Consensus on laboratory diagnosis of congenital adrenal hyperplasia due to 21 hydroxylase deficiency / 中华医学遗传学杂志

21 hydroxylase deficiency (21-OHD), the most common form of congenital adrenal hyperplasia, is caused by defects in CYP21A2 gene, which encodes the cytochrome P450 oxidase (P450C21) involved in glucocorticoid and mineralocorticoid synthesis. The diagnosis of 21-OHD is based on the comprehensive evaluation of clinical manifestation, biochemical alteration and molecular genetics results. Due to the complex structure of CYP21A2, special techniques are required to perform delicate analysis to avoid the interference of its pseudogene. Recently, the state-of-the-art diagnostic methods were applied to the clinic gradually, including the steroid hormone profiling and third generation sequencing. To standardize the laboratory diagnosis of 21-OHD, this consensus was drafted on the basis of the extensive knowledge, the updated progress and the published consensuses and guidelines worldwide by expert discussion organized by Rare Diseases Group of Pediatric Branch of Chinese Medical Association, Medical Genetics Branch of Chinese Medical Doctor Association, Birth Defect Prevention and Molecular Genetics Branch of China Maternal and Child Health Association. and Molecular Diagnosis Branch of Shanghai Medical Association.

Expert consensus on the genetic diagnosis for Dystrophinopathies / 中华医学遗传学杂志

Dystrophinopathies, including Duchenne muscular dystrophy, Becker muscular dystrophy and dilated cardiomyopathy, are X-linked recessive genetic disorders due to variants of the dystrophin gene, which can seriously affect quality of life and health. Genetic diagnosis plays a crucial role in their diagnosis, treatment, and prevention. How to rationally select and standardize the use of various genetic techniques is a skill that clinicians must acquire. By compiling expertise of experts from the relevant areas and guidelines published home and abroad, this consensus has provided a guidance from the perspective of genetic diagnosis for the selection of genetic techniques, testing strategies, and detection process for dystrophinopathies.

Current Status and Prospects of Screening for Newborn Hereditary Metaboolic Disease / 罕见病研究

Newborn screening is an effective measure for early detection and early treatment of rare genetic diseases. Among the three-level preventive measures to reduce birth defects, newborn screening has a significant preventive effect, and continues to develop with the advancement of new therapies and new technologies. Newborn screening is also relatively more reliable to obtain data on the prevalence of rare diseases. This article introduces the history and current status of neonatal screening for newborn hereditary metabolic disease in China, presents the disease spectrum and prevalence of 7 819 662 cases of neonatal screening by tandem mass spectrometry, and proposes 12 rare diseases as the primary targeting diseases for newborn screening by tandem mass spectrometry in China. At last, the article raises and discusses the issues of requirement for technology development and ethics of newborn screening.

Clinical application of next generation sequencing in molecular diagnosis of intellectual disability/global developmental delay / 中华检验医学杂志

Intellectual disability (ID) is a group of neurodevelopmental disorders with high heterogeneous in both genotypes and phenotypes and its definitive diagnosis is increasingly dependent ongenome-wide molecular diagnostics.Based on next generation sequencing(NGS), panel sequencing, whole exome sequencing (WES) and even whole genome sequencing are well applied to the molecular diagnosis of ID. Based on these, we recommend WES, especially trio-WES as the preferred detection method. NGS data analysis and reanalysis for ID have clinical significance for diagnosis, and can detect small scale variation and copy number variation in the genome reliably. Therefore, it has the potential to become the next recommended molecular diagnostic toolfor ID.

