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We report a case of fetal diencephalic-mesencephalic junction dysplasia (DMJD) diagnosed prenatally. Prenatal ultrasound at 24 gestational weeks showed that the fetus was small, about the size at 22 weeks' gestation, with short biparietal diameter and enhanced echo at the anterior border of thalamus. Fetal MRI showed short T2 signal shadow in the left choroid plexus, and hemorrhage and midbrain dysplasia were suspected. A pathogenic homozygous mutation variant in protocadherins 12 gene (c.1558C>T) was found in this fetus by whole exome sequencing and both parents carried the same heterozygous variation revealed by Sanger sequencing. All of the above information lead to the diagnosis of fetal DMJD, and the pregnancy was terminated after genetic counseling.
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OBJECTIVE@#To carry out genome-wide copy number variations (CNVs) analysis for a boy with autism by using single nucleotide polymorphism array (SNP array).@*METHODS@#SNP array analysis was conducted for the boy and his parents, and the data was validated by real-time PCR. Correlation between the deleted genes and the phenotype was analyzed by reviewing the literature.@*RESULTS@#The patient was found to carry a terminal deletion of 18q22.3q23 (7.1 Mb), which involved FBXO15, ZNF407, ZADH2, TSHZ1, MBP and ADNP2 genes. No pathogenic CNVs were found in the parents. Comparison of the patient with cases reported in the literature suggested that the ZNF407 gene probably accounts for the autistic phenotype in these patients.@*CONCLUSION@#The autistic phenotype of the patient may be attributed to the 18q deletion, for which ZNF407 may be a critical candidate. SNP array has provided an useful tool for the study of molecular mechanism underlying autism.
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Humanos , Masculino , Trastorno Autístico , Genética , Variaciones en el Número de Copia de ADN , Análisis por Micromatrices , Polimorfismo de Nucleótido SimpleRESUMEN
OBJECTIVE@#To carry out single nucleotide polymorphism (SNP)-based chromosome microarray analysis (CMA) for a boy featuring global developmental delay.@*METHODS@#The SNP array was conducted for the child, and real-time PCR was used to validate its result and identify the origin of pathological copy number variants.@*RESULTS@#SNP array revealed that the patient has carried a de novo 2.5 Mb duplication at 2q22.3q23.3, which encompassed ACVR2A, KIF5C, MBD5, EPC2, LYPD6, LYPD6, MMADHC and ORC4 genes. Literature review suggested that the MBD5 gene from the duplicated region may have predisposed to the global developmental delay shown by the girl.@*CONCLUSION@#The patient's clinical phenotype was consistent to that of 2q23 duplication, for which the MBD5 gene may play a key role. CMA has provided an important tool for the diagnosis of patients with global developmental delay.
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Niño , Femenino , Humanos , Deleción Cromosómica , Cromosomas Humanos Par 2 , Variaciones en el Número de Copia de ADN , Proteínas de Unión al ADN , Genética , Genotipo , Cinesinas , FenotipoRESUMEN
Objective To investigate clinical features of Peutz-Jeghers syndrome(PJS)and genetic change in STK11. Methods Clinical data and genetic change in STK11 gene of four PJS children were retrospectively analyzed.Results Four patients have hyperpigmentation on their lips, buccal mucosa or fingers. Intestinal polyposis was found at different locations of gastrointestinal tract. Polypectomy was performed in four patients and pathological section displayed the muscle fibers of the muscularis mucosae form a dendritic structure. And we found 4 heterozygous mutations (c.582C>A,c.580G>A,c.719C>G and c.879insA)on STK11 gene in these patients.Conclusions The PJS patients have typical clinical features;gene detection is helpful to early diagnosis,and we found a novel mutation(c.879insA) in STK11 gene.
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Objectives To explore the association between the single nucleotide polymorphism (SNP) rs2239669 in makorin ring-finger protein 3 (MKRN3) gene and the susceptibility to central precocious puberty (CPP). Methods A case-control study including 246 children with CPP and 269 healthy children was performed.The genotype and MKRN3 expression levels of patients were analyzed by PCR-HRM and RT-PCR,respectively. Results SNP rs2239669 genotype (TT,TC,CC) and allele frequencies (T and C) were different between cases and controls,with higher CC genotype in CPP patients. Under recessive model (CC/TT+TC),CC genotype was higher in CPP group and associated with higher risk of CPP (95%CI:1.062-2.143,P=0.021). MKRN3 expression levels were different among patients with different genotypes,of which TT genotype had the highest level followed by TC and CC (0.376±0.094, 0.330±0.068, 0.250±0.072, P=0.041). Conclusions MKRN3 SNP rs2239669 was associated with increased risk of CPP, and patients with TT genotype had higher MKRN3 levels.
