To investigate the clinical and laboratory features of very long chain acyl-CoA dehydrogenase deficiency ( VLCADD ) and the correlations between its genotype and phenotype.Eleven patients diagnosed as VLCADD of Shanghai Jiaotong University School of Medicine seen from September 2006 to May 2014 were included. There were 9 boys and 2 girls, whose age was 2 d-17 years. Analysis was performed on clinical features, routine laboratory examination, and tandem mass spectrometry (MS-MS) , gas chromatography mass spectrometry (GC-MS) and genetic analysis were conducted.All cases had elevated levels of blood tetradecanoylcarnitine (C14:1) recognized as the characteristic biomarker for VLCADD. The eleven patients were classified into three groups: six cases in neonatal onset group, three in infancy onset group form patients and two in late onset group. Neonatal onset patients were characterized by hypoactivity, hypoglycemia shortly after birth. Infancy onset patients presented hepatomegaly and hypoglycemia in infancy. The two adolescent patients showed initial manifestations of exercise intolerance or rhabdomyolysis. Six of the eleven patients died at the age of 2-8 months, including four neonatal onset and two infant onset patients, with one or two null mutations. The other two neonatal onset patients were diagnosed since early birth through neonatal screening and their clinical manifestation are almost normal after treatments. Among 11 patients, seventeen different mutations in the ACADVL gene were identified, with a total mutation detection rate of 95.45% (21/22 alleles), including eleven reported mutations ( p. S22X, p. G43D, p. R511Q, p. W427X, p. A213T, p. C215R, p. G222R, p. R450H, p. R456H, c. 296-297delCA, c. 1605 + 1G > T) and six novel mutations (p. S72F, p. Q100X, p. M437T, p. D466Y, c. 1315delG insAC, IVS7 + 4 A > G). The p. R450H was the most frequent mutation identified in three alleles (13.63%, 3/22 alleles), followed by p. S22X and p. D466Y mutations which were detected in two alleles (9.09%, 2/22 alleles).The ACADVL gene mutations were heterozygous in our patients. The mortality of neonatal onset form and infant onset form is much higher than the late onset form patients, suggesting a certain correlation between the genotype and phenotype was found. The earlier diagnosis and treatment of VLCADD are of vital importance for the improvement of the prognosis of the patients.
OBJECTIVE With the emergence of enzyme replacement therapy and progress in bone marrow transplantation, treatment of mucopolysaccharidosis (MPS) is much more promising than ever. In order to benefit from these therapies, determination of the defective enzyme is the prerequisite for any individual patient. To make definite diagnosis for patients suspected of having MPS clinically, the authors established six lysosomal enzymatic assays for leucocytes, including alpha-L-iduronidase, iduronate-2-sulfatase, N-acetylgalactosamine 6-sulfatase, beta-galactosidase, arylsulfatase B, beta-glucuronidase, which are the corresponding enzymes of type I, type II, type IVA, type IVB, type VI, and type VII, respectively. METHOD Seventy patients suspected of having MPS were enrolled from outpatient clinics of the Department of Pediatric Endocrinologic, Genetic and Metabolic Diseases in Xinhua Hospital. Their ages spanned from 10 months to 25 years with the average age 5.7 years. Of them 49 were male and 21 were female. Leukocytes were isolated with Dextran from peripheral blood of suspected patients. Activity of leukocyte alpha-L-iduronidase, iduronate-2-sulfatase, N-acetylgalactosamine 6-sulfatase, beta-galactosidase, beta-glucuronidase were measured using their specific artificial fluorescent substrates, while arylsulfatase B were determined by colorimetric assay with dipotassium 2-hydroxy-5-nitrophenyl sulfate as the substrate. RESULT Of the 70 clinically suspected cases totally 47 were confirmed of having mucopolysaccharidosis, of whom 7 cases were type I, 28 cases type II, 12 cases type IVA. These data show that type II is the predominant form of MPS in China, succeeded by MPS type IVA. It was also noted that type II has the most variable clinical manifestations and 8 out of 12 type IVA patients had the unique lax joints. CONCLUSION The present study suggest that type II might be the predominant form of MPS cases in China, followed by type IVA and type I.
