Background: Previous studies have shown that the nicotinamide adenine dinucleotide (NAD+) precursors, nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR), protect against endogenously or exogenously induced DNA damage. However, whether the two compounds have the same or different efficacy against DNA damage is not clear. In the current study, we systematically compared the effects of NMN and NR on cisplatininduced DNA damage in HeLa cells. Methods: To evaluate the protective effects of NMN or NR, HeLa cells were pretreated with different doses of NMN or NR followed with 10 mu M of cisplatin treatment. Cell viability was examined by Trypan blue staining assay. For observing the DNA damage repair process, HeLa cells were treated with 10 mu M of cisplatin for 12 h, followed with 10 mM NMN or NR treatment for another 8, 16, 24, or 32 h, DNA damage levels were assessed for each time point by immunofluorescent staining against phosphor-H2AX (gamma H2AX) and alkaline comet assay. The effects of NMN and NR on intracellular NAD+ and reactive oxygen species (ROS) levels were also determined. Results: NMN and NR treatment alone did not have any significant effects on cell viability, however, both can protect HeLa cells from cisplatin-induced decrease of cell viability with similar efficacy in a dose -dependent manner. On the other hand, while both can reduce the DNA damage levels in cisplatin-treated cells, NR exhibited better protective effect. However, both appeared to boost the DNA damage repair process with similar efficacy. NMN or NR treatment alone could increase cellular NAD+ levels, and both can reverse cisplatin-induced decrease of NAD+ levels. Finally, while neither NMN nor NR affected cellular ROS levels, both inhibited cisplatininduced increase of ROS with no significant difference between them. Conclusion: NR have a better protective effect against cisplatin-induced DNA damage than NMN.

Pesticides are a group of extensively used man-made chemicals with high toxicity and strong residues, which are closely related to hearing health. Pesticide metabolite 3, 5, 6-Trichloro-2-pyridinol (TCP) exposure leads to neurotoxicity and auditory cell toxicity. However, whether TCP causes damage to hearing in adult mice is not clear. In this study, adult male C57BL/6 mice continuously exposed to TCP for 21 days showed a dose-dependent elevation of hearing threshold. Outer hair cells and spiral neuron cells were lost in a dose-dependent manner. Type I and V of spiral ligament were severely shrunk and stria vascularis were thinned in mice after 50 and 150 mg/kg TCP exposure. Similarly, ROS levels in the cochlea were significantly increased whereas the activities of anti-oxidation enzymes were decreased after TCP exposure. The expression level of Na+/K+ ATPase was decreased, resulting in cochlear potential disruption. Levels of inflammatory factors (TNF-alpha and IL-1(3), gamma-H2AX, and pro-apoptotic-related factors (Bax and cleaved-Caspase 3) were elevated, respectively. These results suggest that TCP can cause oxidative stress, inflammation, and imbalance of cochlear potential in the cochlea, induce cochlear DNA damage and apoptosis, and cause cochlear morphological changes, eventually leading to impaired hearing function.

The hypothesis of paternal origins of health and disease (POHaD) indicates that paternal exposure to adverse environment could alter the epigenetic modification in germ line, increasing the disease susceptibility in offspring or even in subsequent generations. p,p′-Dichlorodiphenyldichloroethylene (p,p′-DDE) is an anti-androgenic chemical and male reproductive toxicant. Gestational p,p′-DDE exposure could impair reproductive development and fertility in male offspring. However, the effect of paternal p,p′-DDE exposure on fertility in male offspring remains uncovered. From postnatal day (PND) 35 to 119, male rats (F0) were given 10 mg/body weight (b.w.) p,p′-DDE or corn oil by gavage. Male rats were then mated with the control females to generate male offspring. On PND35, the male offspring were divided into 4 groups according whether to be given the high-fat diet (HF): corn oil treatment with control diet (C-C), p,p′-DDE treatment with control diet (DDE-C), corn oil treatment with high-fat diet (C-HF) or p,p′-DDE treatment with high-fat diet (DDE-HF) for 35 days. Our results indicated that paternal p,p′-DDE exposure did not affect the male fertility of male offspring directly, but decreased sperm quality and induced testicular apoptosis after the high-fat diet treatment. Further analysis demonstrated that paternal exposure to p,p′-DDE and pre-pubertal high-fat diet decreased sperm Igf2 DMR2 methylation and gene expression in male offspring. Hence, paternal exposure to p,p′-DDE and pre-pubertal high-fat diet increases the susceptibility to male fertility impairment and sperm Igf2 DMR2 hypo-methylation in male offspring, posing a significant implication in the disease etiology.

