Carnitine is necessary for transport of long-chain fatty acids into mitochondria, to enter the beta-oxidation cycle. Four carnitine cycle defects have been described. The carnitine transporter mediates carnitine transport across the plasma membrane. Symptoms include hypoketotic hypoglycaemia and cardiomyopathy. Some affected subjects are asymptomatic. Newborn screening detects very low levels of free carnitine in some but not all. Carnitine palmitoyltransferase type IA (CPTI) transports long-chain fatty acyl-CoAs across the outer mitochondrial membrane. Affected infants have hypoketotic hypoglycaemia with catabolic stress, but otherwise remain well. Newborn screening tests reveal elevated free carnitine, (elevated C0/C16+C18). Sensitivity is unclear and confirmation needs leukocyte or fibroblast assays. Carnitine-acylcarnitine translocase transfers fatty acylcarnitines across the inner mitochondrial membrane. The most common presentation is sudden death in the first days. Carnitine palmitoyltransferase type II (CPTII) converts long-chain acylcarnitines to long-chain acylCoAs for beta-oxidation. Severe deficiency is lethal. Newborn screening for both disorders reveals elevated palmitoylcarnitine and enzymology or mutation analysis is needed for diagnosis. Late-onset CPTII is the most common disorder, presenting as muscle pain and rhabdomyolysis on severe exercise. All 4 disorders can be detected by newborn screening, with variable sensitivity. Late-onset CPTII probably cannot be detected. Carnitine transporter, CPTI and late-onset CPTII have proven treatment strategies.
Carnitine ; metabolism ; Carnitine O-Palmitoyltransferase ; deficiency ; Humans ; Infant, Newborn ; Metabolism, Inborn Errors ; diagnosis ; enzymology ; Neonatal Screening

Carnitine O-Palmitoyltransferase ; deficiency ; Female ; Humans ; Infant, Newborn

Cardiomyopathies ; diagnosis ; therapy ; Carnitine ; deficiency ; Female ; Humans ; Hyperammonemia ; diagnosis ; therapy ; Infant ; Muscular Diseases ; diagnosis ; therapy

This study aimed to identify the type of carnitine palmitoyltransferase 2 (CPT2) gene mutation in the child with carnitine palmitoyltransferase II (CPT II) deficiency and her parents and to provide the genetic counseling and prenatal diagnosis for the family members. As the proband, a 3-month-old female baby was admitted to the hospital due to fever which had lasted for 8 hours. Tandem mass spectrometric analysis for blood showed an elevated plasma level of acylcarnitine, which suggested CPT II deficiency. The genomic DNA was extracted from peripheral blood of the patient and her parents. Five exon coding regions and some intron regions at the exon/intron boundaries of the CPT2 gene were analyzed by PCR and Sanger sequencing. Amniotic fluid was taken from the mother during the second trimester, and DNA was extracted to analyze the type of CPT2 gene mutation. Sanger sequencing results showed that two mutations were identified in the CPT2 gene of the proband: c.886C>T (p.R296X) and c.1148T>A (p.F383Y), which were inherited from the parents; the second child of the mother inherited the mutation of c.886C>T (p.R296X) and showed normal acylcarnitine spectrum and normal development after birth. It is concluded that the analysis of CPT2 gene mutations in the family suggested that the proband died of CPT II deficiency and that the identification of the mutations was helpful in prenatal diagnosis in the second pregnancy.
Carnitine O-Palmitoyltransferase ; deficiency ; genetics ; Female ; Humans ; Infant ; Metabolism, Inborn Errors ; diagnosis ; genetics ; Mutation ; Prenatal Diagnosis

Cardiomyopathies ; diagnosis ; Carnitine ; deficiency ; Humans ; Hyperammonemia ; diagnosis ; Infant, Newborn ; Male ; Muscular Diseases ; diagnosis

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

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*

OBJECTIVETo analyze the clinical characteristics and genetype of one children who had been diagnosed with pyruvate dehydrogenase complex deficiency.

