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)

Standardized cognitive, behavioral, and neuroanatomical data are presented on 2 unrelated boys with the FRAXE (FMR2) GCC expansion mutation. In the context of normal IQ, both boys had a history of developmental delay, including significant problems with communication, attention, and overactivity. Additionally, one child was diagnosed with autistic disorder. Data from these 2 cases are compared to analogous information from previous reports about individuals with the FRAXE or FRAXA (FMR1) mutation. These comparisons support the idea that FRAXE is associated with nonspecific developmental delay and possibly high-functioning autism.
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PMID:Cognitive, behavioral, and neuroanatomical assessment of two unrelated male children expressing FRAXE. 903 11

We determined the CGG repeat length and AGG interruptions in the FMR1 gene in normal Chinese subjects and patients with infantile autism and mild mental retardation. Genomic DNA was investigated by PCR and Southern hybridisation for CGG repeat number and PCR with Mnl I restriction analysis for AGG interruption. Both the normal subjects and the patients with autism have 53 CGG repeats in FMR1, and the majority have two interspersed AGG. Our normal Chinese subjects have a similar number of interspersed AGG as other populations. When compared with the normal subjects, the autism patients have less AGG interruptions and a different pattern of AGG distribution. There was a significant difference in the CGG configurations between normal subjects and patients with autism. The latter had less interspersed AGG, as in fragile X patients, but they did not have fragile X. A study on mentally retarded patients with no infantile autism should also be carried out to ascertain whether mental retardation alone may have contributed to such AGG pattern.
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PMID:CGG repeat interruptions in the FMR1 gene in patients with infantile autism. 980 79

Taxonomic features of fragile X syndrome (FXS) associated with the fragile X mutation have evolved over several decades. Males are more severely impacted cognitively than females, but both show declines in IQ scores as they age. Although many males with FXS exhibit autistic-like features, autism does not occur more frequently in males with FXS than among males with mental retardation (MR). FXS is caused by inactivation of the FMR1 gene located on Xq27.3. FMRP, the protein produced by FMR1, has been detected in most organs and in brain. In cells, it is located primarily in cytoplasm and contains motifs found in RNA-binding proteins. The FMRP N-terminal contains a functional nuclear localization signal which permits the protein to shuttle between cytoplasm and nucleus. FMR1 knockout mice show subtle behavioral and visual-spatial difficulties. Analysis of their brain tissue suggests absence of FMRP impairs synaptic maturation. Individuals with the fragile premutation produce FMRP, and the phenotype associated with the premutation has been controversial. However, there seems to be a higher incidence of premature ovarian failure in women with the premutation than is found in the general female population. This may be related to unusual increases in mRNA levels in premutation carriers.
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PMID:FMR1 gene and fragile X syndrome. 1118 Feb 23

Evidence from the high male to female ratio of individuals with autism as well as suggestive linkage data have implicated the possible involvement of X chromosomal loci in the aetiology of autism. Studies of the FMR1 gene on Xq27 have shown that occasionally individuals, and particularly females, with the [CGG] repeat expansion and methylation mutation may present with autistic symptoms. However, molecular studies suggest that such mutations are not a major cause of autism. Previously, we have screened autism probands for mutations in regions of the FMR1 gene downstream of the [CGG] repeat and identified an intronic variant in the FMR1 gene, IVS10 + 14C-T, which was present at a significantly higher frequency in autistic individuals compared to controls individuals. We have now investigated this variant in a further 136 autism families and 186 control individuals. We have established that the variant is significantly more frequent among East Asian individuals within our affected and control groups (P < 0.0001) and although we observed a trend of higher transmission frequency of the rare allele to affected individuals, there was no significant evidence in either family-based or case/control association studies for this variant in autism (P > 0.05).
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PMID:Association and transmission analysis of the FMR1 IVS10 + 14C-T variant in autism. 1475 44