Cuproptosis is characterized by lipoylated protein aggregation and loss of iron-sulfur (Fe-S) proteins, which are crucial for a wide range of important cellular functions, including DNA replication and damage repair. Sirt2 and sirt4 are lipoamidases that remove the lipoyl moiety from lipoylated proteins using nicotinamide adenine dinucleotide (NAD+) as a cofactor. However, to date, it is not clear whether nicotinamide mononucleotide (NMN), a precursor of NAD+, affects cellular sensitivity to cuproptosis. Therefore, in the current study, cuproptosis was induced by the copper (Cu) ionophore elesclomol (Es) in HeLa cells. It was also found that Es/Cu treatment increased cellular DNA damage level. On the other hand, NMN treatment partially rescued cuproptosis in a dose-dependent manner, as well as reduced cellular DNA damage level. In addition, NMN upregulated the expression of Fe-S protein POLD1, without affecting the aggregation of lipoylated proteins. Mechanistic study revealed that NMN increased the expression of sirt2 and cellular reduced nicotinamide adenine dinucleotide phosphate (NADPH) level. Overexpression of sirt2 and sirt4 did not change the aggregation of lipoylated proteins, however, sirt2, but not sirt4, increased cellular NADPH levels and partially rescued cuproptosis. Inhibition of NAD+ kinase (NADK), which is responsible for generating NADPH, abolished the rescuing function of NMN and sirt2 for Es/Cu induced cell death. Taken together, our results suggested that DNA damage is a characteristic feature of cuproptosis. NMN can partially rescue cuproptosis by upregulating sirt2, increase intracellular NADPH content and maintain the level of Fe-S proteins, independent of the lipoamidase activity of sirt2.

Hearing loss is a common chronic sensory deficit that affects millions of people worldwide and has emerged as a significant public health concern. The association between environmental exposure to chemicals and the prevalence of hearing impairment has recently attracted increased attention. Chlorinated paraffins (CPs) are a type of chemical compound that has been widely used and commonly detected in samples of both environmental and human origin. The knowledge of the toxicological effects of CPs, particularly its ototoxicity, remains limited at present. In this study, six commercial CPs were selected and evaluated using cochlea hair HEI-OC1 cells for their cytotoxicity, apoptosis, DNA damage, reactive oxygen species (ROS) accumulation and oxidative response. The cytotoxicity was observed after CPs exposure at high concentrations except for C-40 and was positively related to the chlorine content (Cl-content) in both CCK-8 and trypan blue assays. All 6 CPs induced cells apoptosis through caspase-dependent apoptotic pathway. CPs exposure induced DNA damage and stimulated ROS overproduction. Antioxidant N-acetyl-L-cysteine (NAC) could reverse the cytotoxicity and ROS accumulation caused by CPs exposure. The overexpression of ATF4 and CHOP indicated that endoplasmic reticulum (ER) stress was involved in the CPs induced cytotoxicity. Thus, CPs induced cytotoxicity and apoptosis via ROS accumulation, ER stress and DNA damage and positively related to the Cl-content and our findings indicate that CPs may pose a risk of ototoxicity at environmental relevant exposure levels.

The metabolite of organophosphate pesticide chlorpyrifos (CPF), 3,5,6-Trichloro-2-pyridinol (TCP), is persistent and mobile toxic substance in soil and water environments, exhibiting cytotoxic, genotoxic, and neurotoxic properties. However, little is known about its effects on the peripheral auditory system. Herein, we investigated the effects of TCP exposure on mouse postnatal day 3 (P3) cochlear culture and an auditory cell line HEI-OC1 to elucidate the underlying molecular mechanisms of ototoxicity. The damage of TCP to outer hair cells (OHC) and support cells (SC) was observed in a dose and time-dependent manner. OHC and SC were a significant loss from basal to apical turn of the cochlea under exposure over 800 μM TCP for 96 h. As TCP concentrations increased, cell viability was reduced whereas reactive oxygen species (ROS) generation, apoptotic cells, and the extent of DNA damage were increased, accordingly. TCP-induced phosphorylation of the p38 and JNK MAPK are the downstream effectors of ROS. The antioxidant agent, N-acetylcysteine (NAC), could reverse TCP-mediated intracellular ROS generation, inhibit the expressive level of cleaved-caspase 3 and block phosphorylation of p38/JNK. Overall, this is the first demonstration of TCP damaging to peripheral sensory HCs and SC in organotypic cultures from the postnatal cochlea. Data also showed that TCP exposure induced oxidase stress, cell apoptosis and DNA damage in the HEI-OC1 cells. These findings serve as an important reference for assessing the risk of TCP exposure.

