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Background There is scarcity of information on the clinical features and genetics of glucokinase-maturity-onset diabetes of the young (GCK-MODY) in China. The aim of the study was to investigate the clinical and molecular characteristics of Chinese children with GCK-MODY. Methods Eleven children with asymptomatic hyperglycemia and clinically suspected GCK-MODY were identified from the database of children with diabetes in the biggest children’s hospital in South China. Clinical data were obtained from medical records. Blood was collected from the patients and their parents for glucokinase (GCK) gene analysis. Parents without diabetes were tested for fasting glucose and HbA1c. Clinical information and blood for GCK gene analysis were obtained from grandparents with diabetes. GCK gene mutational analysis was performed by polymerase chain reaction and direct sequencing. Patients without a GCK gene mutation were screened by targeted next-generation sequencing (NGS) technology for other MODY genes. Results Nine children tested positive for GCK gene mutations while two were negative. The nine GCK-MODY patients were from unrelated families, aged 1 month to 9 years and 1 month at first detection of hyperglycaemia. Fasting glucose was elevated (6.1–8.5 mmol/L), HbA1c 5.2–6.7% (33.3–49.7 mmol/mol), both remained stable on follow-up over 9 months to 5 years. Five detected mutations had been previously reported: p.Val182Met, c.679 + 1G > A, p.Gly295Ser, p.Arg191Gln and p.Met41Thr. Four mutations were novel: c.483 + 2 T > A, p.Ser151del, p.Met57GlyfsX29 and p.Val374_Ala377del. No mutations were identified in the other two patients, who were also tested by NGS. Conclusions GCK gene mutations are detected in Chinese children and their family members with typical clinical features of GCK-MODY. Four novel mutations are detected.

Measurement of carnitine and acylcarnitines in plasma is important in diagnosis of fatty acid β-oxidation disorders and organic acidemia. The usual method uses flow injection tandem mass spectrometry (FIA-MS/MS), which has limitations. A rapid and more accurate method was developed to be used for high-risk screening and diagnosis. Carnitine and acylcarnitines were separated by hydrophilic interaction liquid chromatography (HILIC) without derivatization and detected with a QTRAP MS/MS System. Total analysis time was 9.0min. The imprecision of within- and between-run were less than 6% and 17%, respectively. Recoveries were in the range of 85-110% at three concentrations. Some acylcarnitine isomers could be separated, such as dicarboxylic and hydroxyl acylcarnitines. The method could also separate interferent to avoid false positive results. 216 normal samples and 116 patient samples were detected with the validated method, and 49 patients were identified with fatty acid oxidation disorders or organic acidemias.

X-linked adrenoleukodystrophy is a common X-linked recessive peroxisomal disorder caused by the mutations in the ABCD1 gene. In this study, we analyzed 19 male patients and 9 female carriers with X-linked adrenoleukodystrophy in South China. By sequencing the ABCD1 gene, 13 different mutations were identified, including 7 novel mutations, and 6 known mutations, and 1 reported polymorphism. Mutation c.1180delG was demonstrated to be de novo mutation. 26.3 % (5/19) patients carried the deletion c.1415_16delAG, which may be the mutational hot spot in South China population. In addition, 73.7 % (14/19) patients were type of childhood cerebral adrenoleukodystrophy, 26.3 %(5/19) were in Addison only. Half of the childhood cerebral adrenoleukodystrophy patients had the adrenocortical insufficiency preceded the onset of neurological symptoms. Furthermore, 5 of 19 cases underwent hematopoietic stem cell transplantation. Our data showed that hematopoietic stem cell transplantation performed at an advanced stage of the cerebral X- linked adrenoleukodystrophy would accelerate the progression of the disease. Good clinical outcome achieved when hematopoietic stem cell transplantation performed at the very early stage of the disease.

Background Childhood cerebral X-linked adrenoleukodystrophy is a rapidly progressive neurodegenerative disorder that affects central nervous system myelin and the adrenal cortex. Hematopoietic stem cell transplantation is the best available curative therapy if performed during the early stages of disease. Only 30% of patients who might benefit from a hematopoietic stem cell transplant will have a full human leukocyte antigen–matched donor, which is considered to be the best choice. Patient Description We present a 5-year-old boy with cerebral X-linked adrenoleukodystrophy whose brain magnetic resonance imaging severity score was 7 and who needed an immediate transplantation without an available full human leukocyte antigen–matched donor. We combined haploidentical and umbilical cord blood sources for transplantation and saw encouraging results. After transplantation, the patient showed neurological stability for 6 months and the level of very long chain fatty acids had decreased. By 1 year, the patient appeared to gradually develop cognition, motor, and visual disturbances resulting from possible mix chimerism. Conclusion Transplantation of haploidentical stem cells combined with the infusion of umbilical cord blood is a novel approach for treating cerebral X-linked adrenoleukodystrophy. It is critical to monitor posttransplant chimerism and carry out antirejection therapy timely for a beneficial clinical outcome.

Medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD) is an autosomal recessive inborn error of mitochondrial fatty acid β-oxidation, caused by mutations in the ACADM gene. As it is the most commonly inherited disorder of the mitochondrial fatty acid oxidation in Caucasians, there are no related reports in China diagnosed by molecular genetic testing. We report here the case of a 2-year-old female patient who had hepatomegaly and abnormal liver function with a common illness, and who had been healthy before. A marked increase found in the concentration of C8-carnitine with the help of tandem mass spectrometry (MS/MS) profile, as well as the presence of hexanoylglycine and cyclohepta acyl glycinate as shown in the urinary gas chromatography/mass spectrometry (GC/MS) were suggestive of MCADD, a diagnosis that was confirmed by genetic analysis that showed compound heterozygosity for a missense mutation, c.362C>T(p.Thr121Ile), and a 4-bp deletion, c.448-453delCTGA, in the medium-chain acyl-coenzyme A dehydrogenase (MCAD) gene, also named ACADM gene. There are no related reports in China. This report broadens the phenotype and genotype of MCADD in China and underlines the difficulty of diagnosis.

BACKGROUND X-linked adrenoleukodystrophy (X-ALD) (OMIM: 300100) is a recessive neurodegenerative disorder caused by defects in the ABCD1 gene on chromosome Xq28. Childhood cerebral ALD (CCALD) is the most frequent phenotype. OBJECTIVE We describe an affected boy who developed normally until he was 8 years old then suffered progressive neurological deficits that ultimately led to death. METHODS Diagnosis was based on clinical symptoms, an abnormal very long chain fatty acid profile in plasma, typical CCALD MRI pattern, and molecular analysis. RESULTS Direct sequencing of the ABCD1 gene in this patient identified a novel splicing mutation (IVS1+1G>A) in intron 1, which is considered to be the pathogenic mutation. CONCLUSION We have identified a novel ABCD1 mutation as the likely cause of CCALD in a Chinese patient.

Short-chain acyl-CoA dehydrogenase deficiency (SCADD) is a rare autosomal recessive inborn error of mitochondrial fatty acid oxidation. It is caused by rare mutations as well as polymorphic susceptibility variants. We describe here the case of a 1-year-old male patient who had growth and mental retardation, seizures, and recurring fever since infancy. Urinary gas chromatography/mass spectrometry (GC/MS) showed elevated levels of ethylmalonic acid. Plasma acylcarnitines on tandem mass spectrometry (MS/MS) and elevations of C4-cartinitine are consistently present. The two polymorphic susceptibility variants of the short-chain acyl-CoA dehydrogenase (SCAD) gene, c.625G>A and c.322G>A, were detected. Because of its highly variable clinical characteristics, there are no related reports in China. This report broadens the phenotype and genotype of SCADD in China and underlines the difficulty of diagnosis.

Glycogen storage disease type Ib (GSDIb) is caused by a deficiency of glucose-6-phosphate translocase (G6PT) activity due to SLC37A4 gene mutations. Most GSDIb patients have recurrent infections and inflammatory bowel disease, with poor prognosis. Detection of SLC37A4 gene mutations is of great significance for the diagnosis, subtyping and outcome prediction of GSD patients. This study aims to analyze SLC37A4 gene mutations in Chinese GSDIb patients and to investigate the relationship between its genotypes and clinical manifestations.All exons and their flanking introns of SLC37A4 gene in 28 Chinese children with a primary diagnosis of GSDIb were screened by PCR combined with direct DNA sequencing to detect SLC37A4 gene mutations.Five SLC37A4 gene mutations were detected in 7 (25%) of the 28 children, i.e., p.Gly149Glu (9/13, 69%), p.Gly115Arg (1/13, 8%), p.Pro191Leu (1/13, 8%), c.959-960 insT (1/13, 8%) and c.870+5GA (1/13, 8%).In this study, c.959-960 insT is a novel mutation and p.Gly149Glu is the most common mutation. p.Gly149Glu may be associated with severe infections in children with GSDIb.

A simple HPLC-MS/MS method has been established to separate and identify underivatized acylcarnitine isomers. Human plasma samples were deproteinized and concentrated. Acylcarnitines were separated on a reverse phase column and detected with triple quadrupole linear ion trap mass spectrometry. Deuterium-labeled internal standards were used for quantitation. To identify acylcarnitines without pure standards, information-dependent acquisition linking to enhanced product ion scan mode was used. 112 acylcarnitines, including stereoisomers, were found in samples of patients. Dicarboxylic acylcarnitines, such as methylmalonylcarnitine and glutarylcarnitine, were detected with high sensitivity. Three stereoisomers of (R,S)2-methyl-3-hydroxy butyrylcarnitine were detected in samples of patients with β-ketothiolase deficiency. Validation results revealed excellent precision and accuracy of the method. In general the within- and between-run coefficients of variation (CV%) were less than 15%, and recoveries were in the range of 92.7-117.5%. In addition, the reference intervals of acylcarnitines for children aged 3-day to13-year old were established. Using the new method and reference intervals, we have correctly diagnosed 49 patients with fatty acid oxidation defects or organic acidemias in 176 high-risk patients.

Background Glycogen Storage Disease Type Ia (GSD Ia) is a group of autosomal recessive inborn errors of metabolism that is caused by deficiency in glucose-6-phosphatase,and it is the major subtype of Liver Glycogen Storage Disease (LGSD) cases. Patients afflicted with GSD Ia cannot maintain glucose homeostasis and manifest hypoglycemia, hepatomegaly, lactic academia. However, we cannot separate GSD Ia form LGSD through clinical manifestations and routine laboratory tests, except for analysis of G6PC gene mutation and assay of glucose-6-phosphatase enzyme activity, which is an invasive method. Therefore, the analysis of G6PC gene mutation is an important method for diagnosing GSD Ia.