To analyze the levels of methylmalonic acid and methylcitrate in urine, propionylcarnitine (C3) in plasma and C3/acetylcarnitine (C2) of patients with methylmalonic acidemia (MMA) and explore their applications in the diagnosis of MMA.From December 2003 to March 2012, a total of 162 patients with MMA (MMA group) and 200 healthy children (control group) of Xinhua Hospital, Shanghai Jiaotong University School of Medicine were recruited. MMA patients with a definite classification were divided into 2 groups: isolate MMA group (n = 51) and MMA complicated with homocysteinemia group (n = 65). Gas chromatography-mass spectrometry was used to measure the urine levels of methylmalonic acid and methylcitrate and tandem mass spectrometry to measure the blood levels of free carnitine (C0), acylcarnitines and methionine (Met).In the MMA group, the median levels of methylmalonic acid (259.10 (6.73 - 6429.28)), methylcitrate (4.39 (0 - 248.96)), C3 (8.52 (1.50 - 52.11) µmol/L) and C3/C2 (0.73(0.28 - 2.89)) were all higher than the upper limit values (0.2 - 3.6, 0 - 1.1, 0.50 - 4.00 µmol/L and 0.04 - 0.25 respectively). And they were all higher than those in the control group (0 (0 - 1.87), 0.10 (0 - 1.84), 1.40 (0.53 - 3.90) µmol/L, 0.10 (0.04 - 0.23), all P < 0.01). C3/C2 increased significantly in 15 patients while the C3 level remained normal. The median level of Met was normal in the isolate MMA group. But in patients with homocysteinemia, the level of 8.71 (0.68 - 31.95) µmol/L was below the reference value (10.00 - 35.00 µmol/L) and lower than that in the isolate MMA group (15.35 (4.18 - 59.50) µmol/L) and the control group (15.59 (10.20 - 34.68) µmol/L, all P < 0.05).Significant increases in the urine level of methylmalonic acid and C3/C2 may be specific to MMA. Organic acid analyses of gas chromatography-mass spectrometry and acylcarnitines with tandem mass spectrometry are required for a definite diagnosis of this disorder. And repeated tests and genomic mutation analysis are necessary for patients with mildly abnormal biochemical indices.
Isovaleric acidemia (IVA) is an autosomal recessive inborn error of leucine metabolism caused by a deficiency of the mitochondrial enzyme isovaleryl-CoA dehydrogenase (IVD) resulting in the accumulation of derivatives of isovaleryl-CoA. IVA is considered to be a severe, potentially life-threatening disorder that manifests with acute neonatal encephalopathy in approximately half of affected individuals, and recurrent episodes of vomiting, lethargy, coma and varying degrees of developmental delay in the other half of patients. This study was conducted to investigate the clinical features and IVD gene mutations of a Chinese patient with IVA.The clinical features, routine laboratory data, blood amino acid and acylcarnitine profiles and urinary organic acid profiles of a patient with IVA were reviewed. Whole coding exons of IVD gene were PCR-amplified for DNA sequencing. The novel mutation c.466G > C (G127A) was confirmed by RFLP with restriction endonuclease Hph I.The patient was a 2 year and 7 month-old boy. At 3 days of age, he began to show severe vomiting and acidosis. He was treated with pyloromyotomy at 10 days of age. His recurrent vomiting was not ameliorated until beginning transition to a diet that included more carbohydrate from 4 months. He had 3 recurrent severe vomiting and acidosis later and showed obvious psychomotor retardation. Blood spot acylcarnitine profiles by MS-MS demonstrated an elevation of C5-carnitine with a peak concentration of 12.89 micromol/L (< 0.5 micromol/L). Organic acid analysis of urine by GC-MS revealed a relatively high level of isovaleric glycine. Mutational analysis of the patient's IVD gene revealed heteroallelic mutations of c.149G > A (R21H) and c.466G > C (G127A) which is a novel missense mutation. G127A mutation was not detected in any of 50 normal controls.From the clinical course, obvious elevation of blood C5-carnitine and urine isovaleric glycine, this patient's disorder should be classified as "metabolically severe" type of IVA which suggest that c.466G > C (G127A) mutation could severely damage the function of the IVD protein. To our knowledge, this is the first characterization of IVD gene mutations in the mainland of China.
