Genetic analysis of neonates with abnormal isovaleryl carnitine metabolism / 中华实用儿科临床杂志

Objective:To explore the genetic causes of abnormal isovaleryl carnitine (C5) metabolism in newborns.Methods:Retrospective study.The screening and clinical follow-up data of 34 neonates with elevated C5 levels shown by the tandem mass spectrometry test in Children′s Hospital, Zhejiang University School of Medicine from January 2018 to December 2021 were collected.Afterwards, their ethylenediaminetetraacetic acid (EDTA) anticoagulant venous blood was collected to extract genomic DNA.A total of 79 genes related to genetic metabolic diseases, such as ACADSB, IVD and ACADM, were captured by liquid-phase capture technology.High-throughput sequencing and bioinformatics analysis were used to acquire gene variation information and the genes were categorized by American College of Medical Genetics and Genomics classification standard.According to the results of genetic analysis, the newborns with C5 elevation were divided into 3 groups: non-mutation group(11 cases), ACADSB mutation group(16 cases) and IVD mutation group(7 cases). Wilcoxon rank sum test was performed to analyze the difference between these groups. Results:Among 34 neonates, 6 ACADSB variants were detected in 16 cases, and 2 of them [c.461G>A (p.G154E), c.746delC(p.P249Lfs*15)] were novel variants.Eleven IVD variants were detected in 7 cases, and 7 of them [c.118A>G(p.N40D), c.296-10C>G, c.302A>G(p.Y101C), c.537G>A(p.M179I), c.667C>T(p.R223W), c.983A>G(p.K328R), c.1147+ 5G>A] were never reported before.There was no significant difference in the C5 concentration in initial screening among the three groups ( P>0.05). Conclusions:Mutations in ACADSB and IVD genes are the main causes of augmented C5 levels in neonatal screening.For newly discovered genetic variants, functional prediction by multiple bioinformatics analysis software is recommended.And it is also important to carry out clinical follow-up and evaluation.

A multi-center study of biochemical and hotspot gene screening for neonatal genetic metabolic diseases / 中华实用儿科临床杂志

Objective:To investigate the efficiency of biochemical screening and hotspot gene screening in the detection of neonatal inherited metabolic diseases.Methods:This was a prospective multi-center study.The study was carried out on 21 442 neonatal samples collected from 12 hospitals in 10 provinces from November 2020 to November 2021.The results of biochemical screening and hotspot gene screening were analyzed jointly.Biochemical screening methods included glucose-6-phosphate dehydrogenase deficiency enzyme activity assay and neonatal tandem mass spectrometry.Genetic screening analysis involved 135 genes associated with 75 neonatal diseases.Results:Of all the 21 442 neonates enrolled in the study, 21 205 were subject to biochemical screening.A total of 813 cases were positive in the initial screening, and 0.45% of them (95 cases) were diagnosed after recall.All the 21 442 neonates underwent gene screening.About 168 positive cases were detected in the initial screening, and 0.73% (156 cases) of them were confirmed finally.Biochemical and genetic screening improved the detection sensitivity of such diseases as primary carnitine deficiency, neonatal intrahepatic cholestasis caused by citrin deficiency, and 2-methylbutyrylglycinemia.Moreover, biochemical and genetic screening enabled the detection of more diseases, including the common single-gene genetic diseases such as thalassemia and Wilson disease.Conclusions:In neonatal screening, the combination of biochemical screening and gene screening expands the number of diseases detected and improve screening efficiency.

Identification of a de novo missense variant of ARID1B gene in a child with mental retardation / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child with mental retardation.@*METHODS@#The child was subjected to next generation sequencing (NGS). Candidate variant was analyzed with bioinformatic software.@*RESULTS@#NGS revealed that the child has carried a de novo heterozygous c.4035G>C (p.Gln1345His) variant of the ARID1B gene. The variant was unreported previously and may cause instability of the protein structure.@*CONCLUSION@#The de novo missense variant of ARID1B gene may underlie the mental retardation in the child. Above result has enabled genetic counseling and prenatal diagnosis for her family.

