OBJECTIVE: To assess the association of microribonucleic acid (miRNA) gene polymorphisms with the risk and clinicopathological characteristics of Crohn's disease (CD) and the influence of miRNA gene variants on the response to ustekinumab (UST) treatment among CD patients. METHODS: From January 2018 to February 2025, 312 patients diagnosed with CD and 527 gender- and age-matched normal controls were selected as the study subjects at the Department of Gastroenterology of the Second Affiliated Hospital of Wenzhou Medical University. Genotypes of miR-155 (rs767649), miR-21 (rs13137), miR-124 (rs531564) and miR-146a (rs57095329, rs2431697) were determined with multiplex polymerase chain reaction-ligase detection reaction (PCR-LDR) technique. The patients were divided into different subgroups according to the Montreal Classification Criteria for CD. Harvey-Bradshaw index (HBI) and simplified endoscopic score for CD were respectively applied to assess the clinical and endoscopic disease activity of CD. Unconditional logistic regression model was employed to analyze the distribution of miRNA gene polymorphisms between the two groups, as well as their influence on the clinicopathological characteristics of CD patients. Among them, 185 CD patients received first-line UST treatment, with the first sufficient dose of UST (6 mg/kg) administered intravenously. Based on the changes in HBI at week 8, the response of patients to UST treatment was evaluated. Unconditional logistic regression model was employed to analyze the distribution of miRNA gene polymorphisms between clinically responsive group (the decline of HBI ≥ 3 scores compared to week 0) and non-responsive group. All of the P values were adjusted by Bonferroni correction. This study has been approved by the Medical Ethics Committee of the Second Affiliated Hospital of Wenzhou Medical University (Ethics No.: 2025-K-12-01). RESULTS: No significant difference was found in the distribution of miRNA gene polymorphisms between the two groups (all P > 0.05). The variant genotype (TC+CC) of rs2431697 was more common among patients with terminal ileal-type and ileocolic-type CD than those with the colonic-type CD (OR = 4.98, 95%CI: 1.49~16.68, P = 0.009, adjusted P = 0.045). However, the opposite conclusion was drawn for the homozygous variant genotype (TT) of rs13137 and variant genotype (GC+CC) of rs531564 (OR = 0.37, 95%CI: 0.18~0.76, P = 0.007, adjusted P = 0.035; OR = 0.36, 95%CI: 0.18~0.73, P = 0.004, adjusted P = 0.020). Compared to patients with non-stricturing and penetrating CD, the variant genotype (AG+GG) and variant allele (G) of rs57095329 were more common in those with stricturing and penetrating CD (OR = 4.06, 95%CI: 2.46~6.71, P < 0.001, adjusted P < 0.005; OR = 3.12, 95%CI: 2.06~4.73, P < 0.001, adjusted P < 0.005). However, the frequencies of variant genotype (AT+TT) and variant allele (T) of rs13137 were lower among patients with stricturing and penetrating CD than in those without (OR = 0.25, 95%CI: 0.15~0.41, P < 0.001, adjusted P < 0.005; OR = 0.45, 95%CI: 0.33~0.63, P < 0.001, adjusted P < 0.005). Additionally, the variant genotype (AG+GG) and variant allele (G) of rs57095329 were more common among those with moderately to severely endoscopic activity than those with mildly endoscopic activity (OR = 2.01, 95%CI: 1.19~3.42, P = 0.009, adjusted P = 0.045; OR = 2.04, 95%CI: 1.28~3.25, P = 0.003, adjusted P = 0.015). In total 117 cases had shown clinical response by week 8, while 68 cases showed no response. Compared with t he clinically non-responsive group, the variant genotype (TC+CC) and variant allele (C) of rs2431697 were more common in the clinically responsive group (OR = 3.86, 95%CI: 1.80~8.32, P = 0.001, adjusted P = 0.005; OR = 2.60, 95%CI: 1.34~5.06, P = 0.005, adjusted P = 0.025). However, the variant genotype (TA+AA) of rs767649 was less frequent in the clinically responsive group than the non-responsive group (OR = 0.40, 95%CI: 0.21~0.74, P = 0.004, adjusted P = 0.020). The same conclusion was drawn for the variant genotype (AT+TT) and variant allele (T) of rs13137 when the clinically responsive group was compared with the non-responsive group (OR = 0.30, 95%CI: 0.14~0.63, P = 0.002, adjusted P = 0.010; OR = 0.54, 95%CI: 0.35~0.82, P = 0.005, adjusted P = 0.025). CONCLUSION Genetic polymorphisms of miRNAs are not associated with the risk of developing CD. The miR-146a (rs57095329) variant may increase the endoscopic activity of CD and the risk for stenosis or penetration. However, the miR-146a (rs2431697) variant may increase the risk of ileal involvement. The miR-21 (rs13137) variant may reduce the risk of ileal involvement and the risk of stenosis or penetration. The miR-124 (rs531564) variant may reduce the risk of ileal involvement. Among patients receiving UST treatment, the miR-146a (rs2431697) variant may increase the clinical response by week 8. However, both the miR-155 (rs767649) and miR-21 (rs13137) variants may decrease the clinical response by week 8.
