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

The Lesch--Nyhan syndrome is a heritable disorder of the metabolism of uric acid in which behavioral manifestations are prominent and among the most provocative. The mutated or variant gene that determines this disorder is carried on the X chromosome. The disease is expressed exclusively in males. The molecular expression of the abnormal gene is in the completely defective activity of the enzyme hypoxanthine guanine phosphoribosyl transferase. As a result these patients overproduce uric acid and may develop early in life many of the clinical findings we associate with gout. They have in addition a variety of neurological abnormalities including mental retardation, spastic cerebral palsy, and involuntary, choreoathetoid movements. Involved patients have unusual, compulsive, aggressive behavior. Its most prominent but by no means exclusive feature is self-mutilation. The central feature in the management of this behavior is physical restraint. A number of practical procedures have been learned which facilitate the care and feeding of these patients. Promising new findings suggest that behavioral modification using extinction techniques and pharmacologic methods utilizing agents designed to increase the effective cerebral content of serotonin may each have a place in the management of behavior in this syndrome.
J Autism Child Schizophr 1976 Sep
PMID:Behavior in the Lesch--Nyhan syndrome. 108 51

Autism is a behavior disorder with genetic influences indicated from twin and family studies and from the co-occurrence of autism with known genetic disorders. Tuberous sclerosis complex (TSC) is a known genetic disorder with behavioral manifestations including autism. A literature review of these two disorders substantiates a significant association of autism and TSC with 17-58% of TSC subjects manifesting autism and 0.4-3% of autistic subjects having TSC. In initial data collected on 13 TSC probands and 14 autistic probands in our family study of autism and TSC, we identified 7 TSC subjects with autism. The seven TSC autistic probands are similar to non-TSC autistic probands on the Social and Communication domains of the Autism Diagnostic Inventory (ADI) (Le Couteur et al., 1989), but show fewer Repetitive Rituals. There are more male TSC probands with autism than female, despite an equal sex ratio among TSC probands. The TSC probands with autism have significantly more seizures and mental retardation than those without autism; however, the extent and etiology of associations require further study. Our preliminary findings suggest that a fruitful approach for delineating genetic influences in autism may come from further investigation of possible mechanisms underlying the association of autism and TSC.
J Autism Dev Disord 1992 Sep
PMID:Autism and tuberous sclerosis. 140 Jan 3

Recent reports in the literature have suggested a link between abnormalities of the cerebellar vermis and the behavioral syndrome of autism. Joubert syndrome is an autosomal recessive disorder characterized by partial or complete agenesis of the cerebellar vermis. However, there is little behavioral or psychiatric description of patients with this genetic condition. In this report, the neuropsychiatric characteristics of two children with Joubert syndrome are described in detail. One child met DSM-III-R diagnostic criteria for autistic disorder, while the other displayed autistic features. The female child displayed stereotypic behavior and impairments in social interaction and communication, had a markedly restricted repertoire of interests, and showed distress over changes in the environment. The male child demonstrated perseveration and preoccupation with sounds and textures, but had no abnormalities in social interaction. Although both children showed developmental disabilities, the degree of cognitive delay was significantly less than that described in previous reports of children with Joubert syndrome. This report adds to the growing body of evidence implicating cerebellar involvement in developmental disabilities and autistic behavior.
 ...
PMID:Autistic features in Joubert syndrome: a genetic disorder with agenesis of the cerebellar vermis. 837 28

The variability in behavioral manifestations of the fragile-X syndrome and the lack of a well-defined psychological profile require the attention of behavioral geneticists and other behavioral scientists. The association with autism suggests that the fra(X) may be responsible for a genetic subtype of autism. While the fragile-X syndrome is considered an X-linked disorder, several aspects of observed transmission patterns do not follow those of classical X-linked inheritance. In particular, the finding of genetic transmission via intellectually normal males is surprising and has important implications for genetic counseling, as well as for genetic models of the fragile-X syndrome. Reports on folic acid treatment are encouraging, but not conclusive. The mechanisms involved in the association between the fra(X) chromosome and its particular phenotype are still unknown. Current investigations applying advanced techniques in molecular biology are likely to provide insight into this unique genetic disorder.
 ...
PMID:The fragile-X syndrome. 329 15