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Objective To investigate the clinical manifestations and motor neuron and pancreas homeobox 1 (MNX1) gene mutation features of Currarino syndrome.Methods Microdeletion and microduplication of the patients were detected by chromosomal microarray analysis (CMA),and literature review was performed for the clinical syndrome of Currarino syndrome with similar genotype.Results Two patients with Currarino syndrome were recruited in this study.Patient 1,a 7-day girl,came to hospital because of recurrent vomiting.Physical examinations showed coarse facial features,vision problems,serious abdominal flatulence and anal stenosis.Bowel imaging revealed malrotation of the midgut;and the magnetic resonance imaging (MRI) showed tethered spinal cord and malformation of sacrococcygeal vertebra.A 7.89 Mb deletion in chromosome 7 q36.lq36.3 region including MNX1 gene and a 2.20 Mb duplication in 14q32.33 area was found by using CMA.Patient 2,a 1 year and 3 months girl,came to hospital with global development delay.Clinical examination showed facial dysmorphic,growth retardation,intellectural disability,ptosis in right eye and anal stenosis.This patient had developmental retardation in language and movement.MRI showed spina bifida occulta.And a 15.00 Mb deletion in chromosome 7 q35q36.3 region was found including MNX1 gene.Literature review revealed that deletions in MNX1 gene led to Currarino syndrome with coarse facial features,growth retardation and intellectural disability,and this type of Currarino syndrome had not been reported in China.Conclusions Two cases of Currarino syndrome caused by microdeletion in 7q36 are reported for the first time in China,and this study can help clinicians to have a better understanding of this disease.
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Objective To explore the effect of food improvement on the retention time of nasogastric tube in stroke patients with dysphagia. Methods Sixty cases were assigned to the control group(30 cases) and the experimental group(30 cases) by random digits table method, the control group received routine nasogastric feeding, and the experimental group were given texture modified foods and thickened liquid to try to help them eating through the mouth. The feeding tube was pull out when the person in experimental group was capable of taking texture modified foods and thickened liquid without difficulty,while the tube was pull out when the person in control group was able to eat regular food and drink regular fluids. The retention time of nasogastric tube of two groups was compared. Results The retention time of nasogastric tube was(6.13±2.96)d in the experimental group and(18.93±7.58)d in the control group, there was significant difference (t =-8.162, P<0.01). Conclusions Food improvement can effectively shortenthe retention time of nasogastric tube in stroke patients with dysphagia.
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<p><b>OBJECTIVE</b>To explore the clinical features and genomic abnormality of a patient with Coffin-Siris syndrome.</p><p><b>METHODS</b>Microdeletion and microduplication were detected with chromosomal microarray analysis (CMA) and verified with real-time quantitative PCR.</p><p><b>RESULTS</b>The patient, a 6-month-old boy, featured global development delay, thick eyebrows, low frontal hairline, long eyelash, flat nasal bridge, hypotonia, difficulty in turning over, over stretching of head, and hypoplatic nails. He could not stand stability or actively grasp. He also has characteristics of rickets. Chromosome karyotype of the patient was normal. Genomic analysis has detected a 1.3 Mb deletion in 6q25.3 region encompassing the ARID1B gene. Neither of his parents was found to harbor the same deletion.</p><p><b>CONCLUSION</b>The 6q25.3 microdeletion probably underlies the Coffin-Siris syndrome in this patient, and rickets may be part of its clinical spectrum.</p>
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Objective To investigate the clinical features of a patient diagnosed with Jacobsen syndrome (JBS) and Paris-Trousseau syndrome (PTS) using chromosomal microarray analysis. Method A retrospective analysis including the patients' clinical manifestations, laboratory examination and genetic analysis was carried out and related literature were reviewed. Results A 14 month-old girl with global development retardation was reported. The patient can sit but cannot walk independently. The patient also presented hypsicephaly, ocular hypertelorism, palpebral ptosis, flat nasal bridge, sparse eyebrows, and speech delay. Gesell development scale showed that the patient was global development retarded with a development level of 40 weeks. No o bvious abnormality was found in EEG but the MRI showed cerebral white matter abnormality. This patient was also diagnosed with neonatal thrombocytopenia in other hospital. Genomic CNVs were detected in this girl, and a 15.7Mb loss was found in the 11q23.3q25 region that covers JBS and PTS region. Conclusions Patient diagnosed with JBS and PTS often present with craniofacial abnormalities, cerebral white matter abnormality and neonatal thrombocytopenia. Chromosomal microarray analysis can help diagnosis.
