Time to harmonize mitochondrial syndrome nomenclature and classification: A consensus from the North American Mitochondrial Disease Consortium (NAMDC).

OBJECTIVE: To harmonize terminology in mitochondrial medicine, we propose revised clinical criteria for primary mitochondrial syndromes. METHODS: The North American Mitochondrial Disease Consortium (NAMDC) established a Diagnostic Criteria Committee comprised of members with diverse expertise. It included clinicians, researchers, diagnostic laboratory directors, statisticians, and data managers. The Committee conducted a comprehensive literature review, an evaluation of current clinical practices and diagnostic modalities, surveys, and teleconferences to reach consensus on syndrome definitions for mitochondrial diseases. The criteria were refined after manual application to patients enrolled in the NAMDC Registry. RESULTS: By building upon published diagnostic criteria and integrating recent advances, NAMDC has generated updated consensus criteria for the clinical definition of classical mitochondrial syndromes. CONCLUSIONS: Mitochondrial diseases are clinically, biochemically, and genetically heterogeneous and therefore challenging to classify and diagnose. To harmonize terminology, we propose revised criteria for the clinical definition of mitochondrial disorders. These criteria are expected to standardize the diagnosis and categorization of mitochondrial diseases, which will facilitate future natural history studies and clinical trials.

A Complexity Perspective on Narrative Identity Reconstruction in Mental Health Recovery.

The issue of complex nonlinear change processes is one of the least understood aspects of recovery and one of the most difficult to apply in recovery-oriented health care. The purpose of this article is to explore the recovery stories of 17 mental health peer support workers to understand their narrative identity reconstruction in recovery using a complexity perspective. Using the Life Story Model of Identity (LSMI), a narrative thematic analysis of interviews suggests that self-mastery as part of personal agency is an important component of participants' narrative identity reconstruction. Self-mastery is particularly evident in redemptive story turning points (positive outcome follows negative experience). A complexity perspective suggests that participants realized their adaptive capacity in relation to self-mastery as part of recovery and that its use at story turning points critically influenced their recovery journey. Further exploring self-mastery as adaptive growth in narrative identity reconstruction appears to be a fruitful research direction.

Intrathecal heparan-N-sulfatase in patients with Sanfilippo syndrome type A: A phase IIb randomized trial.

BACKGROUND: Sanfilippo syndrome type A (mucopolysaccharidosis type IIIA) is a lysosomal disorder wherein deficient heparan-N-sulfatase (HNS) activity results in the accumulation of heparan sulfate in the central nervous system and is associated with progressive neurodegeneration in early childhood. We report on the efficacy, pharmacokinetics, safety, and tolerability of intrathecal (IT) administration of recombinant human HNS (rhHNS) from a phase IIb randomized open-label trial. METHODS: Twenty-one patients, randomized 1:1:1 to rhHNS IT 45 mg administered every 2 weeks (Q2W), every 4 weeks (Q4W), or no treatment, were assessed for amelioration in neurocognitive decline as determined by the Bayley Scales of Infant and Toddler Development®, Third Edition. The primary efficacy goal was defined as ≤10-point decline (responder) in at least three patients in a dosing cohort after 48 weeks. Other efficacy assessments included adaptive behavioral function, assessments of cortical gray matter volume, and glycosaminoglycan (GAG) levels in urine. RESULTS: A clinical response to rhHNS IT was observed in three treated patients (two in the Q2W group, one in the Q4W group). Cerebrospinal fluid heparan sulfate and urine GAG levels were reduced in all treated patients. However, most secondary efficacy assessments were similar between treated patients (n = 14; age, 17.8-47.8 months) and untreated controls (n = 7; age, 12.6-45.0 months). Treatment-emergent adverse events that occurred with rhHNS IT were mostly mild, none led to study discontinuation, and there were no deaths. CONCLUSION: rhHNS IT treatment reduced heparan sulfate and GAG levels in treated patients. Though the primary neurocognitive endpoint was not met, important lessons in the design and endpoints for evaluation of cognitive and behavioral diseases resulted. TRIAL REGISTRATION: ClinicalTrials.govNCT02060526; EudraCT 2013-003450-24.