The syndrome of autism has been documented as occurring in association with a wide variety of genetic conditions. Autistic patients with a coexistent genetic condition, however, are not behaviorally or developmentally distinct from autistic patients for whom there is no known etiology or associated organic condition. This report reviews the literature linking autistic behavior with genetic conditions. Genetic, neurodevelopmental, and neuropathological findings in three genetic conditions which frequently give rise to autism are presented in detail. On the basis of this review, two hypotheses are supported: autism is a behaviorally defined phenotype which arises from diverse causes of central nervous system (CNS) damage, and the autistic phenotype represents only one point along a continuum of psychological dysfunction resulting from CNS damage. Current theories of genetic influences on brain development are reviewed, with emphasis on the relationships among qualitative, quantitative, and temporal abnormalities of CNS maturation and behavioral dysfunction. A hypothesis of abnormal brain development resulting from dysfunctional myelination is proposed as a potential etiologic factor in autism.
 ...
PMID:Autism and genetic disorders. 381 72

The purpose of this study is to test the hypothesis that major affective and/or anxiety disorders are increased among relatives of autistic probands compared with controls. Among 36 families with an autistic child, 23 (64%) have a first degree relative diagnosed with major depressive disorder and 14 (39%) have a first degree relative diagnosed with social phobia. These rates are significantly greater than the 19% and 5%, respectively, found among 21 families with a child having a genetic condition, tuberous sclerosis complex, or a seizure disorder but no autism. The frequency of major depression among the 96 first degree relatives of autistic probands is 37.5% compared with 11.1% found among 45 relatives of control probands. The frequency of social phobia, 20.2%, is approximately 10 times more common than that found among the relatives of the control probands (2.4%). Elevated rates of both major depression and social phobia are found among parents and siblings in the families with an autistic child. Furthermore, 64% of parents affected with a major depression had the onset of the first depressive episode prior to the birth of the autistic child and all parents with social phobia had the onset of condition prior to the birth of the autistic child. Family patterns differ depending on the intellectual level of the autistic child; specifically, social phobia is significantly greater among the first degree relatives of non-retarded autistic probands than among relatives of individuals with autism and comorbid mental retardation.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Autism, affective disorders, and social phobia. 748 30

Autism is a poorly understood developmental disorder characterized by social impairment, communication deficits, and compulsive behavior. The authors review evidence from animal studies demonstrating that the nonapeptides, oxytocin and vasopressin, have unique effects on the normal expression of species-typical social behavior, communication, and rituals. Based on this evidence, they hypothesize that an abnormality in oxytocin or vasopressin neurotransmission may account for several features of autism. As autism appears to be a genetic disorder, mutations in the various peptide, peptide receptor, or lineage-specific developmental genes could lead to altered oxytocin or vasopressin neurotransmission. Many of these genes have been cloned and sequenced, and several polymorphisms have been identified. Recent gene targeting studies that alter expression of either the peptides or their receptors in the rodent brain partially support the autism hypothesis. While previous experience suggests caution in hypothesizing a cause or suggesting a treatment for autism, the available preclinical evidence with oxytocin and vasopressin recommends the need for clinical studies using gene scanning, pharmacological and neurobiological approaches.
 ...
PMID:Oxytocin, vasopressin, and autism: is there a connection? 995 61