To study the incidence of various enzyme deficiency in tetrahydrobiopterin (BH4) metabolism and the related gene mutation among the patients with motor disturbance and mental retardation.One hundred patients with unknown motor disturbance and mental retardation were referred to this study. All patients were performed by phenylalanine (Phe) and BH4 loading test, urinary pterin analysis and dihydropteridine reductase (DHPR) activity. Some patients received the dopa treatment for diagnosis of dopa-responsive dystonia (DRD). The analysis of GTP cyclohydrolase 1 gene (GCH1) mutation for DRD patients and the analysis of 6-pyruvoyl tetrahydropterin synthase (PTS) gene mutations for PTS deficient patients were done under the consent from their parents.Seventy of 100 patients had normal basic blood Phe levels, six (6%) patients were diagnosed as DRD. Thirty patients had hyperphenylalaninemia (HPA), eight (8%) were diagnosed as PTS deficiency and 22(22%) were diagnosed as phenylalanine hydroxylase (PAH) deficiency. All patients had normal DHPR activity. The mutation IVS5+3insT of GCH1 was found in 2 patients with DRD. Seven kinds of PTS mutations were found in 8 patients with PTS deficiency, and 75% of the mutations were 259C-->T,286G-->A and 155A-->G.Some patients with unknown motor disturbance and mental retardation may suffer from BH4 metabolism related diseases. Theses patients are necessary to be screened for such kind of diseases in order to confirm the diagnosis.
Congenital lipoid adrenal hyperplasia (CLAH) is an autosomal recessive inherited disorder, characterized by deficiency of adrenal and gonadal steroid hormones. Recent studies have shown that mutations in the gene for steroidogenic acute regulatory protein (StAR) cause this most severe genetic disorder in steroid hormone biosynthesis. StAR is a mitochondrial protein promotes cholesterol transfer from outer mitochondrial membrane to the inner mitochondrial membrane, where the cholesterol serves as a substrate for P450scc and initiates steroidogenesis. So far, more than 30 different mutations in the StAR gene have been found in the patients with CLAH from various ethnic groups. None of CLAH patients in the Chinese population has been previously reported. In the present study we analyzed the StAR gene in a Chinese patient with CLAH.The patient who was a 19-yr-old phenotypic female, has a 46, XY karyotype. Endocrinological evaluation was performed. Genomic DNA samples were abstracted from the bloods of the patient and his parents. Polymerase chain reaction (PCR), direct DNA sequencing, family analysis and restriction enzyme digestion analysis were used to detect and confirm the mutations of StAR gene.Endocrine evaluation of the patient showed extremely elevated basal concentrations of serum ACTH and gonadotropin and minimal concentration of gonadal steroids. An ACTH stimulation test indicated basal serum dehydroepiandrosterone and 17-hydroxyprogesterone were lower than normal detectable range and had no obvious increase after the ACTH stimulation. Automatic sequencing of 7 exons of the StAR gene with the polymerase chain reaction products of the genomic DNA revealed compound heterozygous for a novel nonsense mutation Q77X in exon 3 and the frameshift mutation 838delA in exon 6. The father carried Q77X mutation and the mother carried 838delA mutation. The restriction enzyme site of the Q77X mutation was examined by endonucleotidase BfaI. Furthermore, this mutation was not found in a series of 20 alleles of normal individuals.Q77X is the novel mutation found in the patient with CLAH. Q77X and 838delA compound mutations could inactivate the StAR function and give rise to clinically manifest CLAH. This case is the first Chinese patient with CLAH identified by molecular genetic analysis. DNA-based analysis of StAR gene will be helpful for the diagnosis of CLAH.
To develop and evaluate a simple, fast and accurate prenatal diagnosis method for glycogen storage disease Ia (GSD Ia) in Chinese.This study involved 3 unrelated families. Genomic DNA samples were extracted from the blood of three GSD Ia patients and their parents, from the amniocytes of 3 fetuses and the blood of 2 newborns. By the way of restriction enzyme analysis, the screening for 727G-->T and R83H mutations of glucose-6-phosphatase gene was carried out in conjunction with 1176 nucleotide polymorphism linkage analysis so as to make the gene and prenatal diagnosis of 3 GSD Ia families. Direct DNA sequencing of the corresponding PCR products was used to confirm the unveiled mutations and 1176 nucleotide polymorphism.Three probands were homozygotes for the 727G-->T mutation and their parents were heterozygotes for this mutation. The fetuses of family 1 and 3 were heterozygotes for the 727G-->T mutation, whereas the fetus of family 2 did not carry this mutation. The 1176 nucleotide polymorphisms of 3 fetuses were different from those of the corresponding probands. The prenatal diagnoses of family 1 and 2 were confirmed by the postnatal biochemical and molecular studies.These findings suggest that the screening for 727G-->T and R83H mutations in conjunction with the 1176 polymorphism linkage analysis be a simple, fast and accurate method for gene and prenatal diagnosis of GSD Ia in Chinese.
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