Pseudodeficiency alleles affect the newborn screening of glycogen storage disease typeⅡ / 中华检验医学杂志

Objective To investigate the effect of pseudodeficiency alleles on the newborn screening of glycogen storage disease typeⅡ(GSDⅡ) by using afluorometric enzymatic assay to determine acidα-glucosidase (GAA) activity in dried blood spot (DBS). Methods A total of 30507 newborns' DBSs, obtained from Newborn Screening Center of Xinhua Hospital Shanghai Jiao Tong University School of Medicine from May to December 2017, were screened for GSDⅡby fluorometric enzymatic assay of GAA activity. The suspected positive DBSs after the first and second screening were directly analyzed by Sanger sequencing of GAA to confirm the diagnosis. Retrospective analysis of 3172 controls without GSDⅡand 36 GSDⅡpatients were conducted to investigate the carrier status of pseudodeficiency alleles. Statistical analysis of frequency of pseudodeficiency alleles were carried out by Chi-square test or Fisher exact probability test. Results GAA activity of 30507 newborns showed a positively skewed distribution. Twenty-nine cases of newborns, suspected to be GSDⅡwere confirmed to be normal with genetic analysis of the original DBSs. Among the 29 suspected positive cases, 24 cases were homozygous for pseudodeficiency alleles c. [1726A/A; 2065A/A], and the other 5 cases were c. [1726G/A; 2065G/A] heterozygote. The frequency of c. 1726G>Ahomozygote in 3172 non-GSDⅡcontrols was 2.08％(66/3172), and c. 1726G>A homozygote occurred in allelic conjunction with c. 2065G>Ahomozygote. Frequency of c. [1726A; 2065A] haplotype in 3172 controls was 3.2％(206/6344). Frequency of c. [1726A/A;2065A/A] homozygote in 36 GSDⅡpatients (16.67％, 6/36) was significantly higher than that in non-GSDⅡcontrols(2.08％, 66/3172) (χ2=34.517, P<0.001). Conclusions Pseudodeficiency alleles show a high frequency in Chinese, which leads to a high false positive rate in the newborns screening of GSDⅡ.The afterword genetic analysis of the original DBS after the GAA activity screening could reduce the effect of pseudodeficiency alleles on the newborns screening of GSDⅡ.

Pseudodeficiency alleles affect the newborn screening of glycogen storage disease typeⅡ / 中华检验医学杂志

Objective@#To investigate the effect of pseudodeficiency alleles on the newborn screening of glycogen storage disease type Ⅱ(GSDⅡ) by using afluorometric enzymatic assay to determine acid α-glucosidase (GAA) activity in dried blood spot (DBS).@*Methods@#A total of 30 507 newborns′ DBSs, obtained from Newborn Screening Center of Xinhua Hospital Shanghai Jiao Tong University School of Medicine from May to December 2017, were screened for GSD Ⅱ by fluorometric enzymatic assay of GAA activity. The suspected positive DBSs after the first and second screening were directly analyzed by Sanger sequencing of GAA to confirm the diagnosis. Retrospective analysis of 3 172 controls without GSDⅡand 36 GSD Ⅱ patients were conducted to investigate the carrier status of pseudodeficiency alleles. Statistical analysis of frequency of pseudodeficiency alleles were carried out by Chi-square test or Fisher exact probability test.@*Results@#GAA activity of 30 507 newborns showed a positively skewed distribution.Twenty-nine cases of newborns, suspected to be GSDⅡwere confirmed to be normal with genetic analysis of the original DBSs. Among the 29 suspected positive cases, 24 cases were homozygous for pseudodeficiency alleles c.[1726A/A; 2065A/A], and the other 5 cases were c.[1726G/A; 2065G/A] heterozygote. The frequency of c.1726G>Ahomozygote in 3 172 non-GSD Ⅱcontrols was 2.08% (66/3 172), and c.1726G>A homozygote occurred in allelic conjunction with c.2065G>Ahomozygote. Frequency of c.[1726A; 2065A] haplotype in 3 172 controls was 3.2%(206/6 344). Frequency of c.[1726A/A; 2065A/A] homozygote in 36 GSDⅡpatients (16.67%, 6/36) was significantly higher than that in non-GSD Ⅱcontrols(2.08%, 66/3 172) (χ2=34.517, P<0.001).@*Conclusions@#Pseudodeficiency alleles show a high frequency in Chinese, which leads to a high false positive rate in the newborns screening of GSDⅡ.The afterword genetic analysis of the original DBS after the GAA activity screening could reduce the effect of pseudodeficiency alleles on the newborns screening of GSDⅡ.

