Autism spectrum disorder (ASD) is a group of the neurodevelopment disorders presenting as an isolated ASD or more complex forms, where a broader clinical phenotype comprised of developmental delay ...and intellectual disability is present. Both the isolated and complex forms have a significant causal genetic component and submicroscopic genomic copy number variations (CNV) are the most common identifiable genetic factor in these patients. The data on microarray testing in ASD cohorts are still accumulating and novel loci are often identified; therefore, we aimed to evaluate the diagnostic efficacy of the method and the relevance of implementing it into routine genetic testing in ASD patients. A genome-wide CNV analysis using the Agilent microarrays was performed in a group of 150 individuals with an isolated or complex ASD. Altogether, 11 (7.3%) pathogenic CNVs and 15 (10.0%) variants of unknown significance (VOUS) were identified, with the highest proportion of pathogenic CNVs in the subgroup of the complex ASD patients (14.3%). An interesting case of previously unreported partial
UPF3B
gene deletion was identified among the pathogenic CNVs. Among the CNVs with unknown significance, four VOUS involved genes with possible correlation to ASD, namely genes
SNTG2
,
PARK2
,
CADPS2
and
NLGN4X
. The diagnostic efficacy of aCGH in our cohort was comparable with those of the previously reported and identified an important proportion of genetic ASD cases. Despite the continuum of published studies on the CNV testing in ASD cohorts, a considerable number of VOUS CNVs is still being identified, namely 10.0% in our study.
Autism spectrum disorder (ASD) is a complex developmental disorder in which communication and behavior are affected. A number of studies have investigated potential biomarkers, including uremic ...toxins. The aim of our study was to determine uremic toxins in the urine of children with ASD (143) and compare the results with healthy children (48). Uremic toxins were determined with a validated high-performance liquid chromatography coupled to mass spectrometry (LC-MS/MS) method. We observed higher levels of p-cresyl sulphate (pCS) and indoxyl sulphate (IS) in the ASD group compared to the controls. Moreover, the toxin levels of trimethylamine N-oxide (TMAO), symmetric dimethylarginine (SDMA), and asymmetric dimethylarginine (ADMA) were lower in ASD patients. Similarly, for pCS and IS in children classified, according to the intensity of their symptoms, into mild, moderate, and severe, elevated levels of these compounds were observed. For mild severity of the disorder, elevated levels of TMAO and comparable levels of SDMA and ADMA for ASD children as compared to the controls were observed in the urine. For moderate severity of ASD, significantly elevated levels of TMAO but reduced levels of SDMA and ADMA were observed in the urine of ASD children as compared to the controls. When the results obtained for severe ASD severity were considered, reduced levels of TMAO and comparable levels of SDMA and ADMA were observed in ASD children.
: Autism spectrum disorder (ASD) is a developmental disorder characterized by deficits in social interaction, restricted interest and repetitive behavior. Oxidative stress in response to ...environmental exposure plays a role in virtually every human disease and represents a significant avenue of research into the etiology of ASD. The aim of this study was to explore the diagnostic utility of four urinary biomarkers of oxidative stress.
One hundred and thirty-nine (139) children and adolescents with ASD (89% male, average age = 10.0 years, age range = 2.1 to 18.1 years) and 47 healthy children and adolescents (49% male, average age 9.2, age range = 2.5 to 20.8 years) were recruited for this study. Their urinary 8-OH-dG, 8-isoprostane, dityrosine and hexanoil-lisine were determined by using the ELISA method. Urinary creatinine was determined with the kinetic Jaffee reaction and was used to normalize all biochemical measurements. Non-parametric tests and support vector machines (SVM) with three different kernel functions (linear, radial, polynomial) were used to explore and optimize the multivariate prediction of an ASD diagnosis based on the collected biochemical measurements. The SVM models were first trained using data from a random subset of children and adolescents from the ASD group (
= 70, 90% male, average age = 9.7 years, age range = 2.1 to 17.8 years) and the control group (
= 24, 45.8% male, average age = 9.4 years, age range = 2.5 to 20.8 years) using bootstrapping, with additional synthetic minority over-sampling (SMOTE), which was utilized because of unbalanced data. The computed SVM models were then validated using the remaining data from children and adolescents from the ASD (
= 69, 88% male, average age = 10.2 years, age range = 4.3 to 18.1 years) and the control group (
= 23, 52.2% male, average age = 8.9 years, age range = 2.6 to 16.7 years).