Application of Region 4 Stork system in the neonatal screening for very long chain acyl-CoA dehydrogenase deficiency by tandem mass spectrometry / 中华检验医学杂志

Objective:To investigate the application feasibility of Region 4 Stork (R4S) system, an international collaborative newborn screening data platform, combined with cut-off value analysis in the neonatal screening for very long chain acyl-CoA dehydrogenase deficiency (VLCADD) by tandem mass spectrometry (MS/MS).Methods:The retrospective study was performed in 2, 040 072 neonates screened by MS/MS in Neonatal Screening Center of Zhejiang Province, China from October 2013 to July 2018. Nine hundred and ten cases were determined and identified as suspected positive VLCADD neonates by traditional cut-off method of tandem mass spectrometry. The original data of these 910 screened neonates were further analyzed by R4S system. Based on clinical diagnosis and ACADL gene test results, the screening efficiency between two methods was statistically compared.Results:The data of 910 suspected VLCADD-positive cases interpreted by cut-off method were further analyzed by R4S system, and the positive interpretation was reduced to 238 cases (including 9 confirmed positive cases). A total of 16 different mutations were found in ACADL gene sequencing among the confirmed children. The screening false positive rate (FPR) declined from 0.44‰ (901/2 040 072) to 0.11‰ (229/2 040 072), the rate of positive predictive value (PPV) increased from 0.99% (9/910) to 3.78% (9/238), and the specificity increased from 99.96% (2 039 162/2 040 063) to 99.99% (2 039 834/2 040 063). There was a statistically significant difference between cut-off method alone and cut-off method combined R4S system analysis (χ2=393.5, P<0.05). Conclusions:The R4S system combined with cut-off method applied in VLCADD neonatal screening by MS/MS can effectively improve screening performance, reduce false positive rate, and has certain value in clinical application.

Genetic analysis of newborns with abnormal metabolism of 3-hydroxyisovalerylcarnitine / 浙江大学学报·医学版

OBJECTIVE@#To investigate the genetic characterization of 3-hydroxyisovalerylcarnitine (C5-OH) metabolic abnormality in neonates.@*METHODS@#Fifty two newborns with increased C5-OH, C5-OH/C3 and C5-OH/C8 detected by tandem mass spectrometry during neonatal screening were enrolled in the study. Genomic DNA was extracted from the whole blood samples of 52 cases and their parents. Seventy-nine genes associated with genetic and metabolic diseases including , were targeted by liquid capture technique. Variation information of these genes was examined by high-throughput sequencing and bioinformatic analysis, and then was classified based on the American College of Medical Genetics and Genomics (ACMG) standards and guidelines. The genetic types were classified as wild-type, -maternal-mutation, -paternal-mutation and -mutation. Wilcoxon rank-sum test was performed for the increased multiples of C5-OH calculated in neonatal screening.@*RESULTS@#Twenty one variants (14 novel) were identified in 37 cases, 6 variants (5 novel) in 4 cases. The increased multiple of C5-OH calculated in -maternal-mutation and -mutation groups were significantly higher than that in wild-type group (all 0.05).@*CONCLUSIONS@#Mutations on and genes are the major genetic causes for the increased C5-OH in neonates, and maternal single heterozygous mutation can contribute to the moderately to severely increased C5-OH.

Screening for hereditary tyrosinemia and genotype analysis in newborns / 浙江大学学报·医学版