Clinical, molecular genetic analysis, and treatment of 3 children with sitosterolemia / 中华儿科杂志

Objective@#To investigate clinical, molecular genetic characteristics, and treatment outcomes of 3 children with sitosterolemia.@*Methods@#Three cases of children presented with multiple xanthomas during June 2016 to June 2017 were included. The clinical manifestations, laboratory examinations and follow-up data were retrospectively analyzed. DNA was extracted from peripheral blood and analyzed with whole exome sequencing(WES). All the detected variants were confirmed by Sanger sequencing. Plasma plant sterol concentrations were measured by gas chromatography-mass spectrometry.@*Results@#Three cases of children including 1 boy and 2 girls presented with multiple linear and intertriginous xanthomas around skin of the joint areas at the age from 15 months to 6 years and 2 months. Total cholesterol of the 3 cases was elevated to 14.45, 15.47 and 15.85 mmol/L (3.36-6.46), and low density lipoprotein cholesterol was 9.02, 13.54 and 12.47 mmol/L (< 3.36) respectively. Genetic analysis with WES revealed that 2 cases carried compound heterozygous variants in ABCG5 gene, 1 case carried compound heterozygous variants in ABCG8 gene. Two reported variants (p. N437K, p.R446X) and one novel variant (p.Q251X) of ABCG5 were identified in case 2 and 3. Two novel ABCG8 variants (p.R263Q, c.1528_1530delATC) were found in case 1. All these children had extremely high plasma plant sterol levels, thus the diagnosis of sitosterolemia was confirming. The campesterol level was 111.35, 102.86 and 58.91 μmol/L(0.01-10.00), the stigmasterol was 14.97, 29.43 and 17.79 μmol/L (0.10-8.50) and the sitosterol was 231.20, 177.66 and 114.20 μmol/L (1.00-15.00) respectively. The total serum cholesterol levels of three children decreased to nomal after the patients were placed on the low plant sterol/low cholesterol diet. The xanthomas regressed gradually, and almost disappeared after 8 months of treatment in case 1 and 3.@*Conclusions@#Children with sitosterolemia presented with skin xanthomas around the joint areas. The level of total cholesterol, low density lipoprotein cholesterol and plant sterols increased obviously. One novel variant (p.Q251X) of ABCG5 and 2 novel variants (p.R263Q, c.1528_1530delATC) of ABCG8 were identified. Children with sitosterolemia responded well to a low plant sterols/low cholesterol diet.

The clinical and genetic analysis of glycogen storage disease type IV in 5 cases / 临床儿科杂志

Objective To investigate the characteristics of glycogen storage disease type IV (GSD IV) clinically, in laboratory tests and in gene mutation. Methods The clinical manifestations, biochemical indexes, activity of chitotriosidase, and the follow-up of the treatment in 5 cases of GSD IV were analyzed. Results Five patients (3 boys and 2 girls) aged 4 months - 5 years presented hepatosplenomegaly and elevated liver enzyme levels for 2 months at hospital visit. Two patients had motor developmental delay and weakness but their creatine kinase (CK) level were normal. Glycogen storage and liver fibrosis were observed in the liver biopsy in 4 patients. Target sequencing found that all 5 children carried the complex heterozygous mutation of the GBE1 gene with 2 reported mutations(p.R515C,p.R524Q)and 7 novel mutations.The novel mutation contains 5 missense mutations (p.I460T, p.F76S, p.F538V, p.L650R, p.W455R), one insertion mutations (c.141_142insGCGC), and one large fragment deletion (exon 3-7). Therefore, diagnosis of liver type of GSD IV was confirmed in those children. Two patients died of liver cirrhosis. The liver transplantation was performed due to liver cirrhosis in one patient whose chitotriosidase activity increased obviously before transplantation and decreased significantly after the transplantation and liver enzyme levels were returned to normal 4 months after transplantation. In the other two patients their growth and liver enzyme levels were normal;one had not received special treatments while the other was treated with raw corn starch and level of chitotriosidase was normal. Conclusions The clinical manifestations of GSD IV are heterogeneous. Target sequencing can be used for fast and noninvasive diagnosis of GSD IV. Chitotriosidase activity is useful in the prognosis assessment for GSD IV.