Autism is a developmental disorder characterized by impaired social and communicative development, and restricted interests and activities. This article will argue that we can discover more about developmental disorders such as autism through demonstrations of task success than through examples of task failure. Even in exploring and explaining what people with autism find difficult, such as social interaction, demonstration of competence on contrasting tasks has been crucial to defining the nature of the specific deficit. Deficit accounts of autism cannot explain, however, the assets seen in this disorder; for example, savant skills in maths, music and drawing, and islets of ability in visuospatial tests and rote memory. An alternative account, reviewed here, suggests that autism is characterized by a cognitive style biased towards local rather than global information processing - termed 'weak central coherence'. Evidence that weak coherence might also characterize the relatives of people with autism, and form part of the extended phenotype of this largely genetic disorder, is discussed. This review concludes by considering some outstanding questions concerning the specific cognitive mechanism for coherence and the neural basis of individual differences in this aspect of information processing.
 ...
PMID:Autism: cognitive deficit or cognitive style? 1035 74

Males are at least four times more likely to develop autism than females. Among relatives with a broader autistic phenotype, males predominate too. Autism is a highly heritable disorder, yet genome scans have not revealed any predisposing loci on the sex chromosomes. A nongenetic explanation for male vulnerability, such as exposure to prenatal androgens, is unlikely for a variety of reasons. A novel genetic mechanism that resolves many of the outstanding difficulties is outlined here. The imprinted-X liability threshold model hypothesizes that the threshold for phenotypic expression of many autistic characteristics is influenced by an imprinted X-linked gene(s) that is protective in nature. Imprinted genes are known to play an important role in normal fetal and behavioral development. The gene is expressed only on the X-chromosome that is inherited from the father and raises the threshold for phenotypic expression. It is normally silenced when transmitted maternally. Because only females have a paternal X-chromosome, the threshold for phenotypic expression is higher in them than in males. Evidence for the existence of the genetic locus was found in a study of females with X-monosomy (Turner's syndrome) in which females had either a single paternal or maternal X-chromosome. Identifying the sites of action of this X-linked gene could lead to the discovery of autosomal loci that confer more directly a predisposition to autism.
 ...
PMID:Imprinting, the X-chromosome, and the male brain: explaining sex differences in the liability to autism. 1062 77

In an effort to delineate more homogeneous autism subgroups for genetic study, we evaluated 133 consecutive individuals referred to the University of Missouri Autism Center. Each index case underwent a diagnostic evaluation, including a clinical morphology examination, laboratory studies, brain MRI, EEG, and collection of historical, medical, and family data. The 71% (94/133) who fulfilled DSM-IV and CARS autism diagnostic criteria were included in this study. Six of 94 were diagnosed with a known genetic disorder. Of the remaining 88 with apparently "idiopathic autism," 58% (51/88) were phenotypically normal, 22% (19/88) were clearly abnormal, and for 20% (18/88) the clinical morphology examination was equivocal. The percentage of phenotypically abnormal individuals is higher than generally thought and disagrees with the perception that children with autism are usually normally formed. The phenotypically abnormal individuals were 10 times more likely to be diagnosed with a known genetic syndrome (21% vs. 2%) and were more than twice as likely (29% vs. 14%) to have structurally abnormal brain MRIs than the phenotypically normal propositi. Moreover, the male to female ratio correlated with the presence of physical anomalies. The total study group had a male to female ratio of 4.2:1; the morphologically normal subgroup, defined on the basis of a normal physical examination, had a sex ratio of 7.5:1 and the normal subgroup, defined on the basis of both a normal physical examination and a structurally normal brain by MRI had a 23:1 sex ratio. For the phenotypically abnormal subgroup, the sex ratio was 1.7:1. Since differences in sex ratio are presumably a reflection of differences in genetic constitution, we postulate that the phenotypically normal subgroup of individuals with "idiopathic autism" is genetically different from the phenotypically abnormal individuals and that differences in the sex ratio in different autism populations is one indicator of a population's genetic heterogeneity.
 ...
PMID:Value of a clinical morphology examination in autism. 1076 78


1 2 3 4 5 6 7 8 9 10 Next >>