Humans ; MicroRNAs/genetics* ; Crohn Disease/pathology* ; Male ; Female ; Adult ; Polymorphism, Single Nucleotide ; Middle Aged ; Asian People/genetics* ; Genetic Predisposition to Disease ; Genotype ; Young Adult ; Case-Control Studies ; Adolescent ; East Asian People

OBJECTIVES: The major histocompatibility complex class I chain-related gene A (MICA), a component of the human leukocyte antigen (HLA) gene complex, is involved in the pathogenesis of various diseases including cancers and autoimmune disorders. Rosacea, a chronic inflammatory skin disease with a complex pathogenesis, potentially influenced by genetic and autoimmune factors. This study aims to investigate the relationship among MICA gene polymorphisms, single nucleotide polymorphisms (SNPs), and susceptibility to rosacea, thereby offering new insights into the disease mechanism. METHODS: Peripheral blood DNA samples were collected from 84 patients with rosacea (rosacea group) and 223 healthy volunteers (control group) who visited the Dermatology Outpatient Department of Xiangya Hospital of Central South University between November 2017 and November 2019. MICA genotyping was performed using polymerase chain reaction-sequencing-based typing (PCR-SBT) and the next-generation sequencing (NGS), and the accuracy of the 2 methods was compared. The frequency distributions of MICA alleles between the 2 groups were analyzed. Amino acid clustering and SNP site analyses were conducted to identify haplotype-linked SNPs and to classify MICA polymorphic variants. Distribution differences of these classifications between groups were also examined. RESULTS: Blood tests in rosacea patients showed mildly elevated, with no significant changes in lymphocyte counts. Both PCR-SBT and NGS accurately identified MICA alleles. The most common alleles in the rosacea group were MICA*010:01, MICA*008:04, and MICA*019:01. The frequencies of MICA*002:01 and MICA*027 were significantly lower in the rosacea group compared to controls (6.55% vs 18.16% and 1.19% vs 5.38%, respectively), while and MICA*010:01 were significantly higher (7.74% vs 3.36% and 31.55% vs 18.61%, respectively; all P<0.05). Five short tandem repeat (STR) alleles were identified. Frequencies of MICA-A4 and MICA-A9 were lower in the rosacea group than in the control group (16.07% vs 23.32% and 7.74% vs 17.26%, respectively), whereas MICA-A6 was higher (10.12% vs 4.03%; all P<0.05). Clustering and SNP analysis identified 6 linked SNP sites, classifying MICA variants into Type I (C₃₆+M₁₂₉+K₁₇₃+G₂₀₆+W₂₁₀+S₂₁₅) and Type II (Y₃₆+V₁₂₉+E₁₇₃+S₂₀₆+R₂₁₀+T₂₁₅). Type I MICA variants were significantly associated with rosacea susceptibility. CONCLUSIONS MICA gene polymorphisms are associated with susceptibility to rosacea, and there are 6 linked SNP sites within the MICA gene. Based on this, MICA polymorphic variants are classified into Type I and Type II, with Type I being more closely associated with disease development of rosacea.
