OBJECTIVES: To investigate genotype-phenotype characteristics and long-term prognosis of neonatal carbamoyl phosphate synthetase 1 (CPS1) deficiency among children through newborn screening in Zhejiang province. METHODS: The clinical and follow-up data of children with CPS1 deficiency detected through neonatal screening and confirmed by tandem mass spectrometry and genetic testing in Zhejiang Province Newborn Disease Screening Center from September 2013 to August 2023 were retrospectively analyzed. RESULTS: A total of 4 056 755 newborns were screened and 6 cases of CPS1 deficiency were diagnosed through phenotypic and genetic testing. Ten different variations of CPS1 genewere identified in genetic testing, including 2 known pathogenic variations (c.2359C>T and c.1549+1G>T) and 8 unreported variations (c.3405-1G>T, c.2372C>T, c.1436C>T, c.2228T>C, c.2441G>A, c.3031G>A, c.3075T>C and c.390-403del). All patients had decreased citrulline levels (2.72-6.21 μmol/L), and varying degrees of elevated blood ammonia. The patients received restricted natural protein intake (special formula), arginine and supportive therapy after diagnosis, and were followed-up for a period ranging from 9 months to 10 years. Three patients experienced hyperammonemia, and one patient each had attention deficit hyperactivity disorder, transient facial twitching and increased muscle tone. One patient died, while the other five surviving patients had normal scores of the Ages & Stages Questionnaires (ASQ) and Griffiths Development Scales up to the present time; 4 cases had combined height or weight lag and one case was normal in height and weight. CONCLUSIONS Low citrulline levels and hyperammonemia are common in CPS1 deficiency patients in Zhejiang. Most gene variants identified were specific to individual families, and no hotspot mutations were found. Early diagnosis through newborn screening and following standardized treatment can significantly improve the prognosis of the patients.
Child ; Humans ; Infant, Newborn ; Carbamoyl-Phosphate Synthase I Deficiency Disease/therapy* ; Neonatal Screening ; Follow-Up Studies ; Hyperammonemia ; Citrulline/genetics* ; Retrospective Studies ; Mutation

OBJECTIVES: To analyze the results of neonatal screening for congenital hypothyroidism (CH) and hyperphenylalaninemia (HPA) in Zhejiang province from 1999 to 2022. METHODS: A total of 11 922 318 newborns were screened from September 1999 and December 2022 in Zhejiang province. The blood thyroid stimulating hormone (TSH) levels were measured by a fluorescence method and blood phenylalanine (Phe) levels were measured by fluorescence method or tandem mass spectrometry. TSH≥9 μIU/mL was considered positive for CH, while Phe>120 μmol/L and/or Phe/Tyr ratio>2.0 were considered positive for HPA. The positive newborns in screening were recalled, and the gene variations were detected by high-throughput sequencing and MassARRAY tests. RESULTS: The overall neonatal screening rate during 1999-2022 was 89.41% (11 922 318/13 333 929) and the screening rate was increased from 6.46% in 1999 to 100.0% in 2022. A total of 8924 cases of CH were diagnosed among screened newborns with an incidence rate of 1/1336. A total of 563 cases of HPA were diagnosed, including 508 cases of classic phenylketonuria (cPKU) and 55 cases of tetrahydrobiopterin deficiency (BH4D), with an incidence rate of 1/21 176. Ninety-seven out of 8924 cases of CH underwent genetic analysis. Gene mutations were detected in 9 CH related genes, the highest frequency mutations were found in DUOX2 gene (69.0%) with c.3329G>A (p.R1110Q) (18.2%) and c.1588A>T (p.K530X) (17.3%) as the hotspot mutations. There were 81 PAH gene variants detected in a total of 250 cases of cPKU, and c728G>A (p.R243Q) (24.4%), c.721C>T (p.R241C) (15.0%) were the hotspot mutations. Meanwhile 7 novel variants in PAH gene were detected: c.107C>A (p.S36*), c.137G>T (p.G46V), c.148A>G(p.K50E), c.285C>T (p.I95I), c.843-10delTTCC, exon4-7del and c.1066-2A>G. There were 12 PTS gene variants detected in 36 cases of BH4D, and c.259C>T (p.P87S) (31.9%) was the hotspot mutation. CONCLUSIONS The incident of CH has increased from 1999 to 2022 in Zhejiang province, and it is higher than that of national and global levels; while the incidence of HPA is similar to the national average. DUOX2 gene variation is the most common in CH patients; c.728G>A (p.R243Q) is the hotspot mutation in cPKU patients, while c.259C>T (p.P87S) is the hotspot mutation in BH4D patients.
Humans ; Infant, Newborn ; Neonatal Screening ; Dual Oxidases ; Congenital Hypothyroidism/genetics* ; Phenylketonurias/genetics* ; Thyrotropin