Identifying of the ERCC8 gene mutations in a pedigree with Cockayne syndrome / 中华检验医学杂志

Objective To identify the pathogenesis gene mutation of a pedigree with Cockayne syndrome.Methods The peripheral blood samples of the patient and his family members were collected and the genomic DNA was then extracted.Whole exome sequencing(WES)was performed for proband′s DNA.The disease-causing mutations were identified by bioinformatics analysis and pedigree analysis. Meanwhile,the mutations were confirmed by Sanger sequencing.Results Two novel mutations in ERCC8 gene,including c.400-2A >G and c.394_398delATGTA(p.L132fs)were identified in proband.The splicing mutation originated from his father and changed the splice acceptor site AG to GG, thus possibly caused alternative splicing.The c.394_398delATGTA(p.L132fs)frameshifting mutation was inherited from his mother.The proband′s sister also carried the same compound heterozygous mutation and had the same phenotype as proband.Conclusion The pathogenesis ERCC8 gene mutation of this pedigree with Cockayne syndrome was identified by using whole exome sequencing.

Molecular diagnostics of pediatric neurodevelopmental disorders in children / 中华检验医学杂志

Neurodevelopmental disorders(NDD)is a spectrum of disorders characterized with impaired development of the neuropsychological system and /or functional insufficiency in children.The etiology of NDD is still secure though genetic defects are known to be closely associated with development and prognosis of NDD.Recently, the diagnostic yield of NDD is significantly enhanced along with the application of high-throughput genomic analysis including chromosomal microarray analysis(CMA), target sequencing,and whole exome sequencing(WES)in clinical practice.In view of the high genetic heterogeneity and significant expression variability of NDD, it′s preferred to perform an integrated genetic analysis with multiple molecular diagnostic platforms in a standard workflow for patients with NDD.What′s more,an expert consensus and/or technological guideline for molecular diagnostics of NDD generated from large-scale multi-center studies on cohorts of Chinese patients with NDD is crucial for improvement of healthcare for patients with NDD in China.

Clinical phenotypes and genetic study of 2 cases with 22q13 deletion syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To determine the genetic etiology and clinical characteristics of 2 boys featuring development delay (DD).</p><p><b>METHODS</b>Routine chromosomal banding was performed to analyze the karyotypes of the patients and their parents. Single nucleotide polymorphism array (SNP array) analysis was employed to identify pathogenic deletion/duplication of chromosomes, and quantitative real-time PCR (qPCR) was performed to confirm the results.</p><p><b>RESULTS</b>Patient 1 showed a global developmental delay, especially impaired language development, seizures, behavioral problems belonging to the autism spectrum and mild facial dysmorphism. Patient 2 mainly presented with severely delayed speech and moderate intellectual disability, but did not have obvious facial dysmorphism and autistic-like behavior. The diagnosis of 22q13 syndrome was established based on identification of a heterozygous microdeletion at chromosome 22q13.33 in both patients (69 kb and 587 kb, respectively) by the SNP array analysis. Both patients had deletions of SHANK3 and ACR, which are located at the end of 22q. Quantitative real-time PCR verified that the deletion of SHANK3 gene in both patients were de novo in origin.</p><p><b>CONCLUSION</b>Two cases of 22q13 deletion syndrome have been diagnosed by SNP array analysis. Deletion of SHANK3 gene may be the major contributor to the clinical manifestations of the patients. SNP array analysis can facilitate discovery of microdeletions, which has played an important role in the diagnosis and genetic counseling for the family.</p>