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Objective To compare the efficiency and safety between Aripiprazole and other traditional drugs for Tourette's syndrome treatment.Methods Databases such as China National Knowledge Infrastructure,Wanfang,VIP,China Biology Medicine Disc,PubMed and Web of Science were electronically searched for studies on Aripiprazole for Tourette's syndrome treatment.According to the inclusion and exclusion criteria,studies,extracted data,and assessed quality were screened.Meta-analysis was performed by using Stata 11.0 software.Results Four studies about Aripiprazole for Tourette's syndrome treatment with 396 patients (Aripiprazole group:201 cases;control group:195 cases) were synthetically and quantitatively analyzed.Meta-analysis results showed that Aripiprazole was better than other traditional agents (placebo,Tiapride,Haloperidol) [standardized mean difference (SMD) =0.21,95% CI:0.10-0.32].The subgroup by time of treatment analysis results indicated that Aripiprazole was superior to other drugs in 2 weeks (SMD =0.28,95% CI:0.06-0.50).There was no significant difference in the efficacy between Aripiprazole and other drugs for treatment of Tourette's syndrome in 4 weeks and 8 weeks after treatment (SMD =0.16,0.28;95% CI:-0.05-0.38、-0.20-0.76).The subgroup by matched drugs results suggested that Aripiprazole was better than Tiapride (SMD =0.29,95 % CI:0.15-0.43),but was not significantly different from Haloperidol (SMD =-0.03,95% CI:-0.28-0.22).There was no significant difference in side effects incidence between Aripiprazole and traditional drugs for treatment of Tourette's syndrome (RR =0.83,95 % CI:0.36-1.89).Conclusions Compared with the conventional drugs,Aripiprazole has better therapeutic efficacy in the treatment of Tourette's syndrome in children in 2 weeks.Aripiprazole is better than Tiapride,but equal to Haloperidol in the treatment of Tourette's syndrome.The safety of Aripiprazole needs to be further verified.
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Objective To analyze the clinical features and gene mutation in mthylmalonic acidemia (MMA) accompanied by homocysteinemia (cblC), and review the relevant literatures. Methods The clinical features of 3 cases of MMA diagnosed by gene detection were retrospectively analyzed, and meanwhile the pertinent literatures of pathogenesis of MMA, especially combined with late-onset cblC and its gene detection, were reviewed. Results Patient 1 (26 days old) suffered from intermittent convulsions for 3 days, with isosuccinic acid 175.8 μmol/L, C3/C2 rate 1.363, homocysteine >?65 μmol/L and abnormal EEG. MMACHC gene detection found an exon deficiency (delEXON1), which has not been reported. Patient 2 ( 12 year old) was hospitalized for limb shaking, hyperspasmia and vomiting. His isosuccinic acid level was 334.3 μmol/L, C3/?C2 rate was 0.37, homocysteine >?65 μmol/L, and had abnormal EEG. MMACHC gene detection found the mutations of c.482G?>?A and c.609G?>?A. Patient 3 was hospitalized for intermittent convulsions for 20 days, whose isosuccinic acid, C3/?C2 rate, and homocysteine were increased. MMACHC gene detection found the mutations of c.394C?>?T and c.540del8 and c.540del8 had not been reported. Review of literatures discovered that MMA was combined with epileptic seizure in some patents, which further validate that the mutation in MMACHC gene c.482G?>?A may be related to the late-onset of cblC. Conclusions Gene detection contributes to the diagnosis of MMA; the mutation of MMACHC gene c.482G>A may be related to the late-onset of cblC; delEXON1 and c.540del8 are new mutations which have not been reported.