Improved cardiac outcomes with combined atenolol and diazepam intervention in seizure.

OBJECTIVE: Altered autonomic activity has been implicated in the development of cardiac dysfunction during seizures. This study investigates whether intervening in seizure progression with diazepam will reduce seizure-induced cardiomyopathy. Second, this study examines the hypothesis that combining atenolol with diazepam, as an intervention after seizure onset, will combat cardiac injury during status epilepticus. METHODS: Male Sprague-Dawley rats were implanted with electroencephalographic/electrocardiographic electrodes to allow simultaneous recordings during seizures induced by intrahippocampal (2 nmol, 1 µL) kainic acid (KA). Subcutaneous saline, atenolol (5 mg·kg-1 ), diazepam (5 mg·kg-1 ), or atenolol and diazepam (n = 12/group) were administered at 60 minutes post-KA and daily for 7 days, at which point echocardiography, susceptibility to aconitine-induced arrhythmias, and histology were evaluated. RESULTS: Seizure activity was associated with immediately increased heart rate, QTc interval, and blood pressure (BP; 10%-30% across indices). Seven days postseizure, saline-treated animals were found to have reduced left ventricular function, increased fibrotic scarring, and an elevated risk of aconitine-induced arrhythmias. Diazepam treatment significantly reduced cumulative seizure behaviors by 79% compared to saline-treated animals but offered no cardiac protection. Diazepam significantly raised BP (35%) and increased the risk of bigeminal arrhythmias (36%) compared to saline-treated animals. Atenolol administration, either alone or with diazepam, reduced heart rate, QTc interval, and BP back to control levels. Atenolol also preserved cardiac morphology and reduced arrhythmia risk. SIGNIFICANCE: Attenuation of seizure with diazepam offered no cardiac protection; however, coadministration of atenolol with diazepam prevented the development of seizure-induced cardiac dysfunction. This study demonstrates that atenolol intervention should be strongly considered as an adjunct clinical treatment to reduce cardiomyopathy during seizures.

Enzymatic testing sensitivity, variability and practical diagnostic algorithm for pyruvate dehydrogenase complex (PDC) deficiency.

Pyruvate dehydrogenase complex (PDC) deficiency is a major cause of primary lactic acidemia in children. Prompt and correct diagnosis of PDC deficiency and differentiating between specific vs generalized, or secondary deficiencies has important implications for clinical management and therapeutic interventions. Both genetic and enzymatic testing approaches are being used in the diagnosis of PDC deficiency. However, the diagnostic efficacy of such testing approaches for individuals affected with PDC deficiency has not been systematically investigated in this disorder. We sought to evaluate the diagnostic sensitivity and variability of the various PDC enzyme assays in females and males at the Center for Inherited Disorders of Energy Metabolism (CIDEM). CIDEM data were filtered by lactic acidosis and functional PDC deficiency in at least one cell/tissue type (blood lymphocytes, cultured fibroblasts or skeletal muscle) identifying 186 subjects (51% male and 49% female), about half were genetically resolved with 78% of those determined to have a pathogenic PDHA1 mutation. Assaying PDC in cultured fibroblasts in cases where the underlying genetic etiology is PDHA1, was highly sensitive irrespective of gender; 97% (95% confidence interval [CI]: 90%-100%) and 91% (95% CI: 82%-100%) in females and males, respectively. In contrast to the fibroblast-based testing, the lymphocyte- and muscle-based testing were not sensitive (36% [95% CI: 11%-61%, p=0.0003] and 58% [95% CI: 30%-86%, p=0.014], respectively) for identifying known PDC deficient females with pathogenic PDHA1 mutations. In males with a known PDHA1 mutation, the sensitivity of the various cell/tissue assays (75% lymphocyte, 91% fibroblast and 88% muscle) were not statistically different, and the discordance frequency due to the specific cell/tissue used for assaying PDC was 0.15±0.11. Based on this data, a practical diagnostic algorithm is proposed accounting for current molecular approaches, enzyme testing sensitivity, and variability due to gender, cell/tissue type used for testing, and successive repeat testing.

