OBJECTIVE: To analyze the metabolic profile and genetic variants for newborns with primary carnitine deficiency (PCD) from Guangxi, China. METHODS: From January 2014 to December 2019, 400 575 newborns from the jurisdiction of Guangxi Zhuang Autonomous Region Newborn Screening Center were subjected to tandem mass spectrometry (MS/MS) analysis. Newborns with positive results for PCD and their mothers were recalled for retesting. Those who were still positive were subjected to sequencing of the SLC22A5 gene. RESULTS: Twenty-two newborns and 9 mothers were diagnosed with PCD, which gave a prevalence rate of 1/18 208. Sequencing of 18 newborns and 4 mothers have identified 14 types of SLC22A5 gene variants, with the common ones including c.51C>G (10/44, 22.7%), c.1195C>T (9/44, 20.5%) and c.1400C>G (7/44, 15.9%), The c.517delC(p.L173Cfs*3) and c.1031C>T(p.T344I) were unreported previously and predicted to be pathogenic (PVS1+PM2_supporting+PM3+PP4) and likely pathogenic (PM1+PM2_supporting+PM3+PP3+PP4) based on the American College of Medical Genetics and Genomics standards and guidelines. CONCLUSION c.51C>G, c.1195C>T and c.1400C>G are the most common variants underlying PCD in Guangxi.
Cardiomyopathies ; Carnitine/deficiency* ; China ; Humans ; Hyperammonemia ; Infant, Newborn ; Metabolome ; Muscular Diseases ; Mutation ; Solute Carrier Family 22 Member 5/genetics* ; Tandem Mass Spectrometry

OBJECTIVES: Primary carnitine deficiency (PCD) is a rare fatty acid metabolism disorder that can cause neonatal death. This study aims to analyze carnitine levels and detect SLC22A5 gene in newborns with carnitine deficiency, to provide a basis for early diagnosis of PCD, and to explore the relationship between carnitine in blood and SLC22A5 genotype. METHODS: A total of 40 neonates with low free carnitine (C0<10 μmol/L) in blood were the subjects of the study. SLC22A5 gene was detected by Sanger sequencing to analyze the value of carnitine, the results of gene test and their relationship. RESULTS: A total of 15 variants of SLC22A5 gene were detected, including 11 pathogenic or likely pathogenic variants and 4 variants of uncertain significance. There were 5 new mutations: c.288delG (p.G96fsX33), c.744_745insTCG (p.M258_L259insS), c.752A>G (p.Y251C), c.495 C>A (p.R165E), and c.1298T>C (p.M433T). We found 14 PCD patients including 2 homozygous mutations and 12 heterozygous mutations, 14 with 1 mutation, and 12 with no mutation among 40 children. The C0 concentration of children with SLC22A5 gene homozygous or complex heterozygous mutations was (4.95±1.62) μmol/L in the initial screening, and (3.90±1.33) μmol/L in the second screening. The C0 concentration of children with no mutation was (7.04±2.05) μmol/L in the initial screening, and (8.02±2.87) μmol/L in the second screening. There were significant differences between children with homozygous or compound heterozygous mutations and with no mutation in C0 concentration of the initial and the second screening (both CONCLUSIONS There are 5 new mutations which enriched the mutation spectrum of SLC22A5 gene. C0<5 μmol/L is highly correlated with SLC22A5 gene homozygous or compound heterozygous mutations. Children with truncated mutation may have lower C0 concentration than that with untruncated mutation in the initial screening.
Cardiomyopathies ; Carnitine/deficiency* ; Child ; Humans ; Hyperammonemia/genetics* ; Infant, Newborn ; Muscular Diseases/genetics* ; Mutation ; Solute Carrier Family 22 Member 5/genetics*