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Objective To investigate the molecular mechanism of calreticulin ( CRT) transcription induced by HBV and its viral proteins. Methods The human hepatocellular cell line, HepG2, was trans-fected with pHBV1. 3 and eukaryotic expression plasmids of HBV viral proteins, respectively. The expres-sion of CRT was measured after transfection. A reporter plasmid of CRT promoter was constructed to analyze the induction of CRT promoter by pHBV1. 3 and HBV viral proteins. Furthermore, two truncated and one C/EBPα site deficient mutants were constructed to evaluate the regulatory effects of HBx on CRT promoter. Fi-nally, HepG2 cells were transfected with HBx expression plasmids and the cellular localization of C/EBPαwas analyzed. Results In this study, pHBV1. 3 could significantly up-regulate the expression of CRT at mRNA and protein levels as well as enhancing the activity of CRT promoter. Among the seven HBV viral proteins, HBx could enhance the activity of CRT promoter and the expression of CRT at mRNA and protein levels. HBx could not induce the transcription of CRT when the C/EBPα binding site was deleted from the CRT promoter. The expression of HBx could promote the nuclear translocation of C/EBPα. Conclusion HBV and its viral protein HBx could up-regulate the CRT expression at transcriptional level. The transcrip-tional factor C/EBPα played a critical role in HBx-induced transcriptional activation of CRT.
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Objective To investigate the clinical features of paroxysmal kinesigenic dyskinesia (PKD) and the mutation features of its pathogenic gene proline-rich transmenbrane protein 2 (PRRT2). Method The clinical manifestations and genetic tests of one case of PKD were retrospectively analyzed, and the related literatures were reviewed. Results A 10 year and 9 month male patient was recruited. The age of dyskinesias onset was 7 year and 6 month. The descriptions of the attacks were abnormal involuntary movements which were induced by sudden voluntary movements and presented with dystonia. The frequency of the attacks was three to ifve times per day with the duration lasting ten to twenty seconds, and there is no loss of consciousness. Treatment with oxcarbazepine is effective. A heterozygous mutation in PRRT2 gene, c.649_650insC (p. 217fs224X), was found by genetic testing, and the mutation was inherited from the patient’s mother who showed no symptom of PKD. Conclusion The onset age of PKD could be in the childhood and adolescence. The attack is provoked by sudden movements and the duration time is short. Treatment with antiepileptic drug is effective. The test of PRRT2 gene may help diagnosis. Mutation c.649_650insC is the hotspot mutation of the gene.
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Objective To explore the clinical features of lissencephaly and the detection ofLISI gene.MethodsThe characteristic of clinical features, laboratory examination and gene detection in one case of lissencephaly was retrospectively analyzed. Meanwhile, the related literatures were reviewed.ResultsA 5-month-old female child diagnosed with epilepsy 20 days ago was hospitalized for convulsive seizure more than 30 times in 3 days. The manifestations were eyes staring, and turning upward, cyanosis of lips and face, froth at the mouth, extremities rigidity and loss of consciousness, and the symptoms can spontaneously remitted in 2-3 minutes. Laboratory examination showed that peripheral blood white cell count was 13.67×109/L, hemoglobin 108 g/L, red blood cell count 3.90×1012/L, lymphocyte 10.26×109/L; maocardial enzyme and hepatic and renal function were normal; blood ammonia was 23 μmol/L and lactic acid 2.11 mmol/L. Long-range video EEG showed highly arrhythmia, and frequent partial epilepsy, and sometimes secondary generalized epilepsy. Head MRI showed lissencephaly. The child was treated with oral administration of Keppra 27 mg/(kg·day), Topiramate 6.5 mg/(kg·day), currently no seizure. The detection ofLIS1 gene found that heterozygous mutation of c.232delG, which lead to protein shift mutation (p.E78NfsX25). No mutation was found in her parents.ConclusionsChild with lissencephaly may combine with epilepsy which may cause by mutation inLIS1 gene. And there was no information about point mutation of c.232delG inLIS1 gene being reported at home and abroad so far.
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Objective To investigate the association between single nucleotide polymorphism (SNPs) (rs1053005 and rs744166) and expression level of STAT3 gene and the susceptibility to acute lymphoblastic leukemia (ALL) in Chinese children.Methods A case-control study was performed,and 184 children with ALL and 377 healthy children as controls were recruited.The genotypes of 2 SNPs were detected by using polymerase chain reaction-restriction fragment length polymorphism method.And the expression level of STAT3 gene was detected by using real-time PCR;All the data were analyzed by using SPSS 16.0 software.Results (1) In this study,the genotypes (GG,AG,AA) of rs1053005 had a significant difference between the ALL group and control group (x2 =6.737,P =0.034).Compared with control group,the A allele had a higher frequency in ALL group and A allele was a risk factor(x2 =5.853,P =0.016).But,there was no difference in frequency of genotype rs744166 between the 2 groups (x2 =1.866,P =0.393).(2) There was no significant association between genotypes and risk degree among 3 groups (high risk group,medial risk group and standard risk group) (x2 =0.335,P =0.987).(3) The expression level of STAT3 gene in patients with AA genotype was lower than that of the patients with GG genotype (t =4.758,P =0.009);and compared with patients of the standard risk group,high risk patients had a lower expression level of STAT3 gene (t =5.284,P =0.007).Conclusions The polymorphism of SNP rs1053005 was associated with ALL,with A allele being a risk factor;and the expression level of STAT3 gene maybe associated with the risk degree in ALL patients.