OBJECTIVE@#To analyze the results of screening for hereditary tyrosinemia (HT) in newborns and its clinical features and genotype.@*METHODS@#The HT screening was conducted among 2 188 784 newborns from November 2013 to November 2018. The tyrosine (TYR)/ succinylacetone (SA) levels were detected by tandem mass spectrometry (MS-MS). The clinical characteristics, genetic results and following up data of identified patients were analyzed.@*RESULTS@#The normal ranges (0.5%-95.5%) of TYR and SA were 34.5-280.0 μmol/L and 0.16-2.58 μmol/L, respectively. Three HT cases were confirmed with a detection rate of 1∶729 595. There was 1 case of tyrosinemia type Ⅰ (HTⅠ) (homozygous variations of c.455G>A in gene), 1 case of tyrosinemia type Ⅱ(HTⅡ) (heterozygous variations of c.890G>T and c.408+1G>A in gene), and 1 case of tyrosinemia type Ⅲ (HT Ⅲ) (homozygous variations of c.257T>C in gene). The variations of c.890G>T, c.4081G>A of and c.257T>C of were novel. The positive predictive value of the screening was 3.4%. Case 1 (HTⅠ) with TYR and SA values of 666.9 μmol/L and 3.87 μmol/L respectively, presented cholestasis, mild elevated of liver enzyme and lactic acid, who were although fed with TYR and phenylalanine free milk, but died at 2 months of age. Case 2 (HTⅡ) with higher TYR (625.6 μmol/L) and normal SA at screening, received medical milk treatment; during the 7 months of follow-up the baby showed normal score of Bayley assessment and normal TYR without eye and skin symptoms. Case 3 (HT Ⅲ) with TYR of 1035.3 μmol/L and normal SA at screening; during the 29 months of follow-up the value of TYR fluctuated from 532.1 μmol/L to 1060.3 μmol/L due to irregular medical milk treatment, while the score of Bayley assessment was normal.@*CONCLUSIONS@#HT is rare in the southern Chinese population, and the gene spectrum is scattered. Early treatment with nitisinone is recommended in children with HTⅠ, otherwise the prognosis is poor; the prognosis of children with HTⅡ is good when early treated with special diet; the prognosis of children with HTⅢ needs to be determined with more data.

Preliminary investigation of gender assignment in 46,XY disorders of sex development with severe male undermasculinisation / 中华儿科杂志

Objective@#To explore the feasibility of gender assignment in 46,XY disorders of sex development (DSD) with severe undermasculinisation mainly based on molecular diagnosis.@*Methods@#A retrospective study of 45 patients of 46, XY DSD with severe undermasculinisation were admitted between November 2015 and October 2018 at Children′s Hospital, Zhejiang University School of Medicine. The initial social gender were all female, of whom the external genital manifestations were Prader 0 to 2; the degree of masculinity was scored using external masculinisation score (EMS); the position and development of the gonads were examined by ultrasound, cystoscopy and laparoscopy, also including assessing the development of the Wolffian tube and the Müllerian tube. The level and ratio of testosterone to dihydrotestosterone before and after hCG stimulation were evaluated for the function of Leydig cell and 5α-reductase-2. Gender role scales and sandbox games were used to assess gender role behavior. Genital sensitivity to androgen stimulation was assessed; A panel including 163 genes related to gender development were determined by second-generation sequencing in all 45 patients. Finally, a multidisciplinary team (MDT) makes a gender assignment after a comprehensive analysis mainly based on the molecular etiological diagnosis.@*Results@#Thirty-nine out of 45 patients (87%) had an identifiable genetic etiology, and the remaining 6 (13%) were negative for genetic testing. Forty-five patients had EMS less than or equal to 3 points. Sexual psychological assessment was performed in 39 patients, with male dominance in 24 (62%) and female dominance in 15 (38%). The gender assignment was 23 cases (51%) for male and 19 cases (42%) for female, and 3 cases (7%) were not completely determined.@*Conclusions@#Molecular diagnosis provides a strong basis for appropriate gender assignment of 46, XY DSD children with severe undermasculinisation. Based on molecular diagnosis, each DSD should be analyzed by professional MDT to analyze the clinical symptoms/signs, gonadal development, gonad tumor risk, external genital morphology, sexual psychological assessment, potential fertility opportunities, parental views, Social and cultural factors, etc. make appropriate gender assignment.

