Disease spectrum analysis of 1 520 cases with lysosomal storage disorders / 中华实用儿科临床杂志

Objective:To analyze the disease spectrum of lysosomal storage disorders(LSDs) and explore the prevalent distributions of different LSD types in one center in Shanghai.Methods:A retrospective analysis was made.A total of 5 476 suspected LSD patients, including 3 415 males and 2 061 females, with a median age of 4 years(1 day to 72 years), were collected from Xinhua Hospital, Shanghai Jiaotong University School of Medicine from August 2008 to May 2022.The activity of different lysosomal enzymes was detected by fluorescent and biochemical methods.Results:A total of 1 520 patients were diagnosed with LSDs, including 972 males and 548 females, with a median age of 4 years(1 day to 59 years), involving 19 different subtypes.Mucopolysaccharidosis(MPS) was the most common type among LSDs, with a frequency of 45.46%(691/1 520), followed by sphingolipidoses [33.88%(515/1 520)] and glycogen storage disease type Ⅱ [16.05%(244/1 520)] successively.MPS Ⅱ was the most common type in MPS, with a frequency of 45.73%(316/691), followed by MPS ⅣA [22.87%(158/691)]. Niemann-Pick A/B, Gaucher, and Krabbe diseases were common in Sphingolipidoses patients, with frequencies of 37.09%(191/515), 34.37%(177/515), and 10.29%(53/515), respectively.Conclusions:LSDs are common genetic metabolic diseases, especially MPS and sphingolipidoses.Newborn screening for LSDs should be carried out timely so that the patients can be treated early and their prognosis can be improved.

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.

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.

Detection of urine metabolites in patients with inherited metabolic diseases by nuclear magnetic resonance spectroscopy / 中华检验医学杂志

Objective:Nuclear magnetic resonance spectroscopy (NMR) was used to detect the species and content of metabolites in urine of patients with inherited metabolic diseases, and to explore the application value of NMR technology in the diagnosis of inherited metabolic diseases.Methods:Urine samples were collected from 20 patients with inherited metabolic diseases diagnosed in Xinhua Hospital, Shanghai Jiaotong University School of Medicine from March to June 2019, including 9 cases of methylmalonic acidemia (MMA). NMR pulse length-based concentration determination and Gas chromatography mass spectrometry (GC/MS) semi-quantitative method were used to detect the composition of metabolites in urine samples of patients with inherited metabolic diseases, and the levels of abnormal metabolites in the two methods were analyzed.Results:NMR technology can detect the levels of characteristic metabolites significantly increased in the urine of patients with MMA, isovalerinemia, glutaric acidemia, propionic acidemia, 3-methylcrotonyl-CoA carboxylase deficiency, ornithine carbamyltransferase deficiency, Citrin deficiency, Canavan disease, tyrosinemia and lysinuria protein intolerance. The average is 8 times of the upper limit of the reference value, and the highest is 545 times. Compared to GC/MS, NMR technology can detect the levels of various metabolites such as organic acids, amino acids and sugars. In 9 cases of untreated MMA,the median levels of methylmalonic acid and 3-hydroxypropionic acid in NMR [1 800 (180-12 000) and 50 (0-270) mmol/mol Cr] were higher than the reference values (0-31, 0-35). The median levels of methylmalonic acid and methylmalonic acid in GC/MS [136.56 (43.79-518.67) and 4.87 (1.52-7.52)] were higher than the reference values (0-4 and 0-0.7).Conclusions:NMR and GC/MS technologies are specific for the diagnosis of organic acidemia. The primary component detected by GC/MS is organic acid. NMR technology can break through this limitation and measure the level of various metabolites in urine, which provides a more theoretical basis for the diagnosis and research of inherited metabolic disease.