Imbalanced glutamate signaling has been implicated in the development of autism spectrum disorder (ASD). This case-control study was to examine single nucleotide polymorphisms (SNPs) in glutamate receptor and carrier genes and determine their association with childhood ASD in a Chinese Han population. A total of 12 SNPs in genes encoding glutamate receptors (GRM7 and GRM8) and carriers (SLC1A1 and SLC25A12) were examined in 249 autistic children and 353 healthy controls. The Childhood Autism Rating Scale (CARS) and its verbal communication domain were applied to evaluate the severity of the disease and language impairment, respectively. The T allele of rs2292813 in the SLC25A12 gene was significantly associated with an increased risk of ASD (odds ratio (OD) = 1.7, 95

Objective This study aimed to examine the correlation between polymorphisms in vitamin D receptor (VDR) gene and serum vitamin D, and to determine their role in predicting childhood Autism Spectrum Disorder (ASD). Methods Children with ASD and age- and gender- matched healthy controls were recruited from the Chinese Han population. Their serum 25(OH) vitamin D was measured using competitive chemiluminescent immunoassays. The TaqMan probe approach was applied to analyze the common VDR SNPs rs731236 (Taq1), rs11568820 (Cdx2), rs1544410 (BsmI), and rs228570 (FokI). Both linear and logistic regressions were applied in data analysis. Results A total of 269 children with ASD and 320 healthy controls were recruited. Children with ASD had significantly lower levels of serum vitamin D and a significantly higher rate of vitamin D deficiency (< 20 ng/ml) compared to healthy controls (67.7% vs 34.1%). All these examined VDR SNPs were not correlated with serum vitamin D concentrations or vitamin D deficiency. Logistic regression analysis revealed that rs731236 and serum vitamin D were associated with childhood ASD. The area under the receiver operating characteristic (ROC) curve was 0.7285 for serum vitamin D. Children with both T/C genotype of rs731236 and vitamin D deficiency had a higher risk of being diagnosed with ASD. Conclusion All examined common VDR SNPs are not correlated with serum vitamin D concentrations or vitamin D deficiency. The combination of T/C phenotype of rs731236 and vitamin D deficiency are associated with a higher risk of childhood ASD. Vitamin D is a promising target in the prevention and treatment of this disease.

Dysfunctions of the neurotransmitter system are related to the development of many psychological diseases including autism spectrum disorder (ASD). Single nucleotide polymorphisms (SNPs) are correlated with varied susceptibility of ASD and response to treatments. The association between SNPs in genes encoding serotonin and dopamine receptors and childhood ASD was examined in a Chinese Han population. Both autistic children (n = 319) and age-and gender-matched healthy controls (n = 347) were recruited from a local district. Disease severity was evaluated by the childhood autism rating scale (CARS). SNPs of rs6311 and rs6313 in the serotonin receptor HTR2A gene, rs4630328 in the dopamine receptor D2 (DRD2) gene and rs167771 in the DRD3 gene were examined. The CC genotype of rs6311 was significantly associated with an increased risk of ASD (odds ratio (OD) = 1.8 vs TT, 95% confidence interval (CI): 1.2–2.8, P = 0.0085). Carriers of the C allele of rs6311 had a significantly higher risk of childhood ASD (OD =1.3, 95% CI = 1.1–1.7, P = 0.0094). A strong linkage disequilibrium was observed between rs6311 and rs6313 (D′ = 0.93, r2 = 0.86). There were significant correlations between haplotypes (T-A and C-G of rs6311-rs6313) and risk of childhood ASD. In contrast, the frequencies of genotypes and alleles of rs6313, rs4630328 and rs167771 were not significantly different between the case and control groups. All the SNPs examined were not associated with severity of the disease. Our study demonstrates that certain SNPs in the HTR2A gene, but not the DRD2 and DRD3, are associated with susceptibility to childhood ASD.

