Succinate in dystrophic white matter: A proton magnetic resonance spectroscopy finding characteristic for complex II deficiency

A deficiency of succinate dehydrogenase is a rare cause of mitochondrial encephalomyopathy. Three patients, 2 sisters and I boy from an unrelated family, presented with symptoms and magnetic resonance imaging signs of leukoencephalopathy. Localized proton magnetic resonance spectroscopy indicated a prominent singlet at 2.40ppm in cerebral and cerebellar white matter not present in gray matter or basal ganglia. The signal was also elevated in cerebrospinal fluid and could be identified as originating from the two equivalent methylene groups of succinate. Subsequently, an isolated deficiency of complex II (succinate:ubiquinone oxidoreductase) was demonstrated in 2 patients in muscle and fibroblasts. One of the sisters died at the age of 18 months. Postmortem examination showed the neuropathological characteristics of Leigh syndrome. Her younger sister, now 12 months old, is also severely affected; the boy, now 6 years old, follows a Milder, fluctuating clinical course. Magnetic resonance spectroscopy provides a characteristic pattern in succinate dehydrogenase deficiency

Refsum disease, peroxisomes and phytanic acid oxidation: a review

Refsum disease was first recognized as a distinct disease entity by Sigvald Refsum in the 1940s. The discovery of markedly elevated levels of the branched-chain fatty acid phytanic acid in certain patients marked Refsum disease as a disorder of lipid metabolism. Although it was immediately recognized that the accumulation of phytanic acid is due to its deficient breakdown in Refsum disease patients, the true enzymatic defect remained mysterious until recently. A major breakthrough in this respect was the resolution of the mechanism of phytanic acid alpha-oxidation in humans. In this review we describe the many aspects of Refsum disease from the clinical signs and symptoms to the enzyme and molecular defect plus the recent identification of genetic heterogeneity in Refsum diseas

Role of the immune system in autism spectrum disorders (ASD)

Background: The evidence based supports that multifactorial and complex immune interactions play a role in autism spectrum disorders (ASD), but contradictory findings are also reported. Objective: The aim of this selective review was to identify trends in the research literature on this topic, focusing on immunology and other aberrations with respect to the different ASD subtypes. Methods: This selective review is based on original and review articles written in English and identified in literature searches of PubMed. Results: Several studies have found that the risk of ASD is greater among children whose mothers suffered from autoimmune diseases while pregnant. Moreover, individuals with ASD show increased levels of antibodies that are specific for several specific proteins. Studies also show that mothers of children with ASD have antibodies against fetal brain proteins. There are also reports on the associations between increased levels of proinflammatory cytokines and ASD. Finally, infections in mothers during pregnancy are linked to an increased risk of ASD. Conclusion: We propose that the large inconsistencies in findings among studies in the field are due to differences in subdiagnoses among the included children with ASD. Well-phenotyped ASD samples are needed to understand the biological and immunological mechanisms underpinning ASD and its subdiagnoses. Future research should apply new strategies to scrutinize the link between ASD and changes in immune responsivity. Important new research avenues are to investigate the associations (a) between different ASD phenotypes and aberrations in (auto)immune pathways and (b) between reduced natural regulatory autoimmune responses during pregnancy, which are in turn associated with increased oxidative and nitrosative stress in maternal blood and putative detrimental effects in the offspring

Medium chain acyl-CoA dehydrogenase deficiency and fatal valproate toxicity

A boy with delayed psychomotor development, attention deficit disorder, and therapy-resistant epilepsy was treated with valproate. The patient died of liver failure after 4 months of valproate treatment. Postmortem investigation of cultured fibroblasts suggested medium chain acyl-CoA dehydrogenase deficiency, an unexpected finding since the boy had not presented typical manifestations of this disease. Because medium chain acyl-CoA dehydrogenase is an important enzyme in the beta-oxidation of fatty acids, our patient probably had a genetically reduced tolerance to valproate. This drug should be omitted in the treatment of seizures in patients with possible medium chain acyl-CoA dehydrogenase deficiency. (C) 1997 by Elsevier Science Inc