: Using a non-parametric test, we found a trend showing that the urinary 8-OH-dG concentration was lower in children with ASD compared to the control group (unadjusted
= 0.085). When all four biochemical measurements were combined using SVMs with a radial kernel function, we could predict an ASD diagnosis with a balanced accuracy of 73.4%, thereby accounting for an estimated 20.8% of variance (
< 0.001). The predictive accuracy expressed as the area under the curve (AUC) was solid (95% CI = 0.691-0.908). Using the validation data, we achieved significantly lower rates of classification accuracy as expressed by the balanced accuracy (60.1%), the AUC (95% CI = 0.502-0.781) and the percentage of explained variance (
= 3.8%). Although the radial SVMs showed less predictive power using the validation data, they do, together with ratings of standardized SVM variable importance, provide some indication that urinary levels of 8-OH-dG and 8-isoprostane are predictive of an ASD diagnosis.
: Our results indicate that the examined urinary biomarkers in combination may differentiate children with ASD from healthy peers to a significant extent. However, the etiological importance of these findings is difficult to assesses, due to the high-dimensional nature of SVMs and a radial kernel function. Nonetheless, our results show that machine learning methods may provide significant insight into ASD and other disorders that could be related to oxidative stress.
osteopenia is common in children, adolescents, and young adults with severe cerebral palsy (cp; spastic quadriplegia) living in residential care, and frequently results in atraumatic fractures. on ...clinical grounds 67 patients (34 males, 33 females) with severe cp (gross motor function classification system gmfcs levels iv or v) aged 5 to 25 years (median 20y) were divided into three groups with increasing likelihood of severe impairment of bone quality: (1) patients without fractures and without anticonvulsant medication (n=13); (2) patients without fractures and with anticonvulsant medication (n=45); (3) patients with fractures and with anticonvulsant medication (n=9). evaluation included measurements of quantitative ultrasound (qus) of the calcaneus, multiple serum analyses, and determination of urinary bone-resorption markers. values of the quantitative ultrasound index (qui) were significantly different (p=0.001): group 1 (median 56.9; interquartile range 43.8–75.3); group 2 (49.9; 40.0–60.0); group 3 (35.6; 30.5–38.5). when comparing values of laboratory serum and urine in the three groups, we found significant differences in values of serum bone alkaline phosphatase (p=0.001), serum parathyroid hormone (pth; p=0.002), serum albumin (p=0.020), and urinary deoxypyridinoline/creatinine ratio (p=0.004). in multiple regression analysis, no laboratory variable was found to be an independent predictor of qui. qus of the calcaneus may be a useful method to assess bone quality and fracture risk in children and young adults with severe cp living in residential care, independent of information from laboratory data.
Mutations in the gene encoding thymidine kinase 2 (TK2) result in the myopathic form of mitochondrial DNA depletion syndrome which is a mitochondrial encephalomyopathy presenting in children. In ...order to unveil some of the mechanisms involved in this pathology and to identify potential biomarkers and therapeutic targets we have investigated the gene expression profile of human skeletal muscle deficient for TK2 using cDNA microarrays.
We have analysed the whole transcriptome of skeletal muscle from patients with TK2 mutations and compared it to normal muscle and to muscle from patients with other mitochondrial myopathies. We have identified a set of over 700 genes which are differentially expressed in TK2 deficient muscle. Bioinformatics analysis reveals important changes in muscle metabolism, in particular, in glucose and glycogen utilisation, and activation of the starvation response which affects aminoacid and lipid metabolism. We have identified those transcriptional regulators which are likely to be responsible for the observed changes in gene expression.
Our data point towards the tumor suppressor p53 as the regulator at the centre of a network of genes which are responsible for a coordinated response to TK2 mutations which involves inflammation, activation of muscle cell death by apoptosis and induction of growth and differentiation factor 15 (GDF-15) in muscle and serum. We propose that GDF-15 may represent a potential novel biomarker for mitochondrial dysfunction although further studies are required.
Atraumatic fractures are often seen in children and adolescents with cerebral palsy (CP) and epilepsy in full-time care. Increased bone fragility was postulated to be due to osteopenia resulting from ...a combination of factors including immobilization and antiepileptic treatment. The aim of this study was to determine the effect of vitamin D and calcium substitution on bone mineral density (BMD) in a group of children with CP in full-time care. Twenty children with the most severe form of CP (spastic quadriplegia) who had been treated with antiepileptic drugs for a relatively long period of time were included in the study. Physical examination and laboratory analyses excluded other possible causes of osteopenia. BMD was measured by dual X-ray absorptiometry. Thirteen patients were treated for 9 months with 1,25-dihydroxy-cholecalciferol vitamin D (0.25 mcg daily) and with calcium (500 mg daily). Seven control children were used for observation only. BMD greatly increased in the treated group, while children with CP in full-time care who did not receive vitamin D and calcium substitution continued to lose their bone mass. It can be concluded that the addition of vitamin D and calcium increases BMD in children with the most severe form of CP, who are receiving antiepileptic drugs.