OBJECTIVES: To investigate the genotypes and biochemical phenotypes of neonates with abnormal metabolism of butyrylcarnitine (C4). METHODS: One hundred and twenty neonates with increased C4 levels detected by tandem mass spectrometry in the neonatal screening at Children's Hospital, Zhejiang University School of Medicine from January 2018 to June 2023 were included. The initial screening data and recalled data of C4 and C4/C3 were collected and converted into multiples of C4 reference range. Next generation sequencing was performed and the exons with adjacent 50 bp regions of ACAD8 and ACADS genes were captured by liquid phase capture technique. Variant information was obtained by bioinformatic analysis and the pathogenicity were classified according to the American College of Medical Genetics and Genomics criteria. The Wilcoxon rank sum test was used to analyze the differences in C4 levels among neonates with different variation types. RESULTS: In total, 32 variants in ACAD8 gene were detected, of which 7 variants were reported for the first time; while 41 variants of ACADS gene were detected, of which 17 variants have not been previously reported. There were 39 cases with ACAD8 biallelic variations and 3 cases with ACAD8 monoallelic variations; 34 cases with ACADS biallelic variations and 36 cases with ACADS monoallelic variations. Furthermore, 5 cases were detected with both ACAD8 and ACADS gene variations. Inter group comparison showed that the multiples of C4 reference range in initial screening and re-examination of the ACAD8 biallelic variations and ACADS biallelic variations groups were significantly higher than those of the ACADS monoallelic variations group (all P<0.01), while the multiples in the ACAD8 biallelic variations group were significantly higher than those in the ACADS biallelic variations group (all P<0.01). The multiples of C4 reference range in the initial screening greater than 1.5 times were observed in all neonates carrying ACAD8 or ACADS biallelic variations, while only 25% (9/36) in neonates carrying ACADS monoallelic variations. CONCLUSIONS ACAD8 and/or ACADS gene variants are the main genetic causes for elevated C4 in newborns in Zhejiang region with high genotypic heterogeneity. The C4 levels of neonates with biallelic variations are significantly higher than those of neonates with monoallelic variations. The cut-off value for C4 level could be modestly elevated, which could reduce the false positive rate in tandem mass spectrometry neonatal screening.
Child ; Humans ; Infant, Newborn ; Acyl-CoA Dehydrogenase/genetics* ; Genotype ; Phenotype ; Carnitine/metabolism* ; Mutation

Newborn screening (NBS) plays a significant role in reducing the risk of birth defects. NBS in China began in the early 1980s. Under the protection of laws and regulations and the leadership of the national health administration, approved screening centers in public hospitals took the responsibility for publicity, screening, diagnosis, treatment, follow-up and management of birth defects. As of 2022, 31 provinces (autonomous regions and municipalities directly under the central government) have carried out NBS for phenylketonuria, congenital hypothyroidism, and hearing loss, 23 provinces have carried out screening for glucose-6-phosphate dehydrogenase (with a screening rate of 89.24%), and 24 provinces have carried out screening for congenital adrenal cortical hyperplasia (91.45% screening rate). Over the past four decades, screening techniques have evolved from bacterial inhibition, fluorescence analysis, and tandem mass spectrometry for the detection of biochemical markers to genetic testing, which has greatly contributed to the expansion of the types of diseases screened for. The combined use of metabolomics and genomics is currently being explored. Effective management and rigorous quality control of NBS are prerequisites for improving the quality and ensuring the accuracy of screening. The Quality Management System for Newborn Screening System Network (QMS-NBS), established by the National Center for Clinical Laboratories, covers all screening centers and related blood collection agencies. The operation of the QMS-NBS allows the quality and performance of screening to be transparent and measurable, ensuring the quality and efficiency of screening. This article provides an overview of the history of NBS, especially the evolution of policies for the NBS in China, the construction of screening institutions, the number of newborns screened, the incidence rates of screened diseases, the changes in screening technology, the expansion of new diseases screened for, and the quality control of NBS. Overall, the progress in NBS in China has not only benefited from the development and standardization at the technological level, but also benefited from the construction of policies, regulations and ethics.
Infant, Newborn ; Humans ; Neonatal Screening ; Phenylketonurias ; Genetic Testing ; Congenital Hypothyroidism ; China

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.