Treatment and follow-up of 82 children with propionic acidemia / 中华围产医学杂志

Objective:To investigate the treatment and prognosis of children with propionic acidemia (PA).Methods:This study involved 82 children with PA treated in the Department of Pediatric Endocrinol-ogy and Genetic Metabolism, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine from December 2002 to June 2020. Clinical data, including manifestations, laboratory test results, treatment strategy, and follow-up data, were summarized and analyzed using t-test or Mann-Whitney U test. Results:(1) Among the 82 cases consisting of 50 (61.0%) boys and 32 (39.0%) girls, 59 (72.0%) were diagnosed after clinical onset; 22 (26.8%) were diagnosed by newborn screening, including eight asymptomatic ones; the other one (1.2%) was asymptomatic but confirmed after the diagnosis of PA in the patient's sibling. The average age at first onset was 4.5 months (2 d-5 years) in 73 subjects, of which 28 (38.4%) were early-onset PA (within three months after birth). (2) Cranial MRI was performed on 26 cases, and abnormality was identified in 19 (73.1%) cases. (3) Hyperlactatemia was found in 16 cases among 30(53.3%) who underwent relevant examination with the average lactic acid level of 3.5 (2.1-4.3) μmol/L, while 35 out of 40 patients (87.5%) had hyperammonemia with an average blood ammonia level of 105.4 (34-907) μmol/L. (4) Among the 28 early-onset PA cases, 16 (57.1%) died, and 12 (42.9%) survived. There was no significant difference in the serum propionylcarnitine level, propionylcarnitine to acetylcarnitine ratio, urine 3-hydroxypropionic acid, or methylcitrate level between the survival and death cases. (5) Genetic mutations were detected in 75 patients (91.5%), among which 26 (34.7%) carried PCCA gene mutations and 48 (64%) with PCCB gene mutations. One patient (1.3%) harbored one known pathogenic mutation in each of the PCCA and PCCB genes. All mutations were inherited from the parents. (6) Followed up to June 2020, 57 (69.5%) patients survived, and 25 (30.5%) died from multiple organ failure secondary to severe acidosis, including 16 early-onset and nine late-onset cases. Conclusions:The primary treatment of PA is dietary control. Most PA patients are diagnosed after clinical onset, but symptoms may recur and even have developmental retardation despite treatment. Some of those diagnosed through newborn screening are asymptomatic after treatment. Newborn screening using tandem mass spectrometry is recommended for early diagnosis and treatment of PA.

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.

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.

Retrospective analysis on clinical data and genetic variations of patients with beta-ketothiolase deficiency / 中华医学遗传学杂志

OBJECTIVE@#To summarize the clinical, biochemical and molecular characteristics of 8 patients with beta-ketothiolase deficiency (BKD).@*METHODS@#Clinical characteristics, biochemical markers detected by tandem mass spectrometry (MS-MS) and gas chromatography-mass spectrometry (GC-MS), and variations of ACAT1 gene of the 8 patients were reviewed.@*RESULTS@#Three patients were diagnosed by newborn screening and were asymptomatic. Five patients showed dyspnea and metabolic acidosis through high risk screening. Blood methylcrotonyl carnitine (C5:1) were 0.43 (0.20-0.89) μmol/L and 3-hydroxyisovaleryl carnitine(C5-OH) were 1.37 (0.98-3.40) μmol/L. Both were significantly higher than those of healthy controls (PG (p.N375S) variant, which accounted for 28.6% of all 14 mutant alleles. Four novel variants, namely c.229delG (p.E77KfsTer10), c.373G>T (p.V125F), c.419T>G (p.L140R) and c.72+1G>A, were discovered. Pathogenicity assessment of two highly conservative missense variants (p.V125F) and (p.L140R) were 0.994 and 1.0 (Scores obtained from PolyPhen2), and PROVEAN scores were -4.652 and -5.399, respectively. c.72+1g>a was suspected (by Human Splicing Finder) to alter the wild type donor motif and most probably affect the splicing.@*CONCLUSION@#Clinicians should consider MS/MS and GC/MS testing for those with unexplained neurological symptoms and metabolic acidosis in order to attain early diagnosis of BKD. Genetic testing should be used to confirm the diagnosis.

Clinical analysis and outcome of patients with c. 482G >A variant of MMACHC gene in cblC type methylmalonic acidemia / 中华内分泌代谢杂志

Objective To explore the clinical manifestations, treatment and outcomes of patients with c. 482G>A ( p. R161Q ) variant of MMACHC gene in cblC type methylmalonic acidemia ( MMA ) . Methods The clinical manifestations, mass spectrometry results, genotypes, treatment and outcomes of 75 patients with cblC type MMAcarryingc.482G>A(p.R161Q)variantwereretrospectivelyanalyzed.Results Ofthe75patients,57(76％) were from newborn screening and one of them had an onset. Among the rest 18 unscreened patients, 2 were diagnosed after their full sisters' or brothers' diagnosis, the others were clinical patients. There were 17 clinical patients, with the medium age of onset 12 years old (10 days～26 years old). 12 late onset patients (70.6％) presented with poor academic performance, memory loss, poor expression, and decreased exercise capacity, while 5 early onset patients (29.4％) presented with convulsion and delay of development. All patients were vitamin B12-responsive. The levels of blood propionylcarnitine, the ratio of propionylcarnitine to acetylcarnitine, urinary methylmalonic acid and methyldecanoic acid, and plasma homocysteine were significantly decreased after treatment (P< 0.01). All patients diagnosed from newborn screening had normal development. However, only 3 clinical patients had a rather normal outcomes and the others remained different levels of intelligence and ( or ) motor dysfunction after treatment. Conclusion The c.482G>A ( p. R161Q) variant of MMACHC gene is associated with late onset cblC type MMA. Patients with this variant have a better response to hydroxycobalamin than other variants. The outcome of patients diagnosed from the newborn screening is good. When symptoms occur, the disability rate is often high. Therefore, newborn screening is a recommended method to prevent this disease.

