Can Ficicioglu

Structural Variation of Chromosomes in Autism Spectrum Disorder

Structural variation (copy number variation [CNV] including deletion and duplication, translocation, inversion) of chromosomes has been identified in some individuals with autism spectrum disorder (ASD), but the full etiologic role is unknown. We performed genome-wide assessment for structural abnormalities in 427 unrelated ASD cases via single-nucleotide polymorphism microarrays and karyotyping. With microarrays, we discovered 277 unbalanced CNVs in 44% of ASD families not present in 500 controls (and re-examined in another 1152 controls). Karyotyping detected additional balanced changes. Although most variants were inherited, we found a total of 27 cases with de novo alterations, and in three (11%) of these individuals, two or more new variants were observed. De novo CNVs were found in approximately 7% and approximately 2% of idiopathic families having one child, or two or more ASD siblings, respectively. We also detected 13 loci with recurrent/overlapping CNV in unrelated cases, and at these sites, deletions and duplications affecting the same gene(s) in different individuals and sometimes in asymptomatic carriers were also found. Notwithstanding complexities, our results further implicate the SHANK3-NLGN4-NRXN1 postsynaptic density genes and also identify novel loci at DPP6-DPP10-PCDH9 (synapse complex), ANKRD11, DPYD, PTCHD1, 15q24, among others, for a role in ASD susceptibility. Our most compelling result discovered CNV at 16p11.2 (p = 0.002) (with characteristics of a genomic disorder) at approximately 1% frequency. Some of the ASD regions were also common to mental retardation loci. Structural variants were found in sufficiently high frequency influencing ASD to suggest that cytogenetic and microarray analyses be considered in routine clinical workup.

Multiple phenotypes in phosphoglucomutase 1 deficiency

BACKGROUND Congenital disorders of glycosylation are genetic syndromes that result in impaired glycoprotein production. We evaluated patients who had a novel recessive disorder of glycosylation, with a range of clinical manifestations that included hepatopathy, bifid uvula, malignant hyperthermia, hypogonadotropic hypogonadism, growth retardation, hypoglycemia, myopathy, dilated cardiomyopathy, and cardiac arrest. METHODS Homozygosity mapping followed by whole-exome sequencing was used to identify a mutation in the gene for phosphoglucomutase 1 (PGM1) in two siblings. Sequencing identified additional mutations in 15 other families. Phosphoglucomutase 1 enzyme activity was assayed on cell extracts. Analyses of glycosylation efficiency and quantitative studies of sugar metabolites were performed. Galactose supplementation in fibroblast cultures and dietary supplementation in the patients were studied to determine the effect on glycosylation. RESULTS Phosphoglucomutase 1 enzyme activity was markedly diminished in all patients. Mass spectrometry of transferrin showed a loss of complete N-glycans and the presence of truncated glycans lacking galactose. Fibroblasts supplemented with galactose showed restoration of protein glycosylation and no evidence of glycogen accumulation. Dietary supplementation with galactose in six patients resulted in changes suggestive of clinical improvement. A new screening test showed good discrimination between patients and controls. CONCLUSIONS Phosphoglucomutase 1 deficiency, previously identified as a glycogenosis, is also a congenital disorder of glycosylation. Supplementation with galactose leads to biochemical improvement in indexes of glycosylation in cells and patients, and supplementation with complex carbohydrates stabilizes blood glucose. A new screening test has been developed but has not yet been validated. (Funded by the Netherlands Organization for Scientific Research and others.).

Clinical and molecular features of mitochondrial DNA depletion due to mutations in deoxyguanosine kinase.

Published mutations in deoxyguanosine kinase (DGUOK) cause mitochondrial DNA depletion and a clinical phenotype that consists of neonatal liver failure, nystagmus and hypotonia. In this series, we have identified 15 different mutations in the DGUOK gene from 9 kindreds. Among them, 12 have not previously been reported. Nonsense, splice site, or frame‐shift mutations that produce truncated proteins predominate over missense mutations. All patients who harbor null mutations had early onset liver failure and significant neurological disease. These patients have all died before 2‐years of age. Conversely, two patients carrying missense mutations had isolated liver disease and are alive in their 4th year of life without liver transplant. Five subjects were detected by newborn screening, with elevated tyrosine or phenylalanine. Consequently, this disease should be considered if elevated tyrosine is identified by newborn screening. Mitochondrial DNA content was below 10% of controls in liver in all but one case and modestly reduced in blood cells. With this paper a total of 39 different mutations in DGUOK have been identified. The most frequent mutation, c.763_c.766dupGATT, occurs in 8 unrelated kindreds. 70% of mutations occur in only one kindred, suggesting full sequencing of this gene is required for diagnosis. The presentation of one case with apparent viral hepatitis, without neurological disease, suggests that this disease should be considered in patients with infantile liver failure regardless of the presence of neurological features or apparent infectious etiology.