BACKGROUND: Late-onset multiple acyl-coA dehydrogenase deficiency (MADD) is an autosomal recessive inherited metabolic disorder. It is still unclear about the muscle magnetic resonance image (MRI) pattern of the distal lower limb pre- and post-treatment in patients with late-onset MADD. This study described the clinical and genetic findings in a cohort of patients with late-onset MADD, and aimed to characterize the MRI pattern of the lower limbs. METHODS: Clinical data were retrospectively collected from clinic centers of Peking University People's Hospital between February 2014 and February 2018. Muscle biopsy, blood acylcarnitines, and urine organic acids profiles, and genetic analysis were conducted to establish the diagnosis of MADD in 25 patients. Muscle MRI of the thigh and leg were performed in all patients before treatment. Eight patients received MRI re-examinations after treatment. RESULTS: All patients presented with muscle weakness or exercise intolerance associated with variants in the electron transfer flavoprotein dehydrogenase gene. Muscle MRI showed a sign of both edema-like change and fat infiltration selectively involving in the soleus (SO) but sparing of the gastrocnemius (GA) in the leg. Similar sign of selective involvement of the biceps femoris longus (BFL) but sparing of the semitendinosus (ST) was observed in the thigh. The sensitivity and specificity of the combination of either "SO+/GA-" sign or "BFL+/ST-" sign for the diagnosis of late-onset MADD were 80.0% and 83.5%, respectively. Logistic regression model supported the findings. The edema-like change in the SO and BFL muscles were quickly recovered at 1 month after treatment, and the clinical symptom was also relieved. CONCLUSIONS This study expands the clinical and genetic spectrums of late-onset MADD. Muscle MRI shows a distinct pattern in the lower limb of patients with late-onset MADD. The dynamic change of edema-like change in the affected muscles might be a potential biomarker of treatment response.
Adolescent ; Adult ; Biopsy ; methods ; Carnitine ; analogs & derivatives ; blood ; Electron-Transferring Flavoproteins ; genetics ; Female ; Hamstring Muscles ; diagnostic imaging ; metabolism ; pathology ; Humans ; Iron-Sulfur Proteins ; genetics ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged ; Multiple Acyl Coenzyme A Dehydrogenase Deficiency ; diagnostic imaging ; genetics ; pathology ; Muscle, Skeletal ; diagnostic imaging ; metabolism ; pathology ; Oxidoreductases Acting on CH-NH Group Donors ; genetics ; Retrospective Studies ; Young Adult

OBJECTIVE: To carry out mutation analysis and prenatal diagnosis for a family affected with primary carnitine deficiency. METHODS: Genomic DNA of the proband was extracted from peripheral blood sample 10 days after birth. The 10 exons and intron/exon boundaries of the SLC22A5 gene were subjected to PCR amplification and Sanger sequencing. The proband's mother was pregnant again two years after his birth. Fetal DNA was extracted from amniocytes and subjected to PCR and Sanger sequencing. RESULTS: Tandem mass spectrometric analysis of the proband revealed low level of plasma-free carnitine whilst organic acids in urine was normal. Compound heterozygous SLC22A5 mutations c.1195C>T (inherited from his father) and c.517delC (inherited from his mother) were detected in the proband. Prenatal diagnosis has detected no mutation in the fetus. The plasma-free carnitine was normal after birth. CONCLUSION Appropriate genetic testing and prenatal diagnosis can prevent further child with carnitine deficiency. The identification of c.517delC, a novel mutation, enriched the spectrum of SLC22A5 mutations.
Cardiomyopathies ; genetics ; Carnitine ; deficiency ; genetics ; Child, Preschool ; DNA Mutational Analysis ; Female ; Humans ; Hyperammonemia ; genetics ; Muscular Diseases ; genetics ; Mutation ; Pregnancy ; Prenatal Diagnosis ; Solute Carrier Family 22 Member 5 ; genetics