Objective:To investigate the incidence, clinical characteristics and prognosis of ornithine transcarbamylase deficiency(OCTD) in newborns in Zhejiang Province.Methods:A retrospective research was conducted.A total of 4 261 036 newborns from Department of Genetics and Metabolism, Children′s Hospital, Zhejiang University School of Medicine, between January 2009 and December 2021 were screened for inherited metabolic disorders using tandem mass spectrometry.OCTD was confirmed by urine organic acid and OTC gene analysis.Patients with OTCD received guidance on diet and lifestyle management, and were treated with citrulline and arginine.Long-term follow-up was performed.Their growth and intellectual development were evaluated. Results:A total of 7 patients with OCTD were diagnosed, with an incidence of 1.6/1 million.All patients were males.Two patients had neonatal-onset OCTD, and the other 5 had late-onset OCTD.Symptoms occurred several times in 6 patients, inducing hyperammonemia and hepatic impairment.One patient had no clinical manifestation.One patient died in the neonatal period.Blood citrulline levels were decreased in 7 patients to varying degrees.Uracil levels were increased in 4 patients, and 1 of them was complicated with elevated orotic acid levels.All patients had hemizygote variations in the OTC gene, including 6 missense variations(c.604C>T, c.386G>A, c.779T>C, c.1019C>T, c.594C>G, c.931G>A) and 1 intron variation(c.514-35C>G). Two variants(c.594C>G, c.514-35C>G) were never reported previously. Conclusions:The OTCD incidence by newborn screening is low with 1.6/1 million in Zhejiang province.All patients are males and present hypocitrullinemia.The clinical manifestations of OTCD are highly heterogeneous.The neonatal-onset form is severe and survivors always suffer serious sequelae.The late-onset form is mostly manifested with hyperammonemia and hepatic impairment.There may be association between phenotype and genotype.Two novel OTC variants are identified, which further expands the mutational spectrum.

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.

OBJECTIVE: To investigate the clinical manifestations, biochemical abnormalities and pathogenic variants among children with Short/branched-chain acyl-CoA dehydrogenase (SBCAD) deficiency detected by neonatal screening. METHODS: A total of 2 730 852 newborns were screened from January 2016 to December 2021 with liquid chromatography tandem mass spectrometry. Suspected SBCAD deficiency patients were diagnosed by urine organic acid analysis and high-throughput gene sequencing analysis. The clinical, biochemical and genetic changes of the confirmed cases were analyzed, in addition with guidance for diet and life management, L-carnitine supplement, and survey of growth and intellectual development. RESULTS: Twelve cases of SBCAD deficiency were diagnosed, which yielded a prevalence of 1/227 571. The lsovaleryl carnitine (C5) of primary screening blood samples was between 0.6 and 2.1 µmol/L, all exceeded the normal range. C5/acety1 carnitine (C2) was between 0.02 and 0.12, with 6 cases exceeding the normal range. C5/propionyl carnitine (C3) was between 0.1 and 1.16, with 5 cases exceeding the normal range. Free carnitine (C0) was between 18.89 and 58.12 µmol, with 1 case exceeding the normal range. Three neonates with abnormal screening results were recommended to have appropriate restriction for protein intake and two were given L-carnitine. During follow-up, their C5 has ranged from 0.22 to 2.32 µmol/L, C5/C2 has ranged from 0.01 to 0.31, C5/C3 has ranged from 0.14 to 1.7. C5 or C5/C2 and C5/C3 were transiently normal in all patients except for case 8 during the neonatal screening and follow-up. C0 was 17.42 ∼ 76.83 µmol/L Urine organic acid analysis was carried out in 9 of the 12 cases, and 2-methylbutyroglycine was elevated in 8 cases. Urine organic acid analysis was carried out in 9 cases, and 2-methylbutyrylglycine was increased in 8 cases. Genetic analysis was carried out for 11 children, and in total 6 ACADSB gene variants were identified, which included 4 missense variants (c.655G>A, c.923G>A, c.461G>A, c.1165A>G), 1 frameshift variant (c.746del) and 1 nonsense variant (c.275C>G). Among these, the C.461G>A variant was unreported previously. The most common variants were c.1165A>G (40.9%) and C.275C>G (22.7%). The patients were followed up for 18 days to 55 months. Only one patient had mental retardation, with the remainders having normal physical and mental development. CONCLUSION SBCAD deficiency is a rare disease. The detection rate of newborn screening in this study was 1/227 571. Early intervention can be attained in most asymptomatic patients through neonatal screening. In this study, the common gene variants are c.1165A>G and c.275C>G.
Humans ; Infant, Newborn ; Amino Acid Metabolism, Inborn Errors/genetics* ; Carnitine ; Neonatal Screening/methods*