Abstract Background Little is known about the signaling mechanisms involved in arsenic tolerance or detoxification, although the water channel protein aquaporin-9 (AQP9) and components of the mitogen-activated protein kinase (MAPK) pathway have putative roles. Elucidation of the mechanisms of resistance in mammalian cells would be helpful in developing effective, arsenic-based therapeutic strategies. Methods The association between AQP9 and arsenic accumulation and tolerance was investigated in arsenic-sensitive human liver hepatocellular cells (HepG2) and arsenic-resistant HepG2 (AsHepG2) cells. Results The IC50 value for arsenic of AsHepG2 cells (15.59 µM) was significantly higher than that of HepG2 cells (7.33 µM; Ρ < 0.05), and AsHepG2 cells accumulated significantly low levels of arsenic after treatment with sodium arsenite (NaAsO2; Ρ < 0.01). Arsenic accumulation in AsHepG2 cells reached a plateau 6 h after treatment, while in HepG2 cells it continued to increase throughout the experimental period. Additionally, intracellular arsenic accumulation in AQP9-overexpressing AsHepG2 cells significantly increased within 10 h of treatment, whereas in HepG2 cells it increased throughout the experimental period. The level of AQP9 protein in AsHepG2 cells decreased in a concentration-dependent manner, but was not markedly different in HepG2 cells. Furthermore, after NaAsO2 treatment the level of phosphorylated AQP9 and p38 was significantly increased with time in the two cell lines. Partial inhibition of p38 activity by the specific inhibitor SB203580 did not significantly affect AQP9 protein expression or phosphorylation. Conclusion AQP9 expression and its state of phosphorylation are closely related to arsenic uptake and may regulate cellular arsenic tolerance by reducing its uptake rate. p38 may have a limited role in the regulation of AQP9 phosphorylation in AsHepG2 cells.

Objective Genetic factors play an important role in the development of autism spectrum disorder (ASD). This case-control study was to determine the association between childhood ASD and single nucleotide polymorphisms (SNPs) rs3746599 in the DUSP15 gene, rs7794745 in the CNTNAP2 gene, and rs251379 in the PCDHA gene in a Chinese Han population. Methods Genotypes of SNPs were examined in DNA extracted from blood cells from 201 children with ASD and 200 healthy controls. The Children Autism Rating Scale (CARS) was applied to evaluate the severity of the disease and language impairment. The relationship between SNPs and the risk of ASD or the severity of the disease was determined by logistic regression and one-way ANOVA. Results The genotype G/G of rs3746599 in the DUSP15 gene was significantly associated with a decreased risk of ASD (odds ratio (OR) = 0.65, 95% confidence interval (CI): 0.42-0.99, P = 0.0449). The T allele of rs7794745 in the CNTNAP2 gene was associated with an increased risk of ASD (OR = 1.34, 95% CI: 1.01-1.77, P = 0.0435). The SNP rs251379 was not associated with ASD. Though none of the SNPs examined were associated with ASD severity, rs7794745 was associated with severity of language impairment. Conclusions Our findings suggest that both rs3746599 in the DUSP15 gene and rs7794745 in the CNTNAP2 gene are associated with risk of childhood ASD, and rs7794745 is also related to the severity of language impairment in autistic children from a Chinese Han population.

Vitamin D deficiency has been implicated as a risk factor for autism spectrum disorder (ASD). This case-controlled study was to determine the association between single nucleotide polymorphisms (SNPs) in genes encoding vitamin D metabolism related enzymes and childhood ASD in a Chinese Han population. Both autistic children and age-and gender-matched healthy controls were recruited from September 2012-November 2017. The severity of ASD was evaluated by the childhood autism rating scale (CARS). Taqman probe based real-time PCR was applied to examine genotypes. The association between SNPs and the risk of ASD or the disease severity was examined through the logistic regression. This study recruited 249 children with ASD and 353 healthy controls. The G/A genotype (P = 0.0112) or the G allele (P = 0.0117) of CYP24A1 rs17219315, and the G/A genotype of CYP27B1 rs4646536 (P = 0.0341) were significantly associated with an increased risk of ASD. In addition, multivariate analysis found that A allele of both CYP2R1 rs12794714 (P = 0.0159) and CYP27B1 rs4646536 (P = 0.0268) were significantly associated with the severity of ASD. Genetic polymorphisms in vitamin D metabolism related enzymes are associated with the risk of childhood ASD and the severity of the disease.