Osteopenia is common in children, adolescents, and young adults with severe cerebral palsy (CP; spastic quadriplegia) living in residential care, and frequently results in atraumatic fractures. On ...clinical grounds 67 patients (34 males, 33 females) with severe CP (Gross Motor Function Classification System GMFCS levels IV or V) aged 5 to 25 years (median 20y) were divided into three groups with increasing likelihood of severe impairment of bone quality: (1) patients without fractures and without anticonvulsant medication (n=13); (2) patients without fractures and with anticonvulsant medication (n=45); (3) patients with fractures and with anticonvulsant medication (n=9). Evaluation included measurements of quantitative ultrasound (QUS) of the calcaneus, multiple serum analyses, and determination of urinary bone‐resorption markers. Values of the quantitative ultrasound index (QUI) were significantly different (p=0.001): group 1 (median 56.9; interquartile range 43.8–75.3); group 2 (49.9; 40.0–60.0); group 3 (35.6; 30.5–38.5). When comparing values of laboratory serum and urine in the three groups, we found significant differences in values of serum bone alkaline phosphatase (p=0.001), serum parathyroid hormone (PTH; p=0.002), serum albumin (p=0.020), and urinary deoxypyridinoline/creatinine ratio (p=0.004). In multiple regression analysis, no laboratory variable was found to be an independent predictor of QUI. QUS of the calcaneus may be a useful method to assess bone quality and fracture risk in children and young adults with severe CP living in residential care, independent of information from laboratory data.
BACKGROUND: Mutations in the gene encoding thymidine kinase 2 (TK2) result in the myopathic form of mitochondrial DNA depletion syndrome which is a mitochondrial encephalomyopathy presenting in ...children. In order to unveil some of the mechanisms involved in this pathology and to identify potential biomarkers and therapeutic targets we have investigated the gene expression profile of human skeletal muscle deficient for TK2 using cDNA microarrays. RESULTS: We have analysed the whole transcriptome of skeletal muscle from patients with TK2 mutations and compared it to normal muscle and to muscle from patients with other mitochondrial myopathies. We have identified a set of over 700 genes which are differentially expressed in TK2 deficient muscle. Bioinformatics analysis reveals important changes in muscle metabolism, in particular, in glucose and glycogen utilisation, and activation of the starvation response which affects aminoacid and lipid metabolism. We have identified those transcriptional regulators which are likely to be responsible for the observed changes in gene expression. CONCLUSION: Our data point towards the tumor suppressor p53 as the regulator at the centre of a network of genes which are responsible for a coordinated response to TK2 mutations which involves inflammation, activation of muscle cell death by apoptosis and induction of growth and differentiation factor 15 (GDF-15) in muscle and serum. We propose that GDF-15 may represent a potential novel biomarker for mitochondrial dysfunction although further studies are required.
BACKGROUND: Mutations in the gene encoding thymidine kinase 2 (TK2) result in the myopathic form of mitochondrial DNA depletion syndrome which is a mitochondrial encephalomyopathy presenting in ...children. In order to unveil some of the mechanisms involved in this pathology and to identify potential biomarkers and therapeutic targets we have investigated the gene expression profile of human skeletal muscle deficient for TK2 using cDNA microarrays. RESULTS: We have analysed the whole transcriptome of skeletal muscle from patients with TK2 mutations and compared it to normal muscle and to muscle from patients with other mitochondrial myopathies. We have identified a set of over 700 genes which are differentially expressed in TK2 deficient muscle. Bioinformatics analysis reveals important changes in muscle metabolism, in particular, in glucose and glycogen utilisation, and activation of the starvation response which affects aminoacid and lipid metabolism. We have identified those transcriptional regulators which are likely to be responsible for the observed changes in gene expression. CONCLUSION: Our data point towards the tumor suppressor p53 as the regulator at the centre of a network of genes which are responsible for a coordinated response to TK2 mutations which involves inflammation, activation of muscle cell death by apoptosis and induction of growth and differentiation factor 15 (GDF-15) in muscle and serum. We propose that GDF-15 may represent a potential novel biomarker for mitochondrial dysfunction although further studies are required.
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