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Objectives To explore the clinical features and diagnosis of LMNA-associated congenital muscular dystrophy. Methods The clinical data from a case of muscular dystrophy caused by LMNA gene mutation were retrospectively analyzed. The related literatures were reviewed. Results A 8-month-old female infant suffered from weakness of raising head, eyelid droop, and motor development retardtion. LMNA gene was sequenced for the infant, her parents and the older sister. Heterozygous mutation of c. 94_96 del AAG (p. K 32 del) was found in the infant leading to the diagnosis of LMNA- associated congenital muscular dystrophy. No mutation was found in the infant’s parents and her older sister. The literature review showed that all ofLMNA- associated congenital muscular dystrophy patients had LMNA gene mutation, more than 80% patients mainly presented with weakness of raising head and may accompany with weakness of proximal limb, motor development retardation, and weakness of axial muscle. Conclusions Mutation analysis of LMNA gene is conducive to the diagnosis of congenital muscular dystrophy.
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Objective To investigate the association of single nucleotide polymorphism (rs2295080) inmTOR gene with the susceptibility to acute leukemia (AL) in Chinese children.Methods A case-control study was performed by recruitment of 180 children with AL and 296 healthy children as controls. The genotype of this SNP was detected using PCR-RFLP. The data were analyzed by SPSS19.0.Results There was a signiifcant difference in genotypes in three groups (ALL, AML and con-trol) (P=0.026). And the SNP was associated with AL, with G allele being higher in AL group than that in controls (OR=1.413, 95%CI: 1.050-1.901,P=0.022). In ALL group, G allele was also higher than that in healthy group (OR=1.456, 95%CI: 1.052-2.015, P=0.023). However, no signiifcant association was observed in AML patients (P=0.302). In addition, ALL patients with GG gen-otype were associated with disease severity compared with patients with TT or GT genotype (OR=2.044, 95%CI: 0.569-7.341). ConclusionThe rs2295080 was associated with ALL, with G allele being a risk factor.
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Objective To investigate the clinical features and genetic basis of cryopyrin-associated periodic syndrome (CAPS). Methods The clinical manifestations, laboratory tests, and genetic tests of one case of CAPS were retrospectively analyzed. The related literatures were reviewed. Results A 7 year and eight month old male patient had recurrent fever for 7 years and his whole body was covered with patchy red rash which was itchy and faded with pressure. The limbs and joints were normal. The levels of high-sensitivity C-reactive protein, erythrocyte sedimentation rate, rheumatoid factors were increased. The patient had fundus arteriosclerosis, double conjunctival lesions and nerve deafness on both sides. There was no mutation found in NLRP3 gene coding region, but a heterozygous mutation (-2667G>T) had been found in 5 ' untranslated region. Compared with normal control, the mRNA level of NLRP3 increased 4.2 times and the expressions of IL-1βand IL-18 gene increased 2.2 (P=0.002) and 1.2 times (P>0.05). Conclusions The clinical features of CAPS can be recurrent fever, rash, and joint involved. The oph-thalmologic abnormalities and varying degrees of deafness may occur during the progression. The test of NLRP3 gene may help diagnosis.