Clinical and gene mutation analysis of three children with late-onset glycogen storage disease type Ⅱ with hypertrophic cardiomyopathy / 中华儿科杂志

Objective@#To investigate the clinical and laboratory features of three children with late-onset type Ⅱ glycogen storage disease(GSD) who presented with hypertrophic cardiomyopathy and to analyze the effect of five mutations identified on the acid-α-glucosidase (GAA) activity and stability.@*Method@#Three cases of children with muscle weakness were included in this study.GAA activity was analyzed in Dried Blood Spot of the patients.DNA was extracted from peripheral blood in all the patients and their parents and subjected to polymerase chain reaction and directly sequencing of GAA gene.Five mutant pcDNA3.1-myc-his-GAA expression plasmids(p.G478R, p.P361L, p.P266S, p.Q323X, p.R672Q) were constructed and transient instantaneously transfected into 293T cells to analyze the enzyme activity and stability of GAA.@*Result@#All the three children had the onset of disease at 3 years or 1.5 years of age.They presented with developmental delay, muscle weakness and hypertrophic cardiomyopathy.GAA activity of 3 patients was 2.65, 3.55 and 1.51 pmol(punch·h)(8.00-98.02)respectively. Genetic analysis found 5 mutations (p.G478R, p. P361L, p. P266S, p. Q323X, p. R672Q), and all of these 3 cases had clinical manifestations and were diagnosed as late-onset type Ⅱ glycogen storage disease.Five mutant pcDNA3.1-myc-his-GAA expression plasmids were transfected into 293T cells.Five mutant enzyme activities were found to be only 9.9%-22.5% of the wild-type enzyme activity and the protein expression of the five mutants was 32.0%-63.9% compared with the wild type.@*Conclusion@#This study reports 3 children with late-onset GSD Ⅱ accompanied by hypertrophic cardiomyopathy and compensatory stage of cardiac function in addition to limb muscle weakness.Five pathogenic mutations were identified, and these 5 mutations result in decreased GAA activity and GAA expression by in vitro functional analysis.

Clinical features and PHKG2 gene mutation analysis of 5 Chinese patients with glycogen storage disease Ⅸc / 临床儿科杂志

Objective To investigate the clinical, laboratory and genetic features of glycogen storage disease(GSD)IXc. Methods Five patients suspected as liver GSD were included in our study. DNA was extracted from peripheral blood of all the patients and diagnoses were made after target sequencing to nearly 2700 disease causing genes. All detected mutations were confirmed in the probands and their parents. Further analysis was based on clinical features, routine laboratory examinations and treatment. Results All the 5 patients manifested with severe hepatomegaly, hypoglycemia, moderately to severely elevated liver enzyme levels, hypertriglyceridemia and growth retardation. Four cases showed poor exercise tolerance but with normal creatine kinase (CK) levels. None of the patients showed liver cirrhosis. Growth velocity and hepatomegaly was improved after the uncooked corn starch treatment was initiated. In the 5 patients, 6 different pathogenic or likely pathogenic mutations in the PHKG2 gene were identified, including one reported mutation (p.E157K) and five novel mutations (p.E56X, p.R185X, c.79_88delinsTCTGGTCG, c.761delC,p.R279C). The p.E157K was the most frequently mutation identified (6/12, 50%). Conclusions The p.E157K mutation is the hot mutation in our small cohort. Main clinical features of our patients include fasting hypoglycemia, impaired liver function,short statures and poor exercise tolerance, without developing liver cirrhosis.