Background It is inconclusive whether children with autism spectrum disorder (ASD) experience a deficit in facial emotion recognition. The dopaminergic pathway has been implicated in the pathogenesis of ASD. This study was aimed at determining facial emotion recognition and its correlation with polymorphisms in the dopaminergic pathway genes in children with ASD. Methods Facial emotion recognition was examined in 98 children with ASD and 60 age- and gender-matched healthy controls. The severity of ASD was evaluated using the Childhood Autism Rating Scale (CARS). DNA from blood cells was used to analyze the genotypes of single-nucleotide polymorphisms (SNPs) in dopaminergic pathway genes. SNPs of DBH rs1611115, DDC rs6592961, DRD1 rs251937, DRD2 rs4630328, and DRD3 rs167771 were analyzed. Results Children with ASD took a significantly longer time to recognize all facial emotions, and their interpretations were less accurate for anger at low intensity and fear at both low and high intensities. The severity of the disease was associated with significant delays in recognition of all facial emotions and with a decrease in accuracy in recognition of happiness and anger at low intensity. Accuracy in recognizing fear at high intensity and sadness at low intensity was associated with rs251937 and rs4630328, respectively, in children with ASD. Multivariate logistic regression analysis revealed that SNP rs167771, response time for the recognition of happiness, sadness and fear, and accuracy in recognition of anger and fear were all associated with the risk of childhood ASD. Conclusions Children with ASD experience a deficit in facial emotion recognition. Certain SNPs in the dopaminergic pathway genes are associated with accuracy in recognizing selective facial emotions in children with ASD.

Abstract Background: Dysfunction of glutamate signaling has been implicated in the etiology of autism spectrum disorder (ASD). This case-control study was to examine the association between childhood ASD and single nucleotide polymorphisms (SNPs) in genes of the glutamate signaling pathway in a Chinese Han population.Methods: A total of 12 SNPs in the SLC1A1, SLC25A12, GRM7 and GRM8 genes were examined. The Children Autism Rating Scale (CARS) was applied to evaluate the severity of the disease. The relationship between SNPs and the risk of ASD or the severity of the disease was determined by logistic regression.Results: The T allele of rs2292813 in the SLC25A12 gene was significantly associated with an increased risk of ASD (odds ratio (OD) =1.7, 95% confidence interval (CI): 1.1-2.6, P=0.0107). Other examined SNPs were not associated with the risk of ASD. None of the SNPs examined were associated with the severity of ASD.Conclusions: Our findings support the involvement of SNPs in the SLC25A12 gene, but not SNPs in the SLC1A1, GRM7 and DRM8 genes, in the development of childhood ASD in the Chinese Han population.

Previous studies have revealed that long noncoding RNA (lncRNA) and microRNA play a crucial role in autism, which is a childhood neurodevelopmental disorder with complicated genetic origins. Hence, the study concerns whether lncRNA C21orf121/bone morphogenetic proteins 2 (BMP2)/miR-140-5p gene network affects directed differentiation of stem cells from human exfoliated deciduous teeth (SHED) to neuronal cells in rats with autism. Autism models were successfully established. The neuron cells that differentiated from SHED cell were identified. The expression of lncRNA C21orf121, miR-140-5p, BMP2, Nestin, βIII-tubulin, and microtubule-associated protein 2 (MAP2) and the expression of neuron-specific enolase (NSE) were examined. Besides, the gap junction (GJ) function of SHED, the intracellular free Ca 2+ concentration, and the social behavior and repetitive stereotyped movements of rats in autism were detected. The target relationship between lncRNA C21orf121 and miR-140-5p and that between miR-140-5p and BMP2 were also verified. Firstly, we successfully isolated SHED and identified the differentiated neurons of SHED. Besides, the expression of BMP2, MAP2, Nestin, βIII-tubulin, NSE positive rate, GJ function, and intracellular free Ca 2+ concentration were increased with the upregulation of C21orf121 and downregulation of miR-140-5p, and accumulated time of repetitive stereotyped movements decreased and the frequency of social behavior increased. The results indicate that lncRNA C21orf121 as a competing endogenous RNA competes with BMP2 binding to miR-140-5p, thereby promoting SHED to differentiate into neuronal cells via upregulating BMP2 expression.