OBJECTIVE: To assess the value of genetic screening by high-throughput sequencing (HTS) for the early diagnosis of neonatal diseases. METHODS: A total of 2 060 neonates born at Ningbo Women and Children's Hospital from March to September 2021 were selected as the study subjects. All neonates had undergone conventional tandem mass spectrometry metabolite analysis and fluorescent immunoassay analysis. HTS was carried out to detect the definite pathogenic variant sites with high-frequency of 135 disease-related genes. Candidate variants were verified by Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA). RESULTS: Among the 2 060 newborns, 31 were diagnosed with genetic diseases, 557 were found to be carriers, and 1 472 were negative. Among the 31 neonates, 5 had G6PD, 19 had hereditary non-syndromic deafness due to variants of GJB2, GJB3 and MT-RNR1 genes, 2 had PAH gene variants, 1 had GAA gene variants, 1 had SMN1 gene variants, 2 had MTTL1 gene variants, and 1 had GH1 gene variants. Clinically, 1 child had Spinal muscular atrophy (SMA), 1 had Glycogen storage disease II, 2 had congenital deafness, and 5 had G6PD deficiency. One mother was diagnosed with SMA. No patient was detected by conventional tandem mass spectrometry. Conventional fluorescence immunoassay had revealed 5 cases of G6PD deficiency (all positive by genetic screening) and 2 cases of hypothyroidism (identified as carriers). The most common variants identified in this region have involved DUOX2 (3.93%), ATP7B (2.48%), SLC26A4 (2.38%), GJB2 (2.33%), PAH (2.09%) and SLC22A5 genes (2.09%). CONCLUSION Neonatal genetic screening has a wide range of detection and high detection rate, which can significantly improve the efficacy of newborn screening when combined with conventional screening and facilitate secondary prevention for the affected children, diagnosis of family members and genetic counseling for the carriers.
Child ; Infant, Newborn ; Humans ; Female ; Prospective Studies ; Connexins/genetics* ; Connexin 26/genetics* ; Glucosephosphate Dehydrogenase Deficiency ; Mutation ; Sulfate Transporters/genetics* ; DNA Mutational Analysis ; Genetic Testing/methods* ; Deafness/genetics* ; Neonatal Screening/methods* ; Hearing Loss, Sensorineural/genetics* ; High-Throughput Nucleotide Sequencing ; Solute Carrier Family 22 Member 5/genetics*

Objective:To investigate the accuracy, effectiveness and feasibility of MassARRAY genotyping assay in the diagnoses of neonatal genetic metabolic diseases.Methods:This is a retrospective study. From December 2016 to January 2020, newborns were screened by tandem mass spectrometry at the Zhejiang Newborn Screening Center, among which the data of 7 922 suspected positive cases of genetic metabolic diseases were collected. These patients were then tested for the common variants of 27 genetic metabolic diseases by MassARRAY genotyping assay, along with further testing using Sanger or next-generation sequencing used to verify and/or further search for potential variants.Results:A total of 1 408 cases were tested with MassARRAY. Among these, 307 cases were confirmed with certain genetic metabolic diseases. The detection rate of hyperphenylalaninemia was the highest, followed by primary carnitine deficiency, short acyl-coA dehydrogenase deficiency and methylmalonic acidemia. With these cases, the consistency of Sanger sequencing and MassARRAY was 100% (307/307). Another 287 cases were identified as carriers by MassARRAY with a 49.1% (141/287) consistency in reference to Sanger sequencing, mainly involving SLC22A5 and MCCC1 genes. Meanwhile, 50.8% (146/287) of these cases were found to have another variant mainly involving PAH, PTS and ACADS genes. The remaining 814 cases have no variants; 158 cases out of these patients have continuously abnormal amino acids, acyl carnitines, urine organic acid and/or other biochemical indices, and were tested by next-generation sequencing, among which 38% (60/158) were detected with two variants. In this study, a total of 513 patients with genetic metabolic disease were diagnosed, and the detection rate of MassARRAY was 59.8% (307/513). Conclusions:MassARRAY genotyping assay can be used as an early molecular screening method for neonatal genetic metabolic diseases. The detection rate is particularly high in diseases with a high concentration of hotspot variants, such as hyperphenylalaninemia and primary carnitine deficiency. The future application value of MassARRAY should be further improved by continuously optimizing its ability to identify new disease genes and potential variable sites.