Biochemical and genetic characteristics of 40 neonates with carnitine deficiency / 中南大学学报(医学版)

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 (C0G (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.

Clinical and genetic characteristics of primary carnitine deficiency identified by neonatal screening / 中华医学遗传学杂志

Objective@#To study the prevalence, clinical and genetic characteristics of primary carnitine deficiency (PCD).@*Methods@#From January 2013 to December 2017, 720 667 newborns and their mothers were tested for PCD by tandem mass spectrometry. Potential mutations of carnitine transporter gene SLC22A5 among suspected PCD patients were analyzed. Dietary guidance and L-carnitine supplementation were provided to the parents. Growth and intelligence development were surveyed during follow-up.@*Results@#In total 21 neonates and 6 mothers were diagnosed with PCD, which yielded an incidence of 1 in 34 317. Eighteen SLC22A5 mutations were detected, which included 4 novel mutations, namely c. 1484T>C, c. 394-1G>T, c. 431T>C and c. 265-266insGGCTCGCCACC. Eighteen patients were found to carry compound heterozygous mutations and 3 have carried homozygous SLC22A5 mutations. Three mothers carried compound heterozygous mutations and 2 carried homozygous mutations. Common mutations included c. 1400C>G (42.3%), c. 760C>T (11.5%) and c. 51C>G (7.7%). During the 8 ~ 42 month follow-up, neonates with PCD showed no clinical symptoms but normal growth. Blood level of free carnitine was raised in all mothers after the treatment.@*Conclusion@#The incidence of neonatal PCD in Henan is 1 in 34 317, with the most common mutation being c. 1400C>G. Above finding has enriched the spectrum of SLC22A5 gene mutations.

Screening,diagnosis and treatment of primary carnitine deficiency / 中国实用儿科杂志

Primary carnitine deficiency is an autosomal recessive hereditary disease caused by the mutation of SLC22 A5 gene,which leads to increased carnitine excretion in urine and low level of carnitine in blood,tissues and cells. Due to the heterogeneity and non-specificity of the clinical manifestations of PCD,it is easy to be misdiagnosed or missed and it is potentially fatal without timely treatment. This disease can be detected early through the newborn screening. Maternal carnitine deficiency and the secondary carnitine deficiency caused by other diseases should be excluded. Genetic test can give a clear diagnosis. Avoiding hunger and use of oral L-carnitine supplementation to maintain normal plasma carnitine concentrations are effective treatments.

Newborn screening for fatty acid oxidation disorders / 中国实用儿科杂志

()of recessive hereditary diseases caused by the dysfunction of enzymes required for fatty acids to enter mitochondria or fatty acid beta-oxidation,including carnitine transport disorders and fatty acid beta-oxidation disorders. Clinical symptoms are non-specific,involving multiple organs,such as liver,myocardium,skeletal muscle,brain and kidney. Most FAOD patients diagnosed by newborn screening have no clinical symptoms or mild symptoms through early intervention management,but they are prone to acute onset or even sudden death under stress conditions such as hunger and exercise. Long-term follow-up and management can effectively reduce the mortality and morbidity rate of FAOD.

Screening and SLC22A5 gene mutations of the patients with primary carnitine deficiency / 中华实用儿科临床杂志

Objective To investigate the clinical features and SLC22A5 gene mutation types in patients with primary carnitine deficiency(PCD).Methods The free carnitine(CO) and acylcarnitine levels in the blood of 210 908 neonates from newborn screening program and 576 children with suspected clinical inherited metabolic diseases were measured by using liquid chromatography tandem mass spectrometry method during September 2015 to December 2017,after that the SLC22A5 gene mutations were analyzed in the children with low CO level and the diagnosis was made.The clinical characteristics,laboratory findings,genotypes,treatment and prognosis were retrospectively analyzed in patients.Paired sample t test was used to compare the biochemical indexes of patients before and after the treatments.Results Ten children were diagnosed with PCD(9 cases from newborn screening program,1 case from clinical patients),and 7 children were diagnosed with maternal carnitine deficiency.After treatment with oral Levocarnitine,the free carnitine and acylcarnitine of the patients returned to the normal levels.The clinical symptoms disappeared in 1 patient out of clinical patients,and the other 16 patients from newborn screening program were asymptomatic and showed normal growth and development.Seventeen patients got genetic analysis,and 10 types of mutations were found,including c.1400C ＞ G,c.1462C ＞ T,c.797C ＞ T,c.95A ＞ G,c.92C ＞ T,c.1093A ＞ C,c.761G ＞ A,c.865C ＞ T,c.428C ＞ T,c.1195C ＞ T,among which two of them (c.1093A ＞ C and c.92C ＞ T) were novel mutations.The most common mutation of SLC22A5 gene was c.1400C ＞ G.Conclusions Liquid chromatography tandem mass spectrometry technology is sufficient to screen newborns and maternal carnitine deficiency,and the c.1400C ＞ G mutation is found at the highest frequency in Xuzhou area.If patients receive early treatment,they may have a good prognosis.