Humans ; Polymorphism, Single Nucleotide ; Histocompatibility Antigens Class I/genetics* ; Rosacea/genetics* ; Genetic Predisposition to Disease/genetics* ; Female ; Male ; Adult ; Middle Aged ; Genotype ; Alleles ; Gene Frequency ; Haplotypes ; Case-Control Studies ; Aged ; High-Throughput Nucleotide Sequencing

OBJECTIVES: The gut microbiota plays a crucial role in the pathophysiology of various types of diabetes. However, the causal relationship between them has yet to be systematically elucidated. This study aims to explore the potential causal associations between gut microbiota and diabetes using a two-sample Mendelian randomization (MR) analysis, based on multiple taxonomic levels. METHODS: Eligible instrumental variables were extracted from the selected genome-wide association study (GWAS) data on gut microbiota. These were combined with GWAS datasets on type 1 diabetes (T1D), type 2 diabetes (T2D), and gestational diabetes mellitus (GDM) to conduct forward MR analysis, sensitivity analysis, reverse MR analysis, and validation of significant estimates. Microbial taxa with causal effects on T1D, T2D, and GDM were identified based on a comprehensive assessment of all analytical stages. RESULTS: A total of 2 179, 2 176, and 2 166 single nucleotide polymorphisms (SNP) were included in the MR analyses for gut microbiota with T1D, T2D, and GDM, respectively. MR results indicated causal associations between: Six microbial taxa (Eggerthella, Lachnospira, Bacillales, Desulfovibrionales, Parasutterella, and Turicibacter) and T1D; 9 microbial taxa (Verrucomicrobia, Deltaproteobacteria, Actinomycetales, Desulfovibrionale, Actinomycetaceae, Desulfovibrionaceae, Actinomyces, Alcaligenaceae, and Lachnospiraceae NC2004 group) and T2D; 10 microbial taxa (Betaproteobacteria, Coprobacter, Ruminococcus2, Tenericutes, Clostridia, Methanobacteria, Mollicutes, Methanobacteriales, Methanobacteriaceae, and Methanobrevibacter) and GDM. CONCLUSIONS This study identified specific gut microbial taxa that may significantly increase or decrease the risk of developing diabetes. Some findings were fully replicated in independent validation datasets. However, the underlying biological mechanisms of these causal relationships warrant further investigation through mechanistic studies and population-based research.
Gastrointestinal Microbiome/genetics* ; Humans ; Mendelian Randomization Analysis ; Genome-Wide Association Study ; Diabetes Mellitus, Type 2/genetics* ; Diabetes Mellitus, Type 1/genetics* ; Female ; Polymorphism, Single Nucleotide ; Diabetes, Gestational/genetics* ; Pregnancy

OBJECTIVES: Keloids are fibrotic skin disorders characterized by excessive collagen deposition and a high recurrence rate, closely associated with inflammatory mediators. However, existing epidemiological studies are limited by confounding factors and reverse causality, making it difficult to establish causation. This study aims to investigate the causal relationship between circulating cytokines and keloids using Mendelian randomization analysis. METHODS: Significant single nucleotide polymorphisms (SNPs) associated with circulating cytokines (exposures) and keloids (outcomes) were extracted from genome-wide association study (GWAS) summary datasets. Eligible SNPs were selected as instrumental variables (IVs). Exposure data were derived from a cytokine GWAS including 8 293 Finnish participants, and outcome data from a keloid GWAS based on the UK Biobank. The inverse-variance weighted (IVW) method served as the primary analytical approach to estimate causal effects, supplemented by weighted median (WME), MR-Egger regression, and other sensitivity analyses. Horizontal pleiotropy was assessed using MR-Egger regression and the MR pleiotropy residual sum and outlier (MR-PRESSO) test, while Cochran's Q test evaluated heterogeneity. Leave-one-out analysis was used to verify robustness and consistency. A reverse MR analysis was also conducted, with keloid as the exposure and cytokines as outcomes, to rule out reverse causation. RESULTS: IVW analysis identified significant positive causal associations between two cytokines and keloids-macrophage migration inhibitory factor (MIF) [odds ratio (OR)=2.081, 95% confidence interval (CI) 1.219 to 3.552, P=0.007] and monocyte chemoattractant protein-1 (MCP-1) (OR=1.673, 95% CI 1.036 to 2.701, P=0.035). Conversely, stem cell factor (SCF) showed a negative causal relationship with keloids (OR=0.518, 95% CI 0.269 to 0.998, P=0.049). Results from the MR-Egger and weighted median analyses were consistent with IVW findings. No evidence of horizontal pleiotropy was observed (P>0.05). Except for interleukin-6 (P=0.014), no heterogeneity was detected in other cytokines. Leave-one-out analysis further confirmed the robustness of the causal associations. In reverse MR analysis, keloids were causally related only to β-nerve growth factor (beta-NGF) (OR=1.048, 95% CI 1.002 to 1.095, P=0.039), with no heterogeneity or pleiotropy detected in most cytokines (P>0.05). CONCLUSIONS MIF and MCP-1 exhibit positive causal associations with keloid formation, while SCF shows a negative causal relationship. These findings provide new evidence for the causal involvement of inflammatory cytokines in keloid pathogenesis and offer potential molecular targets for developing novel keloid therapies.