Lethal neonatal case and review of primary short-chain enoyl-CoA hydratase (SCEH) deficiency associated with secondary lymphocyte pyruvate dehydrogenase complex (PDC) deficiency.

Mutations in ECHS1 result in short-chain enoyl-CoA hydratase (SCEH) deficiency which mainly affects the catabolism of various amino acids, particularly valine. We describe a case compound heterozygous for ECHS1 mutations c.836T>C (novel) and c.8C>A identified by whole exome sequencing of proband and parents. SCEH deficiency was confirmed with very low SCEH activity in fibroblasts and nearly absent immunoreactivity of SCEH. The patient had a severe neonatal course with elevated blood and cerebrospinal fluid lactate and pyruvate concentrations, high plasma alanine and slightly low plasma cystine. 2-Methyl-2,3-dihydroxybutyric acid was markedly elevated as were metabolites of the three branched-chain α-ketoacids on urine organic acids analysis. These urine metabolites notably decreased when lactic acidosis decreased in blood. Lymphocyte pyruvate dehydrogenase complex (PDC) activity was deficient, but PDC and α-ketoglutarate dehydrogenase complex activities in cultured fibroblasts were normal. Oxidative phosphorylation analysis on intact digitonin-permeabilized fibroblasts was suggestive of slightly reduced PDC activity relative to control range in mitochondria. We reviewed 16 other cases with mutations in ECHS1 where PDC activity was also assayed in order to determine how common and generalized secondary PDC deficiency is associated with primary SCEH deficiency. For reasons that remain unexplained, we find that about half of cases with primary SCEH deficiency also exhibit secondary PDC deficiency. The patient died on day-of-life 39, prior to establishing his diagnosis, highlighting the importance of early and rapid neonatal diagnosis because of possible adverse effects of certain therapeutic interventions, such as administration of ketogenic diet, in this disorder. There is a need for better understanding of the pathogenic mechanisms and phenotypic variability in this relatively recently discovered disorder.

Succinyl-CoA synthetase (SUCLA2) deficiency in two siblings with impaired activity of other mitochondrial oxidative enzymes in skeletal muscle without mitochondrial DNA depletion.

Mutations in SUCLA2 result in succinyl-CoA ligase (ATP-forming) or succinyl-CoA synthetase (ADP-forming) (A-SCS) deficiency, a mitochondrial tricarboxylic acid cycle disorder. The phenotype associated with this gene defect is largely encephalomyopathy. We describe two siblings compound heterozygous for SUCLA2 mutations, c.985A>G (p.M329V) and c.920C>T (p.A307V), with parents confirmed as carriers of each mutation. We developed a new LC-MS/MS based enzyme assay to demonstrate the decreased SCS activity in the siblings with this unique genotype. Both siblings shared bilateral progressive hearing loss, encephalopathy, global developmental delay, generalized myopathy, and dystonia with choreoathetosis. Prior to diagnosis and because of lactic acidosis and low activity of muscle pyruvate dehydrogenase complex (PDC), sibling 1 (S1) was placed on dichloroacetate, while sibling 2 (S2) was on a ketogenic diet. S1 developed severe cyclic vomiting refractory to therapy, while S2 developed Leigh syndrome, severe GI dysmotility, intermittent anemia, hypogammaglobulinemia and eventually succumbed to his disorder. The mitochondrial DNA contents in skeletal muscle (SM) were normal in both siblings. Pyruvate dehydrogenase complex, ketoglutarate dehydrogenase complex, and several mitochondrial electron transport chain (ETC) activities were low or at the low end of the reference range in frozen SM from S1 and/or S2. In contrast, activities of PDC, other mitochondrial enzymes of pyruvate metabolism, ETC and, integrated oxidative phosphorylation, in skin fibroblasts were not significantly impaired. Although we show that propionyl-CoA inhibits PDC, it does not appear to account for decreased PDC activity in SM. A better understanding of the mechanisms of phenotypic variability and the etiology for tissue-specific secondary deficiencies of mitochondrial enzymes of oxidative metabolism, and independently mitochondrial DNA depletion (common in other cases of A-SCS deficiency), is needed given the implications for control of lactic acidosis and possible clinical management.