A survey for screening situation of glucose-6-phosphate deficiency in Zhejiang province / 临床检验杂志

Objective@#To explore the epidemiological distribution characteristics of glucose-6-phosphate dehydrogenase (G6PD) activity, incidence of G6PD deficiency in neonates and the cut-off values. @*Methods@#About 1.44 million newborns in 10 districts of Zhejiang province from March 2015 to September 2017 were included in this study. Fluorescence analysis was used to determine the G6PD activity in dried blood spots. Those with initial screening positive results were recalled and confirmed by direct ratio of G6PD to 6PGD (6-phosphogluconate dehydrogenase) to confirm the diagnosis. The results were analyzed by using nonparametric and chi-square tests. @*Results@#Significant differences of G6PD levels were found among the groups of different genders, gestational age, birth weight, blood sampling age, blood sampling season and districts (P＜0.01). The male incidence of G6PD deficiency was significantly higher than female incidence. In different regions of Zhejiang province, the highest prevalence was in Lishui (0.38%) and the lowest was in Zhoushan (0.11%), The trend of high prevalence in the south and low prevalence in the north was basically showed. When the cut-off value of G6PD activity ranged from 2.60 to 2.80 U/g Hb, the sensitivity of G6PD deficiency screening for male and female newborns was 100% and the Youden index was the highest (about 0.99). @*Conclusion@#The level of G6PD activity may be relevant to the factors of population group and period. The incidence of G6PD deficiency may be affected by different genders and different regions. The cut-off values for screening may initially set at 2.60 U/g Hb and 2.80 U/g Hb for male and female respectively.

Preliminary application of Region 4 Stork project used in newborn screening by tandem mass spectrometry / 中华检验医学杂志

Objective To investigate the feasibility of Region 4 Stork(R4S)project used for newborn screening by tandem mass spectrometry in China.Methods This retrospective study was performed among 362 822 neonates screened by tandem mass spectrometry from May 2015 to April 2016 in Zhejiang newborn screening center.Infants were grouped by screening result category: 83 true positive cases,360 554 true negative cases and 2 185 false positive cases.Raw data was uploaded into R4S website to perform postanalytical interpretive tools, then results were analyzed with interpretation rules.The comparisons of normal population percentiles were done at five selected percentiles between Zhejiang newborn screening center and R4S project with min-max normalization.Results Compared with cutoff system by using R4S project with interpretation rules,the positive predictive value increased from 3.7%to 8.3%,the specificity increased from 99.40%to 99.75%, and the false positive rate declined from 0.6% to 0.2%. The two cases of true positive hyperprolinemia were reported negative, and one case of β-ketothiolase deficiency was misdiagnosis.Totally 311 638 cases in true negative group were resolved by postanalytical interpretive tools,and the remaining 48 916 cases were excluded with interpretation rules.False positive cases were reduced to 897 cases.Results of percentiles comparison showed that levels of some markers were significantly different between zhejiang newborn screening center and R 4S project.Conclusions R4S project effectively improved the newborn screening performance, whereas leaded to a small number of misdiagnosis and missed diagnosis.Besides,many true negative cases should be excluded with interpretation rules.Optimization should be achieved based on local normal population.(Chin J Lab Med,2018,41:300-304)

Effects of physical and chemical factors in environment for dried blood spot preparation of neonatal screening assay / 临床检验杂志