Humans ; Keloid/blood* ; Mendelian Randomization Analysis ; Cytokines/genetics* ; Polymorphism, Single Nucleotide ; Genome-Wide Association Study ; Chemokine CCL2/genetics* ; Interleukin-6/genetics* ; Macrophage Migration-Inhibitory Factors/genetics* ; Male ; Stem Cell Factor/blood* ; Female ; Intramolecular Oxidoreductases

OBJECTIVES: To investigate the causal associations between autoimmune diseases and aplastic anemia (AA) using Mendelian randomization analysis. METHODS: Publicly available genome-wide association study (GWAS) data were utilized to obtain single nucleotide polymorphisms (SNPs) associated with autoimmune diseases and AA for analysis. The inverse variance weighted (IVW) method was employed as the primary analytical approach, with MR Egger, Weighted Mode, Weighted Median, and Simple Mode methods serving as complementary analyses. Heterogeneity and pleiotropy analyses were conducted using designated functions, and the robustness of Mendelian randomization results was assessed using leave-one-out analysis. RESULTS: The two-sample Mendelian randomization analysis using the IVW method revealed significant positive causal associations of rheumatoid arthritis (OR=1.094, 95% CI: 1.023-1.170, P=0.009, adjusted P=0.042), systemic lupus erythematosus (OR=1.111, 95% CI: 1.021-1.208, P=0.015, adjusted P=0.036), Hashimoto thyroiditis (OR=1.206, 95% CI: 1.049-1.387, P=0.009, adjusted P=0.029), and Sicca syndrome (OR=1.173, 95% CI: 1.054-1.306, P=0.004, adjusted P=0.035) with AA, which was supported by the results from the Weighted Median method. Sensitivity analyses indicated no evidence of pleiotropy or heterogeneity, and leave-one-out analysis confirmed the robustness of the causal relationships. No direct evidence was found linking Graves' disease, ulcerative colitis, Crohn's disease, autoimmune hepatitis, primary biliary cholangitis, or primary sclerosing cholangitis with AA (P>0.05, adjusted P>0.05), indicating a lack of causal association. Reverse Mendelian randomization results and multiple corrections indicated that AA was not an influencing factor for autoimmune diseases (adjusted P>0.05). CONCLUSIONS Our findings support at the genetic level that rheumatoid arthritis, systemic lupus erythematosus, Hashimoto thyroiditis, and Sicca syndrome are risk factors for AA, and confirm a causal association of the these 4 autoimmune diseases with an increased risk of AA.
Humans ; Mendelian Randomization Analysis ; Anemia, Aplastic/genetics* ; Autoimmune Diseases/complications* ; Polymorphism, Single Nucleotide ; Genome-Wide Association Study ; Arthritis, Rheumatoid/genetics* ; Lupus Erythematosus, Systemic/genetics* ; Genetic Predisposition to Disease

OBJECTIVES: To investigate the association of HOTAIR gene rs920778 single nucleotide polymorphism (SNP) with breast cancer susceptibility and response to HER2-targeted therapy in a Chinese population. METHODS: TaqMan probe-based real-time quantitative PCR was used for genotyping of the rs920778 locus (chr12:54,376,218) in peripheral blood genomic DNA from 287 breast cancer patients and 260 healthy individuals from northern Anhui Province. The genotype (GG, GT and TT) and allele (G/T) distribution frequencies were compared between the two groups to evaluate their association with breast cancer risk. Multivariate logistic regression analysis was conducted to assess the relationship between SNP at this locus and aggressive clinicopathological features (including tumor size, lymph node metastasis, ER/PR/HER2 status, and molecular subtypes) of breast cancer. For the HER2-positive subgroup, the association between rs920778 genotype and responses to dual-targeted therapy (trastuzumab [6 mg/kg q3w]+pertuzumab [420 mg q3w] + docetaxel [75 mg/m²]) was analyzed. The primary endpoints included pathological complete response rate (pCR), objective response rate (ORR), and progression-free survival (PFS). RESULTS: The TT genotype of rs920778 was associated with a significantly increased breast cancer susceptibility (OR=1.54, 95% CI: 1.09-2.19; P=0.017), an advanced tumor stage (P<0.001), lymph node metastasis (P<0.001), and the triple-negative subtype (P<0.001). In HER2-positive patients, TT genotype carriers had a markedly reduced objective response rate to dual HER2-targeted therapy (33.3% vs 89.3%, P=0.001) and a lower pathological complete response rate after neoadjuvant therapy (P=0.018). CONCLUSIONS The TT genotype of HOTAIR rs920778 serves as an independent risk factor for breast cancer susceptibility and aggressive progression in Chinese population and may predict the resistance to HER2-targeted therapies, suggesting its potential as a prognostic biomarker for precision oncology.