Three rare diseases in one Sib pair: RAI1, PCK1, GRIN2B mutations associated with Smith-Magenis Syndrome, cytosolic PEPCK deficiency and NMDA receptor glutamate insensitivity.

The National Institutes of Health Undiagnosed Diseases Program evaluates patients for whom no diagnosis has been discovered despite a comprehensive diagnostic workup. Failure to diagnose a condition may arise from the mutation of genes previously unassociated with disease. However, we hypothesized that this could also co-occur with multiple genetic disorders. Demonstrating a complex syndrome caused by multiple disorders, we report two siblings manifesting both similar and disparate signs and symptoms. They shared a history of episodes of hypoglycemia and lactic acidosis, but had differing exam findings and developmental courses. Clinical acumen and exome sequencing combined with biochemical and functional studies identified three genetic conditions. One sibling had Smith-Magenis Syndrome and a nonsense mutation in the RAI1 gene. The second sibling had a de novo mutation in GRIN2B, which resulted in markedly reduced glutamate potency of the encoded receptor. Both siblings had a protein-destabilizing homozygous mutation in PCK1, which encodes the cytosolic isoform of phosphoenolpyruvate carboxykinase (PEPCK-C). In summary, we present the first clinically-characterized mutation of PCK1 and demonstrate that complex medical disorders can represent the co-occurrence of multiple diseases.

Diagnosis pathway for patients with amyotrophic lateral sclerosis: retrospective analysis of the US Medicare longitudinal claims database.

BACKGROUND: Initial symptoms of amyotrophic lateral sclerosis (ALS) are often subtle and can delay diagnosis. This exploratory analysis was conducted to better characterize the pre-diagnosis pathway undertaken by patients with ALS in the US Centers for Medicare & Medicaid Services Medicare longitudinal claims database. METHODS: Quarterly Medicare claims data were analyzed to determine the pre-diagnosis pathway for an ALS patient cohort that included patients aged ≥ 65 years with ≥ 2 ALS claims (International Classification of Diseases, Ninth Revision, Clinical Modification code 335.20) between the first quarter of 2007 and the fourth quarter of 2009, and were enrolled in Medicare ≥ 2 years before the first ALS claim (diagnosis). A cohort of Medicare patients without claims for motor neuron diseases were identified for comparison. A subset of these patients with ≥ 3 years of claims data was included in a time to diagnosis analysis. Data extraction included the most common initial symptoms of ALS, the time from first ALS symptom to diagnosis, and the diagnostic procedures performed before the diagnosis of ALS. RESULTS: A total of 399 patients met the inclusion criteria and were included in the ALS cohort; 272 patients were included in the time to diagnosis cohort. Before the quarter of diagnosis, symptoms that were more frequently seen in the ALS cohort than the general Medicare cohort included muscle weakness, lack of coordination and speech/swallowing difficulties. Limb-onset ALS (74%) was more common than bulbar-onset ALS (17%). Median time to diagnosis for limb- and bulbar-onset patients was 2.5 years and 1.25 years, respectively. The most common tests conducted before the quarter of diagnosis included sensory and motor nerve conduction tests, imaging studies, and electromyography; however, a substantial number of patients did not receive any nerve conduction testing. Motor nerve conduction testing in patients with bulbar-onset ALS had the largest impact on time to diagnosis. CONCLUSIONS: This analysis describes a diagnostic delay for patients with ALS in the US Medicare population, similar to previous reports. The development of tools and ongoing education that can help to identify patients with ALS earlier in their disease course is needed.

Infection-triggered familial or recurrent cases of acute necrotizing encephalopathy caused by mutations in a component of the nuclear pore, RANBP2.