OBJECTIVE: To explore the clinical features and variations of ACADVL gene in 9 neonates with very long chain acyl-coenzyme A dehydrogenase deficiency (VLCADD). METHODS: VLCADD was suspected based on the results of neonatal screening by tandem mass spectrometry (MS-MS), with tetradecenoylcarnitine ± tetradecenoylcarnitine/octanoylcarnitine (C14: 1 ± C14: 1/C8) as the mark indexes. Infants with positive outcome were confirmed by sequencing of the ACADVL gene. RESULTS: Among 9 VLCADD cases, one case lost during follow-up, the observed phenotypes comprised 2 with severe early-onset form, 1 with hepatic form and 5 with late-onset form. Optimal outcome was acquired for all patients except the 2 early-onset cases. In total 16 ACADVL variations were detected among the 9 infants, which included 8 novel variations (c.96-105del GCCCGGCCCT, c.541C>T, c.863T>G, c.878+1G>C, c.895A>G, c.1238T>C, c.1276G>A, and c.1505T>A) and 11 missense variations. There were 9 genotypic combinations, including 1 homozygote and 8 compound heterozygotes. Except for two patients carrying null variations, all had a good outcome. CONCLUSION VLCADD is relatively rare in southern China, for which late-onset form is common. Carriers of null variations of the ACADVL gene may have relatively poorer clinical outcome. Above results will provide valuable information for the diagnosis and management of VLCADD.
Acyl-CoA Dehydrogenase, Long-Chain ; deficiency ; genetics ; Carnitine ; China ; Humans ; Infant, Newborn ; Lipid Metabolism, Inborn Errors ; genetics ; Mitochondrial Diseases ; genetics ; Muscular Diseases ; genetics ; Neonatal Screening

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 (P<0.01). Urinary 2-methyl-3-hydroxybutyric acid was 56.04 (7.69-182.20) and methylcrotonyl glycine was 42.83 (9.20-127.01), both were higher than normal levels. In 5 patients urinary 2-methyl-3-hydroxybutyric acid level was remarkably decreased (P<0.05) after treatment. Analysis of ACAT1 gene mutation was performed in six families. Missense variations were detected in 78.6% of the cases. 42.8% of the 7 BKD patients have carried c.1124A>G (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.
Acetyl-CoA C-Acyltransferase ; deficiency ; Amino Acid Metabolism, Inborn Errors ; Carnitine ; Humans ; Infant, Newborn ; Retrospective Studies ; Tandem Mass Spectrometry

OBJECTIVE: To investigate the epidemiological characteristics, phenotype, genotype, and prognosis of medium-chain acyl-CoA dehydrogenase deficiency (MCADD) in the Chinese population. METHODS: A retrospective analysis was performed for the clinical data of the neonates who underwent screening with high-performance liquid chromatography-tandem mass spectrometry from January 2009 to June 2018 and were diagnosed with MCADD by gene detection. RESULTS: A total of 2 674 835 neonates underwent neonatal screening, among whom 12 were diagnosed with MCADD. Gene detection was performed for 10 neonates with MCADD and found 13 mutation types at 16 mutation sites of the ACADM gene, among which there were 7 reported mutations (p.T150Rfs*4, p.M1V, p.R206C, p.R294T, p.G310R, p.M328V, and p.G362E), 5 novel mutations (p.N194D, p.A324P, p.N366S, c.118+3A>G, and c.387+1del G), and 1 exon 11 deletion; p.T150Rfs*4 was the most common mutation (4/16). The detection rate of mutation sites in the ACADM gene was 80%. No phenotype-genotype correlation was observed. Dietary guidance and symptomatic treatment were given after confirmed diagnosis. No acute metabolic imbalance was observed within 4-82 months of follow-up. All neonates had good prognosis except one who had brain dysplasia. CONCLUSIONS MCADD is relatively rare in southern China, and p.T150Rfs*4 is a common mutation in the Chinese population. Cases with positive screening results should be evaluated by octanoylcarnitine C8 value and gene detection.
Acyl-CoA Dehydrogenase ; deficiency ; Carnitine ; China ; Follow-Up Studies ; Humans ; Infant, Newborn ; Lipid Metabolism, Inborn Errors ; Mutation ; Neonatal Screening ; Retrospective Studies

OBJECTIVETo study the gene mutation profile of primary carnitine deficiency (PCD) in neonates, and to provide a theoretical basis for early diagnosis and treatment, genetic counseling, and prenatal diagnosis of PCD.

METHODSAcylcarnitine profile analysis was performed by tandem mass spectrometry using 34 167 dry blood spots on filter paper. The SLC22A5 gene was sequenced and analyzed in neonates with free carnitine (C0) levels lower than 10 μmol/L as well as their parents.

RESULTSIn the acylcarnitine profile analysis, a C0 level lower than 10 μmol/L was found in 10 neonates, but C0 level was not reduced in their mothers. The 10 neonates had 10 types of mutations at 20 different sites in the SLC22A5 gene, which included 4 previously unreported mutations: c.976C>T, c.919delG, c.517delC, and c.338G>A. Bioinformatics analysis showed that the four new mutations were associated with a risk of high pathogenicity.