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Objective To investigate the association between 2 single nucleotide polymorphisms( SNPs) [rs2243250 in interleukin(IL)- 4 gene and rs1800925 in IL - 13 gene]in Henoch - Schonlein purpura(HSP)and Henoch - Schonlein purpura nephritis(HSPN)in Han Chinese children. The level of IL - 4 and IL - 13 in serum were compared between HSP and HSPN. Methods A case - control study was adopted in this research,and 383 children with HSP or HSPN were recruited in this study,409 normal children served as controls. The genotypes of 2 SNPs were detected by using polymerase chain reaction - restriction fragment length polymorphism(PCR - RFLP),and the serum levels of IL - 4 and IL - 13 in HSP and HSPN patients were detected by using enzyme linked immunosorbent assay (ELISA). All the data were analyzed by SPSS 16. 0 software. Results (1)There was no association(polymorphism of SNP rs2243250 in IL - 4 gene)in HSP group and HSPN group compared with the healthy control group(P ﹥ 0. 05);and the polymorphism of another SNP(rs1800925 in IL - 13 gene)was associated with HSP(P = 0. 037),and the fre-quency of T allele of the study group was higher than that of the healthy control group(P = 0. 027). But there was no difference between the study group(HSP group and HSPN group)and the healthy control group in frequency of TT genotype(P = 0. 132),and there was no association between HSPN group and healthy control group(P = 0. 487);also there was no association between polymorphism of this SNP in HSP group and HSPN group(P = 0. 129).(2)There was an association between polymorphism of IL - 13 gene and IL - 13 level in serum,patients with TT genotype had a higher serum IL - 13 level than any other genotypes(P ﹤ 0. 05),but there was no statistically significant difference in IL - 4 level between TT genotype and other genotypes(P ﹥ 0. 05).(3)There was an association between polymorphism of IL - 13 gene and IL - 13 level in serum patients with HSPN who had a higher level of serum IL - 13 than the patients with HSP( P ﹤ 0. 05),but there was no difference in serum IL - 4 level between HSP group and HSPN group. Conclusions The polymorphism of SNP(rs1800925 in IL - 13 gene)was associated with HSP group,and the poly-morphism of this SNP might affect the level of IL - 13 in serum. The patients with HSPN have a higher level of serum IL -13 than the patients with HSP,and high level of IL -13 may be a risk factor in the progression from HSP to HSPN.
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<p><b>OBJECTIVE</b>To provide guidance for the high-dose methotrexate (HD-MTX) treatment of pediatric acute lymphoblastic leukemia (ALL), and to understand the impact of SLCO1B1c.521T>C (rs4149056) variant on methotrexate (MTX) pharmacokinetics and clinical outcome in children with ALL.</p><p><b>METHOD</b>Eighty-two children with ALL in Division of Hematology of Wuhan Children's Hospital from January 2008 to February 2013 were enrolled. All patients were genotyped for rs4149056 single nucleotide polymorphism (SNP) into wild-type group (TT genotype) and variant group (TC/CC genotype). According to the ALL-BFM 2000 protocol, all patients received intravenous infusion of MTX every ten days at 3 to 5 g/m(2). Leucovorin rescue was performed after 36 hours of the MTX administration and its dose was adjusted according to the MTX plasma concentration at 48 hours. The concentrations of MTX and its metabolite at 24, 48 and 72 h were determined by high performance liquid chromatography with solid phase extraction. Population pharmacokinetic parameters were estimated by the NLME software. The pharmacokinetics, toxicity and leucovorin rescue was compared. The relapse rate within 5 years and event-free survival were followed up.</p><p><b>RESULT</b>Eighty-two pediatric patients were classified into two groups: variant group including 20 TC genotype carriers and one CC genotype carrier, wild-type group included 61 patients with TT genotype. Compared with wild-type group, plasma concentration of MTX at 48 and 72 h increased significantly [48 h: (1.00±1.41) vs.(0.34±0.17) µmol/L, t=2.131, P=0.046; 72 h: (0.31±0.26) vs.(0.08±0.04) µmol/L; t=3.995, P=0.001]. Area under the concentration time curve (AUC48-∝) of MTX significantly increased in variant group [(23.18±19.91) vs.(5.66±2.01) h·µmol/L] (t=4.025, P=0.001). Time above the MTX safety threshold (TC>0.1 µmol/L) increased significantly in variant group [(95.3±22.0) vs.(67.1±7.5) h, t=5.880, P<0.001]. Rescue dosage of leucovorin in variant group was higher than that in wild-type group [(312.7±287.8) vs.(140.6±27.5) mg/m2, t=2.614, P=0.017]. The children carrying rs4149056 C allele suffered from a higher frequency of serious adverse effect [gastrointestinal toxicity: 33% (7/21) vs. 5% (3/61);hepatic toxicity: 24% (5/21) vs. 2% (1/61)]. The difference was statistically significant (χ2=9.275, 8.289, all P<0.05). Hospital stay of variant group was significantly longer than that of wild-type [(4.95±1.43) vs. (4.05±0.22) d, t=2.881, P=0.009]. The relapse rate within 5 years of variant group and wild-type group were 9% (2/21) and 13% (8/61), respectively. There were no significant differences in the event-free survival between the two groups (χ2=0.001, P=0.971).</p><p><b>CONCLUSION</b>The SLCO1B1 c.521T>C variant was an important determinant of MTX pharmacokinetics. An appropriate leucovorin dose raise in variant group was beneficial to reducing the serious toxicity and did not affect the long-term clinical outcome.</p>