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.

Comparison of different methods for measuring the phenylalanine concentration of phenylketonuria patients in dried blood spots / 中华检验医学杂志

Objective To compare the phenylalanine(Phe)concentration in the sample of dried blood spot,measured by four different methods:fluorescence assay,tandem mass spectrometry(MS/MS), including MS/MS Derivatized,MS/MS Non-Derivatized and MS/MS-Standard Curve.Methods A total of 204 dried blood spot(DBS)samples of phenylketonuria(PKU)patients from Shanghai Xinhua Hospital were collected in this study.Phe concentration in DBS was measured by fluorescence assay and MS /MS assay,including MS/MS Derivatized, MS/MS Non-Derivatized and MS/MS-Standard Curve.The samples were divided into low, middle and high concentration groups according to Phe concentration, which were under the 360 μmol/L,between 360 and 600 μmol/L,and over 600 μmol/L respectively.The differences among the groups were analyzed by consistency check and non-parametric test.Results The within-day and between-day precisions of MS/MS-Standard Curve assay were 4.0%-7.2%,the recoveries were 93.2%-97.3%.Consistency check showed that less than 8.1%of Phe value were out of the 95%limit of agreement among these four methods.In the low and middle concentration groups,the quartile of Phe value measured by fluorescence assay,MS/MS Standard Curve and MS/MS Derivatized were 176(118,251)μmol/L,174 (94,273)μmol/L,153(94,242)μmol/L; and 540(478,578)μmol/L,485(414,529)μmol/L,466(402,513)μmol/L,respectively.Phe value measured by fluorescence assay was significantly higher than that by MS/MS Standard Curve,the difference was 4.8%-9.0%,(Z=-3.787 to -2.674,P<0.01). Phe value obtained from MS/MS Non-Derivatized was less than that by MS/MS-Standard Curve, the difference was 3.9%-5.2%,(Z=-7.474 to -5.747,P<0.01).In the high concentration group,the quartile of Phe value measured by MS/MS-Standard Curve, MS/MS Derivatized, MS/MS Non-Derivatized and fluorescence assay were 807(695,924)μmol/L,700(575,785)μmol/L,680(623,771)μmol/L and 711(674, 794)μmol/L, respectively.Phe value obtained from MS/MS Standard Curve was significantly higher than those from the other methods and the difference was 10.9% -16.2%,(Z=-4.458 to-4.356,P<0.01).Conclusions The MS/MS Standard Curve assay showed good specificity and accuracy.These four assays displayed good agreement.Although there was difference in measuring the Phe concentration among these methods, they could be used in blood Phe concentration monitoring for PKU patients.

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.

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>

Prenatal diagnosis of methylmalonic acidemia using test of homocysteine and mass spectrometry in amniotic fluid / 中华检验医学杂志

Objective To explore the value of the combination of homocysteine analysis, liquid chromatography tandem mass spectrometry(LC-MS/MS)and gas chromatography mass spectrometry(GC/MS)in the prenatal diagnosis of combined methylmalonic acidemia and homocystinuria(cblC defect)in amniotic fluid.Methods This is a retrospective study of 187 cases of pregnancies that came to our hospital for prenatal diagnosis between 2014/01-2017/03,among which 78 cases′probands were cblC defect patients and 109 cases′probands were not organic academia patients(control group).Amniotic fluid samples from pregnant women were obtained at 16 -24 weeks of gestation.Propionylcarnitine(C3)and acetylcarnitine (C2)were measured by LC-MS/MS, methylmalonic acid and methylcitric acid were analyzed by GC /MS, and homocysteine was determined by fluorescence polarization immunoassay.Some pregnancies received MMACHC gene sequencing with cultured cells from amniotic fluid.Data were analyzed using Mann-Whitney U and Kruskal-Wallis H tests.Results Among those 78 pregnant women whose probands were diagnosed to be cblC defect,24 cases were diagnosed to be cblC defect(positive group)and 54 pregnant women were diagnosed to be negative(negative group).In positive group, levels of homocysteine, C3, C3/C2, methylmalonic acid and methylcitric acid were all significantly higher than their normal reference ranges, negative group and control group(P values are 0.00).Cases that were diagnosed to be cblC defect by MMACHC gene sequencing were all turned out to be positive in the tests of the above metabolites in amniotic fluid.Cases with negative results of the metabolites were all excluded to be cblC defect by gene sequencing. Besides,2 cases of pregnancies were diagnosed to be positive by homocysteine and mass spectrometric analysis while only one mutation were detected by gene sequencing.Conclusions The combination of homocysteine, LC-MS/MS and GC/MS analysis in amniotic fluid turns out to be reliable for prenatal diagnosis of cblC defect,which may further cover the defect of prenatal diagnosis of those pregnancies whose probands′gene mutation is unknown.