Acute necrotizing encephalopathy (ANE) is a rapidly progressive encephalopathy that can occur in otherwise healthy children after common viral infections such as influenza and parainfluenza. Most ANE is sporadic and nonrecurrent (isolated ANE). However, we identified a 7 Mb interval containing a susceptibility locus (ANE1) in a family segregating recurrent ANE as an incompletely penetrant, autosomal-dominant trait. We now report that all affected individuals and obligate carriers in this family are heterozygous for a missense mutation (c.1880C-->T, p.Thr585Met) in the gene encoding the nuclear pore protein Ran Binding Protein 2 (RANBP2). To determine whether this mutation is the susceptibility allele, we screened controls and other patients with ANE who are unrelated to the index family. Patients from 9 of 15 additional kindreds with familial or recurrent ANE had the identical mutation. It arose de novo in two families and independently in several other families. Two other patients with familial ANE had different RANBP2 missense mutations that altered conserved residues. None of the three RANBP2 missense mutations were found in 19 patients with isolated ANE or in unaffected controls. We conclude that missense mutations in RANBP2 are susceptibility alleles for familial and recurrent cases of ANE.

Use of MR cell tracking to evaluate targeting of glial precursor cells to inflammatory tissue by exploiting the very late antigen-4 docking receptor.

PURPOSE: To determine if glial precursor cells can be targeted to inflamed brain through overexpression of very late antigen-4 (VLA-4) and whether this docking process can be monitored with magnetic resonance (MR) cell tracking after intraarterial injection. MATERIALS AND METHODS: All experimental procedures were performed between August 2010 and February 2012 and were approved by the institutional animal care and use committee. Human glial precursor cells (hGPs) were transfected with VLA-4 and labeled with superparamagnetic iron oxide that contained rhodamine. A microfluidic adhesion assay was used for assessing VLA-4 receptor-mediated cell docking in vitro. A rat model of global lipopolysaccharide (LPS)-mediated brain inflammation was used to induce global vascular cell adhesion molecule-1 (VCAM-1) expression. hGPs were infused into the carotid artery in four animal cohorts (consisting of three rats each): rats that received VLA-4-naive hGPs but did not receive LPS, rats that received VLA-4-expressing hGPs but not LPS, rats that received VLA-4-naive hGPs and LPS, and rats that received VLA-4-expressing hGPs and LPS. MR imaging was performed at 9.4 T before and 1, 10, 20, and 30 minutes after injection. Brain tissue was processed for histologic examination. Quantification of low-signal-intensity pixels was performed with pixel-by-pixel analysis for MR images obtained before and after cell injection. RESULTS: With use of the microfluidic adhesion assay, cell binding to activated brain endothelium significantly increased compared with VLA-4-naive control cells (71.5 cells per field of view±11.7 vs 36.4 cells per field of view±3.3, respectively; P<.05). Real-time quantitative in vivo MR cell tracking revealed that VLA-4-expressing cells docked exclusively within the vascular bed of the ipsilateral carotid artery and that VLA-4-expressing cells exhibited significantly enhanced homing as compared with VLA-4-naive cells (1448 significant pixels±366.5 vs 113.3 significant pixels±19.88, respectively; P<.05). Furthermore, MR cell tracking was crucial for correct cell delivery and proper ligation of specific arteries. CONCLUSION: Targeted intraarterial delivery and homing of VLA-4-expressing hGPs to inflamed endothelium is feasible and can be monitored in real time by using MR imaging in a quantitative, dynamic manner.

Spectrum of neurological and survival outcomes in pyruvate dehydrogenase complex (PDC) deficiency: lack of correlation with genotype.