Adult ; Aged ; Female ; Humans ; Middle Aged ; Breast Neoplasms/drug therapy* ; Case-Control Studies ; China ; Drug Resistance, Neoplasm/genetics* ; Genetic Predisposition to Disease ; Genotype ; Polymorphism, Single Nucleotide ; Receptor, ErbB-2 ; RNA, Long Noncoding/genetics* ; East Asian People/genetics*

Neuraxial opioids, widely used in obstetric and perioperative pain management, often lead to unwanted itch, reducing patient satisfaction. While the μ-opioid receptor has been implicated in opioid-induced itch, the genetic basis for variable itch incidence remains unknown. This study examined 3616 patients receiving epidural opioids, revealing an itch occurrence of 26.55%, with variations among opioid types and gender. Analysis of the OPRM1 gene identified six single-nucleotide polymorphisms, notably rs1799971 (A118G), that correlated with opioid-induced itch. Mouse models with an equivalent A112G mutation showed reduced neuraxial opioid-induced itch and light touch-evoked itch, mirroring human findings. The 118G allele demonstrated an anti-itch effect without impacting analgesia, addiction, or tolerance, offering insights for risk stratification and potential anti-itch pretreatment strategies.
Receptors, Opioid, mu/genetics* ; Pruritus/chemically induced* ; Humans ; Analgesics, Opioid/administration & dosage* ; Female ; Male ; Animals ; Polymorphism, Single Nucleotide/genetics* ; Adult ; Mice ; Middle Aged

OBJECTIVES: To investigate the effects of methylenetetrahydrofolate reductase (MTHFR) rs1801133 and γ-glutamyl hydrolase (GGH) rs11545078 gene polymorphisms on plasma concentrations and toxicity following high-dose methotrexate (MTX) therapy in children with acute lymphoblastic leukemia (ALL). METHODS: Children with ALL treated at the Xuzhou Children's Hospital of Xuzhou Medical University from January 2021 to April 2024 were selected for this study. Genotypes of MTHFR rs1801133 and GGH rs11545078 were determined using multiplex polymerase chain reaction. MTX plasma concentrations were measured by enzyme-multiplied immunoassay technique, and toxicity was graded according to the Common Terminology Criteria for Adverse Events version 5.0. The relationships between MTHFR rs1801133 and GGH rs11545078 genotypes and both MTX plasma concentrations and associated toxicities were analyzed. RESULTS: In the low-risk ALL group, the MTHFR rs1801133 genotype was associated with increased MTX plasma concentrations at 72 hours (P<0.05). In the intermediate- to high-risk group, the MTHFR rs1801133 genotype was associated with increased MTX plasma concentrations at 48 hours (P<0.05), and the GGH rs11545078 genotype was associated with increased MTX plasma concentrations at 48 hours (P<0.05). In the intermediate- to high-risk group, the MTHFR rs1801133 genotype was associated with the occurrence of reduced hemoglobin (P<0.05), and the GGH rs11545078 genotype was associated with the occurrence of thrombocytopenia (P<0.05). CONCLUSIONS Detection of MTHFR rs1801133 and GGH rs11545078 genotypes can be used to predict increased MTX plasma concentrations and the occurrence of toxic reactions in high-dose MTX treatment of ALL, enabling timely interventions to enhance safety.