Influence of parental origins to the interpretation of chromosomal microarray based clinical pathogenicity analysis / 中华检验医学杂志

Objective To analyze the influence of validating the parental origin to the interpretation of clinical pathogenicity of total 54 copy number variations(CNV)with different clinical significance in 46 patients undergo chromosomal microarray analysis(CMA).Methods A retrospective study.This study enrolled 46 patients conducted in Department of Pediatric Endocrinology and Genetics of Shanghai Xinhua Hospital during the period of August 2014 to December 2015,involving 54 different CNVs detected by CMA.The parental origin of CNVs was examined by CMA or quantitative real-time polymerase chain reaction.Results Totally 54 different CNVs were found in 46 patients by CMA.Seventeen out of the 54 CNVs were pathogenic variations.After validating the parental origin,14 CNVs were proved de novo mutation,while 3 CNVs have maternal origin including 1q21.1 deletion syndrome,Xq27.3q28 and Xq22.1q22.3 duplications which inherited from maternal X chromosome.CNVs of 1q21.1 deletion syndrome often inherited from parents,and no phenotype appears on mother which may be due to the deactivation mechanism of duplications on mother′s X chromosome.Therefore,these 17 pathogenic variations were still considered to be clinical pathogenic significance after validating the parental origin.Ten out of 54 CNVs were variants of uncertain significance-likely pathogenic.After parental original validation,3 CNVs were proved de novo mutation considering likely pathogenic significance,while 7 CNVs have parental origin still judged to be unknown clinical pathogenicity.Twenty-seven out of 54 CNVs were variants of uncertain significance.After validating the parental origin,only 1 CNV was proved de novo mutation considering likely pathogenic significance,while all the others had parental origin considered to be variations likely benign.Conclusion CNVs reported as likely pathogenic should be validated the parental origin in order to further study their clinical pathogenicity,while variants of uncertain significance can preliminary clear its nature by validating parental origin.

A multi-center clinical study of early predictors and follow-up parameters for girls with rapidly progressive central precocious puberty / 中华内分泌代谢杂志

Objective To study the early diagnostic predictors and key follow-up parameters for girls with rapidly progressive central precocious puberty (RP-CPP). Methods A total of 260 girls with CPP participated in a prospective, nonrandomized, multi-center, nested case control study. After follow-up six months without any therapy, 114 girls were divided into RP-CPP (n=70) and slowly progressive CPP (SP-CPP) (n=44) groups. Results The basal serum LH and insulin-like growth factor Ⅰstandard deviation score (IGF-ⅠSDS) were the important risk factors of RP-CPP (OR 4.04, 1.578), especially the former. The receiver operating characteristic (ROC) curve revealed that the areas under the ROC curve of basal LH and IGF-ⅠSDS were 0.83 and 0.807, respectively. The levels of basal LH and IGF-ⅠSDS were at 0.52 mIU/ml and 0.35 respectively for the accuracy diagnosis of RP-CPP with the maximum Youden indexs. After follow-up for six months, the change levels of height, breast stages, bone age/chronological age ratio, serum LH, uterine and ovarian volume in RP-CPP group were significantly higher than those in SP-CPP group (all P<0.05). Conclusions The level of basal serum LH and IGF-ⅠSDS may be used as the risk predictors for early diagnosis for girls with RP-CPP. The change levels of basal LH, progress rates of gonad and sex character, height, and impaired growth potential seem to be the key follow-up parameters for CPP progress.

The application of chromosomal microarray analysis in genomic diseases / 中华检验医学杂志

Copy number variations in the human genome,one of the causes of complex diseases and genetic diseases,can lead to genomic disorders.As these diseases are difficult to diagnose,it is significantly meaningful to conduct genetic researches and molecular diagnosis.Chromosomal microarray can be used to detect copy number variations on a genome-wide scale.With the advantage of high throughput and resolution,chromosomal microarray is perceived as an important means of identifying copy number variations in genomic disorders.As technology advancements of chromosomal microarray and accumulations of clinical experiences,chromosomal microarray has played a significant role in etiological diagnosis of multiple malformations,mental retardation and autism.