Pyruvate dehydrogenase complex (PDC) deficiency is a relatively common mitochondrial disorder that primarily presents with neurological manifestations and lactic acidemia. We analyzed the clinical outcomes and neurological features of 59 consented symptomatic subjects (27 M, 32 F), who were confirmed to have PDC deficiency with defined mutations in one of the genes of PDC (PDHA1, n = 53; PDHB, n = 4; DLAT, n = 2), including 47 different mutations, of which 22 were novel, and for whom clinical records and/or structured interviews were obtained. 39% of these subjects (23/59) have died. Of these, 91% (21/23) died before age 4 years, 61% (14/23) before 1 year, and 43% (10/23) before 3 months. 56% of males died compared with 25% of females. Causes of death included severe lactic acidosis, respiratory failure, and infection. In subjects surviving past 6 months, a broad range of intellectual outcomes was observed. Of 42 subjects whose intellectual abilities were professionally evaluated, 19% had normal or borderline intellectual ability (CQ/IQ ≥ 70), 10% had mild intellectual disability (ID) (CQ/IQ 55-69), 17% had moderate ID (CQ/IQ 40-54), 24% had severe ID (CQ/IQ 25-39) and 33% had profound ID (CQ/IQ<25). Assessment by parents was comparable. Of 10 subjects who reached age 12 years, 9 had had professional IQ assessments, and only 4 had IQs ≥ 70 (only 2 of these 4 had assessments after age 12 years). The average outcome for females was severe-to-profound ID, whereas that of males was mild-to-moderate ID. Of subjects for whom specific neurological data were available, the majority had hypotonia (89%), and hypertonia or mixed hyper-/hypotonia (49%) were common. Seizures (57%), microcephaly (49%), and structural brain abnormalities including ventriculomegaly (67%) and agenesis, dysgenesis, or hypoplasia of the corpus callosum (55%) were common. Leigh syndrome was found in only 35%. Structural brain abnormalities were more common in females, and Leigh syndrome was more common in males. In a subgroup of 16 ambulatory subjects >3.5 years in whom balance was evaluated, ataxia was found in 13. Peripheral neuropathy was documented in 2 cases but not objectively evaluated in most subjects. Outcomes of this population with genetically confirmed PDC deficiency are heterogeneous and not distinctive. Correlations between specific genotypes and outcomes were not established. Although more females survive, related to the prevalence of X-linked PDHA1 mutations, symptomatic surviving females are generally more severely impaired cognitively and have a different pattern of neurological impairment compared to males. Neonatal or infant onset of symptoms was associated with poor outcomes. Males with PDHA1 mutations and low fibroblast PDC activity were less likely to survive beyond infancy. Recurrence rate in siblings of subjects with PDHA1 mutation was less than 5%. Paradoxically, in this retrospective review, potential factors considered possibly relevant to development, such as in vitro PDC activity, specific mutations, use of ketogenic diets, supplements, or medications, were generally not confirmed to be significantly correlated with objective outcomes of survival or neuro-cognitive function. Therefore, the basis of variability of these outcomes remains largely undetermined.

High prevalence of overweight and obesity in females with phenylketonuria.

The primary treatment for phenylketonuria (PKU) is a low phenylalanine diet together with an amino acid-based, phenylalanine-free formula. Thus, PKU patients tend to consume a diet enriched in carbohydrates which could predispose to obesity. Studies in the 1980s and 1990s demonstrated that school-age phenylketonuria (PKU) patients have a higher mean body weight compared to a control population. However, no recent studies in the United States PKU population have examined whether this trend has persisted or whether adolescents are also affected. To investigate whether pediatric PKU populations (ages 2-20 years) in two major metropolitan areas of the United States (Cleveland, OH and Houston, TX) have a higher than expected percentage of overweight (BMI≥85th percentile) relative to the general population in the United States (NHANES), a retrospective chart review of PKU patients born between 1990 and 2008 and followed in Cleveland, OH (Rainbow Babies and Children's Hospital/University Hospitals Case Medical Center) and in Houston, TX (Texas Children's Hospital) was performed. Based on data from the U.S., 40% of pediatric PKU patients were overweight or obese. However, the percentage of overweight females (55%) and obese females (33%) is 1.8× and 2.1× higher respectively than expected based on comparison data from U.S. children. Further studies are necessary to identify potential strategies for prevention of excessive weight gain in children with PKU, especially in females.

Treatment of relapsing-remitting multiple sclerosis with high-dose cyclophosphamide induction followed by glatiramer acetate maintenance.