Preparation and evaluation of dried blood spots control materials for steroids / 临床儿科杂志

Objective To investigate the preparation method of dry blood spots (DBS) control materials for steroids used for internal quality control by liquid chromatography tandem mass spectrometry (LC-MS/MS). Methods Whole blood was collected and the blood cells and plasma were separated. The blood cells were washed by saline. The activated charcoal was added to the plasma. Standard substance was added to make different concentrations (low, medium, and high) of DBS control materials for steroids. The precision, accuracy, stability, and differences among different blood spots were detected and analyzed by LC-MS/MS. Results The inter-day precision and accuracy of DBS control materials for steroids were 2.4%-7.0% and 102.0%-111.0%, respectively, and the intra-day precision and accuracy were 5.1%-9.8% and 99.0%-114.8% respectively. The DBS control materials for steroids were stored for 5 months, and there was no difference among the different months (P>0.05). The coefficients of variation among different blood spots were small, 3.3%-8.2%. Conclusions The DBS control materials for steroids has good precision, accuracy and stability. The difference among different blood spots is small and meet the requirements of indoor quality control products. They can be used for the internal quality control in steroids detection by LC-MS/MS.

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.

Mass spectrometry combined with gene analysis for prenatal diagnosis of glutaric acidemia type Ⅰ / 中华儿科杂志

Objective@#To investigate the value of amniotic fluid metabolite detection by mass spectrometry combined with gene mutation analysis in the prenatal diagnosis of glutaric acidemia type Ⅰ (GA-Ⅰ).@*Method@#From January 2009 to December 2016, Department of Pediatric Endocrinology and Genetic, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine carried out prenatal diagnosis for 24 cases of pregnant women with GA-Ⅰproband. 24 pregnant women without organic acidemia proband for conventional prenatal diagnosis at the same period were used as the control group. The pregnant women of the two groups had the amniocentesis at 16 to 20 weeks of gestation.The levels of glutaryl carnitine (C5DC) and octanoylcarnitine (C8) in amniotic fluid were detected by tandem mass spectrometry, and the levels of glutaric acid was determined by gas chromatography-mass spectrometry. All the amniotic fluid cells underwent GCDH gene testing.@*Result@#A total of 4 cases of fetuses were diagnosed by gene mutation analysis combined with mass spectrometry detection, the levels of C5DC (1.58(0.89-2.85) μmol/L), C5DC/C8 (19.74(12.40-25.93))and glutaric acid (129.96 (90.09-66.02) mmol/mol Cr) were significantly higher than the upper limit of the reference, of which in one case with the proband only on mutation was detected, and in the amniotic fluid cells also only one mutation was detected, the diagnosis was made according to the significantly increased levels of amniotic fluid C5DC, C5DC/C8 and glutaric acid. Twenty cases of fetuses were identified as non-GA-Ⅰchildren, of whom in 2 cases of proband only one mutation was detected, and also in amniotic fluid cells one mutation was detected, in 2 cases the diagnosis was excluded because the normal levels of C5DC, C5DC/C8 and glutaric acid. There were 2 cases whose levels of C5DC or glutaric acid were slightly higher than the upper limit of the reference, but the diagnosis was excluded according to genetic testing.@*Conclusion@#Prenatal diagnosis cannot be made by gene analysis when the proband mutation is not clear, and it cannot determine whether the fetus is patient when the mass spectrometry detection of amniotic fluid metabolite is mildly abnormal, while mass spectrometry detection of amniotic fluid C5DC, C5DC/C8 and glutaric acid levels combined with GCDH gene analysis can make up the deficiencies, and make the prenatal diagnosis of GA-Ⅰ more reliably.

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.