Humans ; Methotrexate/toxicity* ; Methylenetetrahydrofolate Reductase (NADPH2)/genetics* ; Precursor Cell Lymphoblastic Leukemia-Lymphoma/blood* ; Male ; Female ; Child ; Child, Preschool ; gamma-Glutamyl Hydrolase/genetics* ; Antimetabolites, Antineoplastic/adverse effects* ; Infant ; Polymorphism, Genetic ; Adolescent ; Genotype ; Polymorphism, Single Nucleotide

OBJECTIVE: To screen the genetic risk factors related to severe hematology adverse effects (AEs) in patients with chronic myeloid leukemia (CML) treated with imatinib (IM), and explore the correlation of single nucleotide polymorphisms (SNPs) in IM drug metabolism and transport pathway gene polymorphism with the risk of severe hematology AEs. METHODS: 172 newly diagnosed Chinese Han patients in CML chronic phase (CML-CP) treated with IM were included and divided into severe hematology AEs group and non-severe hematology AEs group. The demographic characteristics and laboratory test results were compared between the two groups. 11 gene SNP sites in the included subjects were genotyped using SNaPshot multiplex SNPs technique. RESULTS: Compared with non-severe hematology AEs group, the severe hematology AEs group had higher white blood cell (WBC) and EOS% (both P < 0.05), but lower hemoglobin (Hb) and hematocrit (HCT) (both P < 0.01). For rs1045642 of ABCB1 gene, there were significant differences in the distribution of allele frequency and genotype frequency of this loci between severe hematology AEs group and non-severe hematology AEs group (both P < 0.05). Carriers of rs1045642 mutation allele A had an increased risk of severe hematology AEs (OR =2.09, 95% CI : 1.24-3.55, P =0.005). There was a significant difference in the distribution of NR1I2 gene rs3814055 genotype between severe hematology AEs group and non-severe hematology AEs group (P < 0.05). The additive model and recessive model of ABCB1 gene rs1045642 and the recessive model of NR1I2 gene rs3814055 were associated with the increased risk of severe hematology AEs (OR =2.14, 3.28, 5.54, all P < 0.05). CONCLUSION Peripheral blood WBC, EOS%, Hb and HCT in patients with newly diagnosed CML-CP are all related to the risk of severe hematology AEs. ABCB1 gene rs1045642 and NR1I2 gene rs3814055 related to the metabolism and transport pathway of IM are associated with severe hematology AEs after IM treatment in CML-CP patients, and they may be potential molecular markers to predict the risk of severe hematology AEs of CML patients treated by IM.
Humans ; Imatinib Mesylate ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics* ; Polymorphism, Single Nucleotide ; Genotype ; ATP Binding Cassette Transporter, Subfamily B ; Gene Frequency ; Female ; Male ; Middle Aged ; Adult ; Asian People

OBJECTIVE: To explore the correlation between single nucleotide polymorphisms (SNPs) of ARID5B gene and the risk of acute lymphoblastic leukemia (ALL) and minimal residual disease (MRD) in children of Hui and Han nationality in Ningxia. METHODS: In this case-control study, 54 ALL children and control group with matched age, sex and nationality were detected for the polymorphism of ARID5B gene using fluorescence resonance energy transfer technique, and the susceptibility of different ALL genotypes and their correlation with MRD were analyzed. RESULTS: There were no significant differences in genotype and allele frequency of rs10994982, rs7089424, rs10740055, rs7073837, rs4245595 and rs7090445 between the two groups (P >0.05). At the locus of rs10821936, the frequencies of T/T genotype and T allele in ALL group were significantly higher than those in the control group (both P < 0.05). The C/C genotype of ARID5B gene SNP rs10821936 was a risk factor for early MRD positive in ALL children ( P < 0.05). CONCLUSION ARID5B gene SNP rs10821936 is related to the development of childhood ALL and MRD.
Humans ; Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics* ; Polymorphism, Single Nucleotide ; Case-Control Studies ; Neoplasm, Residual/genetics* ; DNA-Binding Proteins/genetics* ; Transcription Factors/genetics* ; Genotype ; Genetic Predisposition to Disease ; Gene Frequency ; Child ; Male ; Female ; Alleles ; Risk Factors ; Child, Preschool