BACKGROUND: Previous studies have described stabilization of aggressive multiple sclerosis (MS) with one-time induction therapy with high-dose cyclophosphamide (HiCy). The long-term benefit of this stabilization followed by conventional therapy has not been explored. OBJECTIVE: The objective of this study was to evaluate the safety and clinical outcomes following treatment of relapsing-remitting MS with HiCy induction therapy followed by glatiramer acetate maintenance. METHODS: A retrospective review of a closely followed population of thirty two MS patients treated with HiCy (200mg/kg intravenous infusion over 4 days) followed by maintenance with glatiramer acetate was performed. RESULTS: Annualized relapse rate was reduced from 1.37 in the 2 years prior to treatment to 0.27 over a mean post-treatment follow-up period of 14 months (range 0.5-33.8). The projected probability of relapse-free survival at 2 years was 0.64 (95% CI 0.37-0.82). The projected probability of Expanded Disability Status Scale (EDSS) progression-free survival at 2 years was 0.77 (95% CI 0.43-0.92). The mean number of gadolinium-enhanced lesions was reduced from 0.86 (SD 1.6) at baseline to 0 at 12 months and 0.08 (SD 0.28) at 15-24 months. A total of 55% of patients had no evidence of disease activity in follow-up. Infectious complications occurred in 47% with no long-term morbidity and no deaths. CONCLUSIONS: Induction therapy with HiCy followed by long-term maintenance with glatiramer acetate is well tolerated in patients with MS, and appears to be efficacious in reducing the risk of relapse, disability progression, and new MRI lesions.

Human glial-restricted progenitors survive, proliferate, and preserve electrophysiological function in rats with focal inflammatory spinal cord demyelination.

Transplantation of glial progenitor cells results in transplant-derived myelination and improved function in rodents with genetic dysmyelination or chemical demyelination. However, glial cell transplantation in adult CNS inflammatory demyelinating models has not been well studied. Here we transplanted human glial-restricted progenitor (hGRP) cells into the spinal cord of adult rats with inflammatory demyelination, and monitored cell fate in chemically immunosuppressed animals. We found that hGRPs migrate extensively, expand within inflammatory spinal cord lesions, do not form tumors, and adopt a mature glial phenotype, albeit at a low rate. Human GRP-transplanted rats, but not controls, exhibited preserved electrophysiological conduction across the spinal cord, though no differences in behavioral improvement were noted between the two groups. Although these hGRPs myelinated extensively after implantation into neonatal shiverer mouse brain, only marginal remyelination was observed in the inflammatory spinal cord demyelination model. The low rate of transplant-derived myelination in adult rat spinal cord may reflect host age, species, transplant environment/location, and/or immune suppression regime differences. We conclude that hGRPs have the capacity to myelinate dysmyelinated neonatal rodent brain and preserve conduction in the inflammatory demyelinated adult rodent spinal cord. The latter benefit is likely dependent on trophic support and suggests further exploration of potential of glial progenitors in animal models of chronic inflammatory demyelination.

Proteomic assessment of a cell model of spinal muscular atrophy.

BACKGROUND: Deletion or mutation(s) of the survival motor neuron 1 (SMN1) gene causes spinal muscular atrophy (SMA), a neuromuscular disease characterized by spinal motor neuron death and muscle paralysis. Complete loss of the SMN protein is embryonically lethal, yet reduced levels of this protein result in selective death of motor neurons. Why motor neurons are specifically targeted by SMN deficiency remains to be determined. In this study, embryonic stem (ES) cells derived from a severe SMA mouse model were differentiated into motor neurons in vitro by addition of retinoic acid and sonic hedgehog agonist. Proteomic and western blot analyses were used to probe protein expression alterations in this cell-culture model of SMA that could be relevant to the disease. RESULTS: When ES cells were primed with Noggin/fibroblast growth factors (bFGF and FGF-8) in a more robust neural differentiation medium for 2 days before differentiation induction, the efficiency of in vitro motor neuron differentiation was improved from ~25% to ~50%. The differentiated ES cells expressed a pan-neuronal marker (neurofilament) and motor neuron markers (Hb9, Islet-1, and ChAT). Even though SMN-deficient ES cells had marked reduced levels of SMN (~20% of that in control ES cells), the morphology and differentiation efficiency for these cells are comparable to those for control samples. However, proteomics in conjunction with western blot analyses revealed 6 down-regulated and 14 up-regulated proteins with most of them involved in energy metabolism, cell stress-response, protein degradation, and cytoskeleton stability. Some of these activated cellular pathways showed specificity for either undifferentiated or differentiated cells. Increased p21 protein expression indicated that SMA ES cells were responding to cellular stress. Up-regulation of p21 was confirmed in spinal cord tissues from the same SMA mouse model from which the ES cells were derived. CONCLUSION: SMN-deficient ES cells provide a cell-culture model for SMA. SMN deficiency activates cellular stress pathways, causing a dysregulation of energy metabolism, protein degradation, and cytoskeleton stability.