A Delphi clinical practice protocol for the management of very long chain acyl-CoA dehydrogenase deficiency

INTRODUCTION Very long chain acyl-CoA dehydrogenase (VLCAD) deficiency is a disorder of oxidation of long chain fat, and can present as cardiomyopathy or fasting intolerance in the first months to years of life, or as myopathy in later childhood to adulthood. Expanded newborn screening has identified a relatively high incidence of this disorder (1:31,500), but there is a dearth of evidence-based outcomes data to guide the development of clinical practice protocols. This consensus protocol is intended to assist clinicians in the diagnosis and management of screen-positive newborns for VLCAD deficiency until evidence-based guidelines are available. METHOD The Oxford Centre for Evidence-based Medicine system was used to grade the literature review and create recommendations graded from A (evidence level of randomized clinical trials) to D (expert opinion). Delphi was used as the consensus tool. A panel of 14 experts (including clinicians, diagnostic laboratory directors and researchers) completed three rounds of survey questions and had a face-to-face meeting. RESULT Panelists reviewed the initial evaluation of the screen-positive infant, diagnostic testing and management of diagnosed patients. Grade C and D consensus recommendations were made in each of these three areas. The panel did not reach consensus on all issues, particularly in the dietary management of asymptomatic infants diagnosed by newborn screening.

A Phase 3 Trial of Sebelipase Alfa in Lysosomal Acid Lipase Deficiency

BACKGROUND Lysosomal acid lipase is an essential lipid-metabolizing enzyme that breaks down endocytosed lipid particles and regulates lipid metabolism. We conducted a phase 3 trial of enzyme-replacement therapy in children and adults with lysosomal acid lipase deficiency, an underappreciated cause of cirrhosis and severe dyslipidemia. METHODS In this multicenter, randomized, double-blind, placebo-controlled study involving 66 patients, we evaluated the safety and effectiveness of enzyme-replacement therapy with sebelipase alfa (administered intravenously at a dose of 1 mg per kilogram of body weight every other week); the placebo-controlled phase of the study was 20 weeks long and was followed by open-label treatment for all patients. The primary end point was normalization of the alanine aminotransferase level. Secondary end points included additional disease-related efficacy assessments, safety, and side-effect profile. RESULTS Substantial disease burden at baseline included a very high level of low-density lipoprotein cholesterol (≥190 mg per deciliter) in 38 of 66 patients (58%) and cirrhosis in 10 of 32 patients (31%) who underwent biopsy. A total of 65 of the 66 patients who underwent randomization completed the double-blind portion of the trial and continued with open-label treatment. At 20 weeks, the alanine aminotransferase level was normal in 11 of 36 patients (31%) in the sebelipase alfa group and in 2 of 30 (7%) in the placebo group (P=0.03), with mean changes from baseline of -58 U per liter versus -7 U per liter (P<0.001). With respect to prespecified key secondary efficacy end points, we observed improvements in lipid levels and reduction in hepatic fat content (P<0.001 for all comparisons, except P=0.04 for triglycerides). The number of patients with adverse events was similar in the two groups; most events were mild and were considered by the investigator to be unrelated to treatment. CONCLUSIONS Sebelipase alfa therapy resulted in a reduction in multiple disease-related hepatic and lipid abnormalities in children and adults with lysosomal acid lipase deficiency. (Funded by Synageva BioPharma and others; ARISE ClinicalTrials.gov number, NCT01757184.).

Duarte (DG) galactosemia: A pilot study of biochemical and neurodevelopmental assessment in children detected by newborn screening

UNLABELLED Newborn screening for galactosemia has shown a high prevalence of partial galactose uridyl transferase deficiencies such as Duarte (DG) galactosemia. STUDY OBJECTIVE To determine whether (a) there is any clinical impact of DG galactosemia on development (b) there is a relationship between outcome and biochemical parameters in patients who receive no treatment. STUDY POPULATION Twenty-eight children with DG galactosemia. Group-I-17 children had a lactose restricted diet in the first year of life. Group-II-11 children had a regular diet since birth. METHODS Developmental, physical, and ophthalmologic assessments were completed on both DG groups. RBC gal-1-p and urine galactitol were monitored during the follow-up visits in every child with DG galactosemia. Gal-1-p, urine galactitol, liver function tests, and FSH were tested at the time of study visit. RESULTS The groups had statistically significant differences on RBC gal-1-p and urine galactitol at the 2 week, 1 month, 6 month, and 1 year time points. There was no statistical difference of gal-1-p or urine galactitol in group-I and -II at the time of study. The groups had statistically significant differences on adaptive scores, but not on language or IQ. None of the DG subjects had abnormal liver function at the time of diagnosis or the study visit. The FSH levels were normal. There were no statistically significant relationships between the first year metabolic values and developmental outcomes. CONCLUSIONS The data presented here indicate that clinical and developmental outcomes in DG galactosemics are good regardless of any diet changes.

Review of miglustat for clinical management in Gaucher disease type 1.