CONCLUSIONSTandem mass spectrometry combined with SLC22A5 gene sequencing may be useful for the early diagnosis of PCD. Identification of new mutations enriches the SLC22A5 gene mutation profile.

Cardiomyopathies ; diagnosis ; genetics ; Carnitine ; deficiency ; genetics ; Computational Biology ; Genetic Counseling ; Humans ; Hyperammonemia ; diagnosis ; genetics ; Infant, Newborn ; Muscular Diseases ; diagnosis ; genetics ; Mutation ; Solute Carrier Family 22 Member 5 ; genetics ; Tandem Mass Spectrometry

OBJECTIVETo investigate the mutations of SLC22A5 gene in patients with systemic primary carnitine deficiency (CDSP).

METHODSHigh liquid chromatography tandem mass spectrometry (HPLC/MS/MS) was applied to screen congenital genetic metabolic disease and eight patients with CDSP were diagnosed among 77 511 samples. The SLC22A5 gene mutation was detected using massarray technology and sanger sequencing. Using SIFT and PolyPhen-2 to predict the function of protein for novel variations.

RESULTSTotal detection rate of gene mutation is 100% in the eight patients with CDSP. Seven patients had compound heterozygous mutations and one patient had homozygous mutations. Six different mutations were identified, including one nonsense mutation [c.760C>T(p.R254X)] and five missense mutations[c.51C>G(p.F17L), c.250T>A(p.Y84N), c.1195C>T(p.R399W), c.1196G>A(p.R399Q), c.1400C>G(p.S467C)]. The c.250T>A(p.Y84N) was a novel variation, the novel variation was predicted to have affected protein structure and function. The c.760C>T (p.R254X)was the most frequently seen mutation, which was followed by the c.1400C>G(p.S467C).

CONCLUSIONThis study confirmed the diagnosis of eight patients with CDSP on the gene level. Six mutations were found in the SLC22A5 gene, including one novel mutation which expanded the mutational spectrum of the SLC22A5 gene.

Adult ; Amino Acid Sequence ; Base Sequence ; Cardiomyopathies ; diagnosis ; genetics ; metabolism ; Carnitine ; deficiency ; genetics ; metabolism ; DNA Mutational Analysis ; methods ; Female ; Gene Frequency ; Genotype ; Humans ; Hyperammonemia ; diagnosis ; genetics ; metabolism ; Infant, Newborn ; Male ; Muscular Diseases ; diagnosis ; genetics ; metabolism ; Mutation ; Organic Cation Transport Proteins ; genetics ; metabolism ; Reproducibility of Results ; Sensitivity and Specificity ; Sequence Homology, Amino Acid ; Solute Carrier Family 22 Member 5 ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

OBJECTIVETo analyze the clinical and molecular features of a child with carnitine palmitoyltransferase 1A (CPT1A) deficiency.

METHODSClinical data of the child was collected. Blood acylcarnitine was determined with tandem mass spectrometry. DNA was extracted from the child and his parents. All exons and flanking regions of the CPT1A gene were analyzed by PCR and Sanger sequencing.

RESULTSAnalysis showed that the patient carried compound heterozygous mutations c.1787T>C and c.2201T>C of the CPT1A gene, which derived his father and mother, respectively. Both mutations were verified as novel through the retrieval of dbSNP, HGMD and 1000 genome databases. Bioinformatic analysis suggested that the mutations can affect protein function.

CONCLUSIONAcyl carnitine analysis has been the main method for the diagnosis of CPT1A deficiency. The c.1787T>C and c.2201T>C mutations of the CPT1A gene probably underlie the disease in this patient. Gene testing can provide important clues for genetic counseling and prenatal diagnosis.

Base Sequence ; Carnitine O-Palmitoyltransferase ; deficiency ; genetics ; Exons ; Female ; Humans ; Hypoglycemia ; enzymology ; genetics ; Infant ; Lipid Metabolism, Inborn Errors ; enzymology ; genetics ; Male ; Molecular Sequence Data ; Point Mutation ; Pregnancy