Treatment of mitochondrial electron transport chain disorders: a review of clinical trials over the past decade.

While many treatments for mitochondrial electron transport (respiratory) chain disorders have been suggested, relatively few have undergone controlled clinical trials. This review focuses on the recent history of clinical trials of dichloroacetate (DCA), arginine, coenzyme Q(10), idebenone, and exercise in both primary (congenital) disorders and secondary (degenerative) disorders. Despite prior clinical impressions that DCA had a positive effect on mitochondrial disorders, two trials of diverse subjects failed to demonstrate a clinically significant benefit, and a trial of DCA in MELAS found a major negative effect of neuropathy. Arginine also has been used to treat MELAS with promising effects, although a controlled trial is still needed for this potentially toxic agent. The anti-oxidant coenzyme Q(10) is very widely used for primary mitochondrial disorders but has not yet undergone a controlled clinical trial; such a trial is now underway, as well as trials of the co-Q analogue idebenone for MELAS and LHON. Greater experience has accumulated with multi-center trials of coenzyme Q(10) treatment to prevent the progression of Parkinson disease. Although initial smaller trials indicated a benefit, this has not yet been confirmed in subsequent trials with higher doses; a larger Phase III trial is now underway. Similarly, a series of trials of idebenone for Friedreich ataxia have shown some benefit in slowing the progression of cardiomyopathy, and controlled clinical trials are now underway to determine if there is significant neurological protection. Uncontrolled trials of exercise showed an increase of exercise tolerance in patients with disorders of mitochondrial DNA, but did not selectively increase the percentage of normal mtDNA; a larger partially controlled trial is now underway to evaluate this possible benefit. In summary, none of the controlled trials so far has conclusively shown a benefit of treatment with the agents tested, but some promising therapies are currently being evaluated in a controlled manner. These experiences underscore the importance of controlled clinical trials for evaluation of benefits and risks of recommended therapies. Application of such clinical trials to future more effective therapies for mitochondrial disorders will require multi-center collaboration, organization, leadership, and financial and advocacy support.

Deletion at chromosomal band Xp22.12-Xp22.13 involving PDHA1 in a patient with congenital lactic acidosis.

We present a patient with congenital lactic acidosis, agenesis of the corpus callosum, and profound developmental delay. Assays of pyruvate dehydrogenase complex function were normal in lymphocytes, but decreased in fibroblasts. Sequencing of the PDHA1 gene did not reveal deleterious mutations, and BAC based microarray analysis did not reveal any chromosomal abnormality. However, gene dosage analysis with oligonucleotide-based chromosomal microarray revealed a deletion of Xp22.12-Xp22.13 involving complete deletion of PDHA1. This is the first report of a whole gene deletion of PDHA1 detected by oligonucleotide-based microarray.

Somatic mosaicism for PDHA1 mutation in a male with pyruvate dehydrogenase complex deficiency.

Pyruvate dehydrogenase complex deficiency is a clinically heterogeneous disorder. Most cases are due to mutations in an X-linked PDHA1 gene encoding the E1alpha subunit of the multienzyme complex. Females with mutations in the PDHA1 gene may be asymptomatic or have a milder phenotype as a result of skewed X-inactivation, while males are typically more severely affected. We report a case of PDHA1 mosaicism in a male patient who had a milder phenotype.

Establishing a consortium for the study of rare diseases: The Urea Cycle Disorders Consortium.

The Urea Cycle Disorders Consortium (UCDC) was created as part of a larger network established by the National Institutes of Health to study rare diseases. This paper reviews the UCDC's accomplishments over the first 6years, including how the Consortium was developed and organized, clinical research studies initiated, and the importance of creating partnerships with patient advocacy groups, philanthropic foundations and biotech and pharmaceutical companies.