Clinical and gene analysis of primary carnitine deficiency found by neonatal screening / 临床儿科杂志

Objective To explore the clinical feature and gene types in patients with primary carnitine deficiency. MethodsClinical data of 6 patients with primary carnitine deficiency and 2 patients with maternal carnitine deficiency found in the screening by tandem mass spectrometry technology during December 2013 to December 2016 were retrospectively analyzed. Results The free carnitine levels of 8 patients in initial and recall screening were 5.85±1.65 μmol/L and 5.22±1.02 μmol/L. Two pathogenic alleles were detected in each patient with primary carnitine deficiency by genetic and metabolic disease panel based on Ion Torrent semiconductor sequencing. After treatment with oral L-carnitine, the free carnitine levels of 6 patients with primary carnitine deficiency were 20.24±3.88 μmol/L. The carnitine levels returned to normal after mixed feeding for one week in 2 patients with maternal carnitine deficiency, and no genetic diagnosis was carried out. Conclusion Primary carnitine deficiency can be effectively detected using tandem mass spectrometry technology and next generation sequencing panel and the prognosis is good with early standard treatment.

The SLC22A5 genetic analysis in Chinese patients with systemic primary carnitine deficiency / 中华内分泌代谢杂志

Objective To investigate the clinical and biochemical metabolic features of 12 patients with systemic primary carnitine deficiency(CDSP) and to identify the SLC22A5 gene mutation types of the disease. Method The clinical and biochemical data were collected by retrospective analysis. DNA direct sequencing and multiplex ligation dependent probe amplification(MLPA)were applied for SLC22A5 gene analysis. Result Among 12 patients with CDSP, 3 cases had evident infection factors, 6 cases with convulsions, 5 cases manifested liver hypertrophy, 8 cases with hyperammonemia, and 9 cases showed myocardial damage. All CDSP patients were detected biallelic pathogenic mutation in SLC22A5 gene by direct sequencing. The gene types include IVS2+1G>T, c.3G>T(p.Met1Ile), c.760C>T(p.Arg254X), c.1400C>G(p.Ser467Cys), c.844dupc(p.Arg282fs), c.338G>A(p.Cys113Tyr), c.51C>G(p.Phe17Leu), c.659A>T(p.Glu220Val), and c.1365dupC(p.Thr456fs). c.659A>T(p.Glu220Val) and c.1365dupC(p.Thr456fs)are novel mutations. One female patient was maternal CDSP, her child had abnormal newborn screening. The allele frequency of c.760C>T(p.Arg254X) and c.1400C>G(p.Ser467Cys) were 37.5%(9/24)and 29.2%(7/24)respectively. The MLPA test results of all patients were negative. Conclusion The clinical manifestations are complex and various in patients with CDSP. Point and small InDel(insertions/deletions)mutation constitute the major alteration in SLC22A5 gene. c.1400C>G(p.Ser467Cys) might be another prevalence mutation type in Chinese CDSP patient.

Fever,poor response, convulsions, and hepatomegaly / 中华实用儿科临床杂志

Objective To investigate the differential diagnosis of Reye syndrome and the characteristics of primary carnitine deficiency,and to provide diagnostic strategy for similar cases.Methods There was a case presented with fever,poor response,convulsions and hepatomegaly hospitalized in Wuhan Children's Hospital,and the clinical manifestations were described,the physical examination was comprehensively conducted,the auxiliary examination results were recorded,some pediatric specialists from ICU,neurology department,genetic metabolic department,digestive system department were invited to discuss the case.The treatment was adjusted according to the suggested opinions;the treatment effects and the final diagnosis were tracked.Results The primary diagnosis of the case was central nervous system infection or toxic encephalopathy at the time of admission,but Reye syndrome could not be excluded.Although the cerebrospinal fluid test and brain MRI examination detected nothing abnormal,liver function suggested alanine aminotrans ferase ALT increase,blood sugar decrease,the liver volume increase,which was detected by liver ultrasound.Blood amino acids examination revealed the carnitine level decreased,and it was confirmed as primary carnitine deficiency in the end.L-carnitine was used to treat the disease,and its effect was good.Conclusions Great importance should be attached to children with onset age,physical check-up,and multidisciplinary cooperation.Use monism to explain the illness and the auxiliary inspection as far as possible,so that it can get early diagnosis and treatment,and the outcome is good.

