95% CI = 3.32–27.4, p = 0.001) and (27.2% vs. 6.7%, OR = 4.40, 95% CI =
2.35–8.23, p = 0.001), respectively. Mean serum VDR levels decreased significantly in ASD patients with both CC
genotypes of TaqI (rs731236) than TT genotypes (P = 0.026) and in CC genotypes of FokI (rs2228570) than TT
genotypes (p = 0.012). Moreover, vitamin D and VDR levels were considerably lower in ASD patients than in
controls respectively (p = 0.0001).
Conclusions: Our findings demonstrate that specific polymorphisms TaqI (rs731236) and FokI (rs731236) in VDR
were high risk factors for developing childhood ASD in the Iraqi Arab population.