Molecular and prenatal diagnosis of a family with Fanconi anemia by next generation sequencing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To provide prenatal diagnosis for a pregnant woman who had given birth to a child with Fanconi anemia with combined next-generation sequencing (NGS) and Sanger sequencing.</p><p><b>METHODS</b>For the affected child, potential mutations of the FANCA gene were analyzed with NGS. Suspected mutation was verified with Sanger sequencing. For prenatal diagnosis, genomic DNA was extracted from cultured fetal amniotic fluid cells and subjected to analysis of the same mutations.</p><p><b>RESULTS</b>A low-frequency frameshifting mutation c.989_995del7 (p.H330LfsX2, inherited from his father) and a truncating mutation c.3971C>T (p.P1324L, inherited from his mother) have been identified in the affected child and considered to be pathogenic. The two mutations were subsequently verified by Sanger sequencing. Upon prenatal diagnosis, the fetus was found to carry two mutations.</p><p><b>CONCLUSION</b>The combined next-generation sequencing and Sanger sequencing can reduce the time for diagnosis and identify subtypes of Fanconi anemia and the mutational sites, which has enabled reliable prenatal diagnosis of this disease.</p>

Comparison of three methods for the genetic diagnosis of spinal muscular atrophy / 中华检验医学杂志

Objective To evaluate the value of PCR-restriction fragment length polymorphism (PCR-RFLP),real-time PCR and multiplex ligation-dependent probe amplification (MLPA) in the genetic diagnosis of spinal muscular atrophy (SMA) and make laboratory support accessible to clinicians for the molecular diagnosis of SMA.Methods Methodological evaluation.Forty-one suspected SMA cases and 359 control individuals received in Shanghai Children's Medical Centre from March 2013 to June 2014 were detected for the deletion of exon 7 and 8 in the survival motor neuron gene 1 (SMN 1) by PCR-RFLP,realtime PCR and MLPA,respectively.Then the results of the three methods were compared and the benefits and limitations of the three methods were evaluated.Results The result of real-time PCR was in complete agreement with that of MLPA,showing that 29 suspected cases harbored homozygous deletions of SMN1 and 1 case possessed heterozygous deletion.Among the homozygous deletions,27 patients demonstrated absence of exon 7 and 8,and 2 cases demonstrated only the absence of exon 7.Meanwhile,both PCR-RFLP and MLPA analysis showed the same results that only 5 out of 395 control cases carried heterozygous deletion.As for cases without heterozygous deletions,PCR-RFLP demonstrated the same result with real-time PCR and MLPA but it missed all the heterozygous ones.Conclusions PCR-RFLP,the conventional SMA gene diagnosis method,was only capable of detecting homozygous deletion of exon 7 and/or 8 of SMN1,but was not as sensitive as to find out the carriers with heterozygous deletions.MLPA could detect the deletion and quantify the copy numbers of exon 7 and 8 of SMN1,efficiently,while the price was relatively high,which brings challenges for its application in the carrier screening of SMA.Compared with these two methods,realtime PCR with high throughput and low input was a rapid,acourate and economic method for the genetic diagnosis of SMA and carrier screening in large populations.

Pedigree analysis of a child with neonatal diabetes / 临床儿科杂志

10.3969/j.issn.1000-3606.2013.06.019

Diagnosis of an uncertain karyotype and mentally retarded child using the whole genome microarray scanning technique / 临床儿科杂志

Objective To investigate the possibility and feasibility of the whole genome microarray scanning technique in clinical cytogenetic diagnosis of an uncertain karyotype and mentally retarded child. Methods The karyotype analysis of the mental development delayed child was 47, XY+mar. Genomic DNA was extracted from the peripheral blood and the whole genome microarray scanning technique was used to analyze the derivative chromosome. Results The whole genome microar-ray scanning technique indicated the derivative chromosome fragment had originated from 9p13.1-p24.3. Conclusions Com-paring to conventional cytogenetic analysis methods, the whole genome microarray scanning technique is of high resolution, high-throughput and high accuracy, which can detect the submicroscopic chromosomal aberrations and replace the conven-tional karyotype analysis.