Screening and short-term follow-up of newborns and mothers with primary carnitine deficiency / 中华内分泌代谢杂志

ObjectiveTo explore the screening and therapeutic efficacy of primary carnitine deficiency (PCD) in newborns and mothers.Methods164245 newborns and suspected mothers were investigated for PCD by tandem mass spectrometry (MS/MS).The overall epidemiology,prognosis,and follow-up of the screening program were investigated.ResultsTotally 55 suspected cases were identified at the primary screening stage.Four newborns and three mothers were confirmed as cases of PCD.The incidence rate of newborns was 1 ∶ 40076.All the patients showed normal growth and development during the follow-up.Blood free carnitine level was raised in all three mothers after treatment.ConclusionsScreening for PCD with MS/MS in newborns may represent a valuable procedure in preventive medicine by enabling early diagnosis and treatment before the onset of symptoms.This protocol is also highly efficient and applicable in diagnosis of mothers with PCD.

Implementación de un método mediante el uso de sustratos tritiados comoherramienta diagnóstica de la deficiencia de OCTN2 / Implementation of a method using tritiated substrates as a diagnostic tool for OCTN2 deficiency

Introducción: El transporte de carnitina dentro de la célula es mediado por el transportador mitocondrial de los ácidos grasos de cadena larga. La deficiencia primaria de carnitina se debe a una deficiencia del transportador OCTN2. Objetivos: El presente estudio tuvo como objetivo el análisis de las tasas de oxidación de sustratos tritiados por fibroblastos de pacientes que presentaban deficiencia primaria de carnitina y controles. Materiales y métodos: Fibroblastos de pacientes y controles se incubaron con [3H]-palmitato y [3H]-miristato y se determinó la oxidación de los mismos en nmol/h/mg proteína. Resultados: Encontrßndose deficiente la oxidación de sustratos tritiados en mßs de 60% por parte de los fibroblastos procedentes de los pacientes que presentaban la deficiencia de OCTN2. Conclusión: Esta técnica modificada permite el diagnóstico in vitro de la deficiencia primaria de carnitina.

Introduction: The transport of carnitine into the cell is mediated by a high-affinity sodium-dependent plasmalemmal carnitine transporter, OCTN2. Carnitine is a zwitterion essential for the mitochondrial oxidation of long-chain fatty acids. Primary carnitine deficiency is a consequence of the deficiency of OCTN2. Objective: The objective of the present study was to analyse the oxidation rate of tritiated substrates by fibroblasts from patients suffering OCTN2 deficiency and controls. Materials and methods: Fibroblasts from patients and controls were incubated with [3H]-palmitate and [3H]-miristate and the oxidation of these substrates were measured in nmol/hour/mg protein. Results: We found depressed the oxidation of tritiated substrates in fibroblasts from patients suffering the deficiency of OCTN2 in more than 60%.Conclusion: This modified technique enables us the in vitro diagnosis or primary carnitine deficiency.

Diagnóstico in vitro de la deficiencia primaria de carnitina / In vitro diagnosis of primary carnitine deficiency

El transportador de carnitina (OCTN2) es fundamental para el metabolismo mitocondrial de los ácidos grasos de cadena larga. Su carencia produce la deficiencia primaria de carnitina. El presente estudio tuvo como objetivo el análisis de los ácidos grasos producidos por fibroblastos incubados en presencia de sustratos deuterados, mediante cromatografía de gases acoplada a espectrometría de masas (GC - MS) como herramienta diagnóstica de la deficiencia primaria de carnitina. Se encontró un perfil característico en esta deficiencia, lo que permite su diagnóstico in vitro.

Carnitine transporter (OCTN2) is required for the mitochondrial metabolism of long-chain fatty acids. Primary carnitine deficiency is a consequence of its deficiency. The objective of the present study was to analyse the fatty acids produced by fibroblasts incubated with deuterated substrates, using gas chromatography-mass spectrometry as a diagnostic tool for the diagnosis of VLCAD deficiency. A characteristic profile for this deficiency was found using this technique which enables its in vitro diagnosis.

Clinical and pathological features of lipid storage myopathy caused by primary carnitine deficiency / 临床神经病学杂志

Objective To analyze the clinical and pathological features of lipid storage myopathy (LSM) caused by primary carnitine deficiency (CD).Methods The clinical data of 4 cases of possible LSM caused by primary CD were analyzed retorspectively.Results The clinical features of the 4 patients were subacute or chronic onset, proximal muscle weakness and exercise intolerance. Elevated levels of creatases were measured in serum and myogenic damage was found by EMG examination. Frozen sections of muscle biopsy samples showed many fibers contained numerous vacuoles which was stained by oil red O. No ragged red fiber (RRF) was seen in MGT stain. Type I fibers were more severely affected. In electron microscopy, the prominent abnormality was the presence of excessive amounts of fatty droplets in muscle fibers and subsarcolemmal regions with mild increased mitochondria.Treatment with glucocorticoid and energy supplement had been clinically beneficial. Conclusions Fatigue and muscle weakness are prominent manifestations in LSM caused by primary CD. The main changes are accumulation of lipid droplets in muscle specimen without prominent abnormality in structure in mitochondria. Good clinic effect may be caused by therapy with glucocorticoid.