Genetic variants have been implicated in the development of autism spectrum disorder (ASD). Recent studies suggest that solute carriers (SLCs) may play a role in the etiology of ASD. This purpose of this study was to determine the association between single nucleotide polymorphisms (SNPs) in SLC19A1 and SLC25A12 genes with childhood ASD in a Chinese Han population. A total of 201 autistic children and 200 age- and gender-matched healthy controls were recruited. A TaqMan probe-based real-time PCR approach was used to determine genotypes of SNPs corresponding to rs1023159 and rs1051266 in SLC19A1, and rs2056202 and rs2292813 in SLC25A12. Our results showed that both the T/T genotype of rs1051266 (odds ratio (OR) = 1.85, 95% confidence interval (CI) = 1.06–3.23, P = 0.0301) and the T allele (OR = 1.77, 95% CI = 1.07–2.90, P = 0.0249) of rs2292813 were significantly associated with an increased risk of childhood ASD. In addition, the G-C haplotype of rs1023159-rs1051266 in SCL19A1 (OR = 0.71, 95% CI = 0.51–0.98, P = 0.0389) and C-C haplotype of rs2056202-rs2292813 in SLC25A12 (OR = 0.58, 95% CI = 0.35–0.96, P = 0.0325) were associated with decreased risks of childhood ASD. There was no significant association between genotypes and allele frequencies with the severity of the disease. Our study suggests that these genetic variants of SLC19A1 and SLC25A12 may be associated with risks for childhood ASD.

PURPOSE:Autism spectrum disorder (ASD) is a group of developmental brain disorders caused by genetic and environmental factors. The objective of this study was to investigate whether single nucleotide polymorphisms (SNPs) in genes related to immune function were associated with ASD in Chinese Han children.MATERIALS AND METHODS:A total of 201 children with ASD and 200 age- and gender-matched healthy controls were recruited from September 2012 to June 2106. A TaqMan probe-based approach was used to genotype SNPs corresponding to rs28532698 and rs4301112 in CD157, rs855867 in AIM2, and rs2237126 in JARID2. Case-control and case-only studies were performed to determine the contribution of SNPs to the predisposition of disease and its severity, respectively.RESULTS:Our results revealed that the genotypes and allele frequencies of these SNPs were not significantly associated with childhood ASD and its severity in this population.CONCLUSIONS:Results of our study suggest that these SNPs are not predictors of childhood ASD in the Chinese Han population. The discrepant results suggest the predictor roles of SNPs have to be determined in different ethnic populations due to genetic heterogeneity of ASD.

目的 探讨多巴脱羧酶(dopa decarboxylase,DDC)与多巴胺受体-1(dopamine receptor-1,DRD1)基因单核苷酸多态性(single nucleotide polymorphisms,SNPs)和中国汉族儿童孤独症之间的关系.方法 应用TaqMan探针方法对97名孤独症患儿和100名健康儿童进行DDC基因rs6592961和DRD1基因rs251937单核苷酸多态性的基因型测定.用儿童孤独症评定量表(Children Autism Rating Scale,CARS)评价孤独症患儿临床表型特征.应用x2检验比较不同基因型和等位基因在孤独症病例组和对照组之间的分布情况.结果 ①病例组和对照组儿童的DDC基因rs6592961位点和DRD1基因rs251937位点等位基因频率和基因型分布上差异均无统计学意义(P＞0.05).②孤独症组病情轻中度与重度儿童DDC的rs6592961和DDR1的rs251937位点等位基因频率和基因型分布上差异均无统计学意义(P＞0.05).结论 DDC基因rs6592961位点和DRD1基因rs251937位点单核苷酸多态性可能与中国汉族儿童孤独症的发病无关联.

Genetic factors play an important role in childhood autism. This study is to determine the association of single-nucleotide polymorphisms in dopa decarboxylase (DDC) and dopamine receptor-1 (DRD1) genes with childhood autism, in a Chinese Han population. A total of 211 autistic children and 250 age- and gender-matched healthy controls were recruited. The severity of disease was determined by Children Autism Rating Scale scores. TaqMan Probe by real-time polymerase chain reaction was used to determine genotypes and allele frequencies of single-nucleotide polymorphism rs6592961 in DDC and rs251937 in DRD1. Case-control and case-only studies were respectively performed, to determine the contribution of both single-nucleotide polymorphisms to the predisposition of disease and its severity. Our results showed that there was no significant association of the genotypes and allele frequencies of both single-nucleotide polymorphisms concerning childhood autism and its severity. More studies with larger samples are needed to corroborate their predicting roles.