Gaucher disease is a progressive lysosomal storage disorder caused by the deficiency of glucocerebrosidase, and characterized by intralysosomal storage of glucosylceramide that leads to dysfunction in multiple organ systems. Intravenous enzyme replacement with imiglucerase is the accepted standard for treatment of symptomatic patients and has been effective in reducing many of the signs and symptoms of type I Gaucher disease in the majority of patients without serious adverse effects. An alternative therapeutic approach is substrate reduction therapy with N-butyldeoxynojirimycin (NB-DNJ) (miglustat; Zavesca®), an imino sugar that reversibly inhibits glucosylceremide synthase and reduces intracellular storage of glucosylceramide. Miglustat was recently approved in Europe and the United States for symptomatic patients with mild to moderate clinical manifestations for whom enzyme replacement therapy is not an option. This review article discusses the results of clinical studies and use of miglustat as a therapeutic agent in patients with type I Gaucher disease.

Argininosuccinate lyase deficiency: Longterm outcome of 13 patients detected by newborn screening

Argininosuccinate lyase deficiency is a urea cycle disorder which can present in the neonatal period with hyperammonemic encephalopathy, or later in childhood with episodic vomiting, growth and developmental delay. Abnormal hair, hepatomegaly, and hepatic fibrosis are unique features of this disorder. Twelve patients with argininosuccinate lyase deficiency were ascertained between 4 and 6 weeks of age by urine amino acid screening. One infant in a previously identified family was diagnosed shortly after birth. Diagnosis was confirmed by enzyme assay in red blood cells and/or skin fibroblasts. At the time of last follow-up, patients had been followed for 13-33 years. All patients were asymptomatic at detection, 7 had slightly increased blood ammonia, and all were initially treated with low-protein diet. Utilization of (14)C-citrulline by intact skin fibroblasts measured by (14)C incorporation into macromolecules was 74-135% of the control mean for 7 of the 8 patients studied. Nine patients had normal development, 4 had learning disability, 6 had EEG abnormalities, 3 had seizure disorder. None had any episodes of hyperammonemic coma. None had hepatomegaly. Patients detected by screening had higher enzyme activity measured by the (14)C-citrulline incorporation assay than comparison groups of patients with neonatal-onset and with late-onset detected by clinical disease. The ability to utilize (14)C-citrulline by intact fibroblasts seems to correlate with clinical outcome and may have prognostic value. It is likely that early diagnosis and treatment contributed to the relatively mild clinical course of the study group.

Development of a newborn screening follow-up algorithm for the diagnosis of isobutyryl-CoA dehydrogenase deficiency

Purpose: Isobutyryl-CoA dehydrogenase deficiency is a defect in valine metabolism and was first reported in a child with cardiomyopathy, anemia, and secondary carnitine deficiency. We identified 13 isobutyryl-CoA dehydrogenase–deficient patients through newborn screening due to an elevation of C4-acylcarnitine in dried blood spots. Because C4-acylcarnitine represents both isobutyryl- and butyrylcarnitine, elevations are not specific for isobutyryl-CoA dehydrogenase deficiency but are also observed in short-chain acyl-CoA dehydrogenase deficiency. To delineate the correct diagnosis, we have developed a follow-up algorithm for abnormal C4-acylcarnitine newborn screening results based on the comparison of biomarkers for both conditions.Methods: Fibroblast cultures were established from infants with C4-acylcarnitine elevations, and the analysis of in vitro acylcarnitine profiles provided confirmation of either isobutyryl-CoA dehydrogenase or short-chain acyl-CoA dehydrogenase deficiency. Isobutyryl-CoA dehydrogenase deficiency was further confirmed by molecular genetic analysis of the gene encoding isobutyryl-CoA dehydrogenase (ACAD8). Plasma acylcarnitines, urine acylglycines, organic acids, and urine acylcarnitine results were compared between isobutyryl-CoA dehydrogenase– and short-chain acyl-CoA dehydrogenase–deficient patients.Results: Quantification of C4-acylcarnitine in plasma and urine as well as ethylmalonic acid in urine allows the differentiation of isobutyryl-CoA dehydrogenase–deficient from short-chain acyl-CoA dehydrogenase–deficient cases. In nine unrelated patients with isobutyryl-CoA dehydrogenase deficiency, 10 missense mutations were identified in ACAD8. To date, 10 of the 13 isobutyryl-CoA dehydrogenase–deficient patients remain asymptomatic, two were lost to follow-up, and one patient required frequent hospitalizations due to emesis and dehydration but is developing normally at 5 years of age.Conclusion: Although the natural history of isobutyryl-CoA dehydrogenase deficiency must be further defined, we have developed an algorithm for rapid laboratory evaluation of neonates with an isolated elevation of C4-acylcarnitine identified through newborn screening.

Very Long-Chain Acyl-CoA Dehydrogenase Deficiency in a Patient with Normal Newborn Screening by Tandem Mass Spectrometry

Very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) can be detected through newborn screening with tandem mass spectrometry. We report a patient who died as a result of severe brain injury due to hypoglycemia. Newborn screening was normal. Postmortem enzyme analysis and molecular testing confirmed the diagnosis of VLCADD.