METHODComprehensive analyses of this case were performed, including clinical symptoms, signs, biochemical examinations and therapeutic effects. The eleven exons and splicing areas of PDHA1 were amplified with genomic DNA from whole blood. And variations were investigated by sequencing the PCR product. The patient was diagnosed with pyruvate dehydrogenase complex deficiency by sequence analysis of PDHA1 gene.

RESULTThe patient was a 2 years and 4 monthes old boy. He presented with muscle hypotonia and weakness for one year, and experienced recurrent episodes of unstable head control, unable to sit by himself or stand without support, with persistently hyperlactacidemia. Metabolic testing revealed blood lactate 5.37 mmol/L, pyruvate 0.44 mmol/L, and lactate/pyruvate ratio was 12.23. MRI of the brain showed hyperintense signals on the T2 and T2 Flair weighted images in the basal ganglia bilaterally. Sequence analysis of PDHA1 gene showed a G>A point mutation at nucleotide 778, resulting in a substitution of glutarnine for arginine at position 263 (R263Q). And the diagnosis of pyruvate dehydrogenase complex deficiency was identified. By giving the therapy with ketogenic diet, vitamin B(1), coenzyme Q(10) and L-carnitine , the boy was in a stable condition.

CONCLUSIONThe severity and the clinical phenotypes of pyruvate dehydrogenase complex deficiency varied. Sequence analysis of PDHA1 gene revealed a 788G>A (R263Q) mutation. Patients who presented with unexplained muscle hypotonia, weakness and hyperlactacidemia could be diveded by gene analysis. And appropriate treatment can improve the quality of life.

Brain ; Carnitine ; Child, Preschool ; Exons ; genetics ; Humans ; Magnetic Resonance Imaging ; Male ; Mutation ; Phenotype ; Pyruvate Dehydrogenase (Lipoamide) ; genetics ; Pyruvate Dehydrogenase Complex Deficiency Disease ; diagnosis ; genetics ; Pyruvic Acid

Asian Continental Ancestry Group ; genetics ; Carnitine Acyltransferases ; deficiency ; genetics ; China ; Founder Effect ; Humans ; Infant, Newborn ; Male ; Mutation ; Sudden Infant Death ; genetics

Medium- and short-chain acyl-CoA dehydrogenase deficiency is a disorder of fatty acid β-oxidation. Gene mutation prevents medium- and short-chain fatty acids from entry into mitochondria for oxidation, which leads to multiple organ dysfunction. In this study, serum acylcarnitines and the organic acid profile in urea were analyzed in two children whose clinical symptoms were hypoglycemia and metabolic acidosis. Moreover, gene mutations in the two children and their parents were evaluated. One of the patients was a 3-day-old male who was admitted to the hospital due to neonatal asphyxia, sucking weakness, and sleepiness. The serum acylcarnitine profile showed increases in medium-chain acylcarnitines (C6-C10), particularly in C8, which showed a concentration of 3.52 μmol/L (reference value: 0.02-0.2 μmol/L). The analysis of organic acids in urea gave a normal result. Sanger sequencing revealed a reported c.580A>G (p.Asn194Asp) homozygous mutation at exon 7 of the ACADM gene. The other patient was a 3-month-old female who was admitted to the hospital due to cough and recurrent fever for around 10 days. The serum acylcarnitine profile showed an increase in serum C4 level, which was 1.66 μmol/L (reference value: 0.06-0.6 μmol/L). The analysis of organic acids in urea showed an increase in the level of ethyl malonic acid, which was 55.9 (reference value: 0-6.2). Sanger sequencing revealed a reported c.625G>A (p.Gly209Ser) homozygous mutation in the ACADS gene. This study indicates that screening tests for genetic metabolic diseases are recommended for children who have unexplained metabolic acidosis and hypoglycemia. Genetic analyses of the ACADM and ACADS genes are helpful for the diagnosis of medium- and short-chain acyl-CoA dehydrogenase deficiency.
Acyl-CoA Dehydrogenase ; deficiency ; genetics ; Carnitine ; analogs & derivatives ; blood ; Female ; Humans ; Infant ; Infant, Newborn ; Lipid Metabolism, Inborn Errors ; genetics ; Male ; Mutation ; Urea ; analysis