Objective To investigate the effects of physical and chemical factors in the environment for dried blood sample (DBS) preparation of neonatal screening assay.Methods A total of 60 normal and 120 positive DBS were prepared under control and 10 different conditions.Another 30 normal and 80 positive DBS were prepared under control and 7 different concentration gradients of formaldehyde.The levels of phenylalanine (Phe),glucose-6-phosphate dehydrogenease (G6PD),thyroid stimulating hormone (TSH) and 17α-hydoxyprogesterone (17α-OHP) were tested by time-resolved fluorescence immunoassay or fluorescence assay.Statistical analysis was performed using SPSS 22.0 software.Results Compared with the control group,the results of Phe were not significantly different (P ＞ 0.05) when the samples were dried under the formaldehyde sensitive threshold (4.62 to 6.95 ppm for 18 hours).G6PD levels were significantly lowered when the samples were dried under all the conditions except for fast cold drying (2 to 8 ℃ overnight and formaldehyde condition,0.30 to 0.38 ppm for 4 hours or 0.21 to 0.24 ppm for 18 hours).TSH and 17α-OHP levels were lowered obviously when the samples were dried under the conditions of humidity,UV and formaldehyde condition (TSH:0.32 to 0.52 ppm for 4 hours,0.38 to 0.45 ppm for 18 hours,17α-OHP:4.37 to 4.62 ppm for 4 hours,0.38 to 0.45 ppm for 18 hours).The results of Phe,G6PD,TSH and 17α-OHP were not statistically different with the control group when the samples were dried under the fast cold drying and 2 to 8 ℃ overnight.Conclusion The physical and chemical factors in the environment of DBS preparation should be related to the accuracy of neonatal disease screening closely.The necessary control factors including formaldehyde,ethanol,glacial acetic acid,ultraviolet irradiation,heat,humidity and decoration pollution may exhibit significant effects on the preparation of DBS.Fast cold drying and overnight at 2 to 8 ℃ could be available for DBS preparation.

Analysis of newborn screening for galactosemia and genotype-phenotype of confirmed galatosemia cases / 中华儿科杂志

Objective@#To investigate the prevalence of galactosemia(GAL), and the characteristics of genotype and phenotype of newborns who were confirmed with GAL in newborn screening in Zhejiang province.@*Method@#The number of all live births, newborn screened infants and all clinical data of confirmed newborns with GAL from October 2013 to March 2015 were retrospectively analyzed by reviewing the data of Zhejiang Province screening center database. And the characteristics of genes and the clinical data of GAL cases who were confirmed by correlative gene test and enzyme activity measurement were analyzed.@*Result@#The prevalence of GAL in Zhejiang province was 1/189 857. Among them, there was 1 case confirmed with GAL typeⅠ (prevalence, 1/759 428), with mutations of c. 904+ 1G>T and c. 687G>A, the enzyme activity of galactose-1-phosphate uridyltransferase (GALT) was 56.4% of controls. And there was 1 case of GAL typeⅡ(prevalence, 1/759 428), with mutations of c. 85G>T and c. 502G>A. There were 2 cases confirmed with GAL type Ⅲ(prevalence, 1/379 714), with mutations of c. 505C>T, c. 452G>A, c. 280G>A and c. 925G>A, the enzyme activity of UDP-galactose-4′-epimerase (GALE) were 42% and 38% of controls, respectively. All cases had different abnormal biochemical marks of liver function, and 1 case had combined hyperlactacidemia or hyperammonemia or increase of multiple kinds of amino acids, respectively. The newborn of GAL type Ⅱ had phacoscotasmus before treatment. All the cases were fed with lactose free milk powder, and all the abnormal parameters were improved during following up.@*Conclusion@#The disease of GAL is rare in Zhejiang province, and its genotype distribution is scattered with comparatively mind clinical manifestations, and the cases with early treatment with lactose free milk powder have good prognosis. All cases needed to be treated and followed up for a life-long time. It is recommended that the high risk cases with GAL should be screened as soon as possible.

Studies on PANK2 gene mutations in Chinese patients with Hallervorden-Spatz syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study pantothenate kinase 2 (PANK2) gene mutations in Chinese patients with Hallervorden-Spatz syndrome (HSS).</p><p><b>METHODS</b>PANK2 gene mutations were detected by PCR, DNA sequence analyses, restriction enzyme digestion and PCR-single strand conformation polymorphism in 5 patients, 3 unaffected family members and 51 unrelated healthy persons.</p><p><b>RESULTS</b>Novel compound heterozygous PANK2 gene mutations, A803G and T1172A, in exons 3 and 5, respectively, were found in one patient. At the same time, 3 types of single nucleotide polymorphisms, -38 t>a in 5'-UTR, IVS1+42 c>a and G77C in exon 1, were confirmed; among them, -38 t>a, IVS1+42 c>a, were first reported.</p><p><b>CONCLUSION</b>PANK2 gene mutations can cause HSS in Chinese patients.</p>