Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004352 (autism)
 32,579 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Single-photon emission computed tomography (SPECT) of the brain has been used to define functional abnormalities in two groups of childhood behavior disorders: (1) a "primary" category in which there is exclusive or predominant presentation with cognitive and/or behavioral dysfunction and (2) encephalopathies, often defined etiologically at the biochemical or molecular level, in which clinical expression includes, but is not confined to, neural dysfunction. Radiopharmaceuticals available for such studies are manifold, but those used to date have been predominantly perfusion agents, eg, Xenon-133 (133Xe) and technetium-99m (99mTc) hexamethylpropylene amine oxime, and studies with [99mTc]bicisate are eagerly awaited. Xenon-133 studies require that the patient be in the field of view of the detector while the tracer is administered. This renders it difficult for a subject to perform cognitive and other exercises while being imaged, because the environment is quite foreign. On the other hand, the 99mTc-labeled perfusion agents permit a scintigraphic "snapshot" of regional cerebral blood flow during a behavioral event without having to have the patient under the imaging instrument. Thus, one can separate the administration of the radiotracer, which can be done under more controlled and physiological conditions, from the actual imaging. In addition, greater spatial resolution is achieved with the technetium-based agents. Currently, multidetector or dedicated annular crystal-type cameras are the preferred brain SPECT devices, and they are essential to applications such as cortical "activation mapping" or tomographic detection of receptor systems. Close attention to technical detail and standardization of the child's behavioral environment during the investigation are critical to a successful study. The relative advantages and disadvantages of qualitative versus semiquantitative analysis of imaging date are reviewed. Among primary behavioral disorders, 133Xe SPECT studies in attention deficit disorder-hyperactivity (ADHD) have suggested a pattern of hypoperfusion of striatal and periventricular structures with sensorimotor cortical hyperperfusion. This pattern is consistent with some neurophysiological models of the disorder. In cerebral palsy, perfusional abnormalities have paralleled clinical deficits and may offer information to help predict outcome. The important field of childhood affective disorders (schizophrenia, juvenile autism, depression, etc) remains largely unstudied with SPECT. Finally, representative examples of the use of SPECT to study perfusion in encephalopathies with behavioral expression (phenylketonuria, MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) syndrome, Wilson's disease, etc) are given.
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PMID:Brain single-photon emission computed tomography for behavior disorders in children. 837 98

A group of 12 children clinically presenting with hypotonia, intractable epilepsy, autism, and developmental delay, who did not fall into previously described categories of mitochondrial encephalomyopathy, were evaluated for mitochondrial respiratory enzyme activity levels, mitochondrial DNA, and mitochondrial structural abnormalities. Reduced levels in specific respiratory activities were found solely in enzymes with subunits encoded by mitochondrial DNA in seven of eight biopsied skeletal muscle specimens evaluated. Five cases exhibited increased levels of large-scale mitochondrial DNA deletions, whereas pathogenic point mutations previously described in association with mitochondrial encephalomyopathies were not found. Mitochondrial structural abnormalities were present in three of four patients examined. Our findings suggest that mitochondrial dysfunction, including extensive abnormalities in specific enzyme activities, mitochondrial structure, and mitochondrial DNA integrity, may be present in children with a clinical constellation including hypotonia, epileptic seizures, autism, and developmental delay. The acronym HEADD is presented here to facilitate pursuit of mitochondrial defects in patients with this clinical constellation after other causes have been excluded.
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PMID:Mitochondrial dysfunction in patients with hypotonia, epilepsy, autism, and developmental delay: HEADD syndrome. 1217 64

The A to G transition mutation at position 3260 of the mitochondrial genome is usually associated with cardiomyopathy and myopathy. One Japanese kindred reported the phenotype of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS syndrome) in association with the A3260G mtDNA mutation. We describe the first Caucasian cases of MELAS syndrome associated with the A3260G mutation. Furthermore, this mutation was associated with exercise-induced rhabdomyolysis, hearing loss, seizures, cardiomyopathy, and autism in the large kindred. We conclude that the A3260G mtDNA mutation is associated with wide phenotypic heterogeneity with MELAS and other "classical" mitochondrial phenotypes being manifestations.
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PMID:MELAS syndrome, cardiomyopathy, rhabdomyolysis, and autism associated with the A3260G mitochondrial DNA mutation. 2096 48