Hypophosphatemia rickets is a rare disease that is divided into two categories,namely,hereditary and ac-quirability.Its clinical manifestations include growth disorders,limb deformities and dysfunction,poor mineralization of the teeth,and growth retardation in children as well as hyperparathyroidism,osteoarthritis,osteomalacia,and pseudofrac-ture in adults.Oral manifestations include non-carious teeth with recurrent apical periodontitis,periapical abscess and even cellulitis,periodontitis,and early tooth loss.X-linked hypophosphatemia rickets(XLHR)accounts for approximate-ly 80％of all hypophosphatemia rickets.We report a 3-year-old child with XLHR whose first diagnosis was apical peri-odontitis of multiple non-carious and non-traumatic teeth.Through medical history,clinical examination,laboratory ex-amination,radiographic findings,genotype testing,and literature analysis,we analyze the pathogenesis,clinical manifes-tations,radiographic features,diagnosis and differential diagnosis,treatment,and follow-up.This work provides refer-ence for clinical diagnosis and treatment and reduces missed diagnosis and misdiagnosis by dentists.

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

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 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 analyze the oral phenotype and gene variation of children with hypophosphatasia (HPP), and explore the genotype-phenotype correlations.Methods:Eight children diagnosed with HPP from January 2008 to January 2023 in The Children′s Hospital, Zhejiang University School of Medicine were recruited in this study. The pathogenic genes of 5 of them were sequentially analyzed and all of their oral manifestations, laboratory tests and genetic variation types were retrospectively analyzed.Results:A total of 8 children were recruited in the study, 3 males and 5 females, aged from 20 to 104 months, whose main complaints were premature deciduous tooth loss. Among them, 3 children were diagnosed with odonto HPP, and the other 5 children were diagnosed with childhood HPP, including 2 children was odonto HPP at the first diagnosis and modified as childhood HPP at the age of 5. The age range of first deciduous tooth loss is 9 to 18 months, and the age range of diagnosis was 20 to 104 months. The patients of odonto HPP only showed premature loss of deciduous anterior tooth, while the patients with childhood HPP also showed premature loss of multiple deciduous molars. Panoramic radiographic film revealed enlarged pulp chambers and radicular canals in some primary and permanent teeth. The enamel hypoplasia, hypoplastic short roots, and alveolar resorption of deciduous molar were observed in some cases. The serum alkaline phosphatase (ALP) (30-107 U/L) levels of all the patients were lower than that in the normal children of same age and gender, and the ALP value of the 1-3 years old girls with childhood HPP (30-33 U/L) was lower than that of the three children with odonto HPP (61-107 U/L), but there was no significant difference in statistical analysis. There were 8 variation sites of ALP liver/bone/kidney (ALPL) gene detected in 5 children and their families, all of which were missense variation, including the new variants in the mutations of c.1334C>G (p.Ser445Cys) and c.1259G>T (p.Gly420Val) that were not reported in the literature. One case was autosomal dominant inheritance and other 4 cases were complex heterozygous variation with autosomal recessive inheritance.Conclusions:Pediatric stomatologists are often the first doctors to detect childhood and odonto HPP. Diagnosis of mild HPP is often delayed. The severity of HPP is related to serum ALP level and ALPL gene mutation sites.

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.

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.

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.
Child ; Cyclohexanones ; therapeutic use ; Genotype ; Humans ; Infant ; Infant, Newborn ; Neonatal Screening ; Nitrobenzoates ; therapeutic use ; Tandem Mass Spectrometry ; Tyrosinemias ; diagnosis ; drug therapy ; genetics

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), while there was no significant difference between MCCC1-paternal-mutation group and wild-type group (>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.
Carbon-Carbon Ligases ; genetics ; Carnitine ; analogs & derivatives ; metabolism ; Female ; Genetic Testing ; Genetic Variation ; Humans ; Infant, Newborn ; Male ; Mutation ; Neonatal Screening ; Urea Cycle Disorders, Inborn ; genetics

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.