Fragile X syndrome (FXS) is the most common single gene (FMR1) disorder affecting cognitive and behavioral function in humans. This syndrome is characterized by a cluster of abnormalities including lower IQ, attention deficits, impairments in adaptive behavior and increased incidence of autism. Here, we show that young males with FXS have profound deficits in prepulse inhibition (PPI), a basic marker of sensorimotor gating that has been extensively studied in rodents. Importantly, the magnitude of the PPI impairments in the fragile X children predicted the severity of their IQ, attention, adaptive behavior and autistic phenotypes. Additionally, these measures were highly correlated with each other, suggesting that a shared mechanism underlies this complex phenotypic cluster. Studies in Fmr1-knockout mice also revealed sensorimotor gating and learning abnormalities. However, PPI and learning were enhanced rather than reduced in the mutants. Therefore, these data show that mutations of the FMR1 gene impact equivalent processes in both humans and mice. However, since these phenotypic changes are opposite in direction, they also suggest that murine compensatory mechanisms following loss of FMR1 function differ from those in humans.
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PMID:Sensorimotor gating abnormalities in young males with fragile X syndrome and Fmr1-knockout mice. 1498 23

Fragile X syndrome is one of the most common causes of mental retardation in males, and patients with fragile X syndrome occasionally develop autism. It is usually caused by an expansion of the trinucleotide repeat in the 5'-untranslated region of the FMR1 gene, but in a small number of patients deletions and point mutations have been identified. We screened all 17 exons of the FMR1 gene for mutations in 90 autistic or mentally retarded children using polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis. No mutations were found in 76 male patients. However, one female patient was heterozygous for a normal allele and a mutant allele with an A to C substitution at nucleotide 879 in exon 9. This mutation was not found in 50 controls. Reverse transcription-PCR revealed that a large proportion of the mutant transcripts were spliced aberrantly, causing premature termination of the protein synthesis. Although uncommon, point mutations in the FMR1 gene may be a cause of autism and mental retardation in Japanese patients.
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PMID:Single-strand conformation polymorphism analysis of the FMR1 gene in autistic and mentally retarded children in Japan. 1500 Feb 56

Fragile X syndrome (FXS) is the most common inherited cause of mental retardation. It is also one of the most common identifiable causes of Autism Spectrum Disorder (ASD). Carriers of FXS are often considered to be cognitively and behaviorally unaffected. However, we report here on six individuals in the premutation range who also have ASD. A comparison is made with five subjects in the premutation range who did not receive a diagnosis of ASD. The six individuals with ASD had a range of cognitive ability levels from no impairment to moderate retardation. Discussion includes the impact of molecular variables including lowered FMR1 protein and elevated FMR1 mRNA in addition to environmental factors leading to the complex neurodevelopmental disorder of ASD.
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PMID:Autistic spectrum disorder and the fragile X premutation. 1561 87

Fragile X syndrome (FXS) is caused by a full mutation expansion (>200 CGG repeats) in the FMR1 gene that results in a deficiency of the fragile X mental retardation protein. Although most individuals with the premutation (55-200 CGG repeats) are considered unaffected by FXS, recent case studies have documented children with the premutation who have cognitive deficits, behavioral problems, and/or autism spectrum disorders. The objective of this study was to compare the prevalence of autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD) symptoms in boys with the premutation who presented as probands, in brothers with the premutation who did not present as probands, and in normal brothers of premutation and/or full mutation carriers. Participants included 43 male children: 14 probands who presented to clinic, 13 nonprobands who were identified through cascade testing (routine genetic testing of family members after identification of a proband) and confirmed to have the premutation, and a control group of 16 male siblings of individuals with the fragile X premutation or full mutation who were negative for the FMR1 mutation. Participants came from 1 of 2 collaborative sites: University of California, Davis and La Trobe University in Australia. Parents completed the Conners' Global Index-Parent Version for assessing symptoms of ADHD and the Social Communication Questionnaire (SCQ) for identifying symptoms of ASD. Children who were in the ASD range on the SCQ (n = 13) underwent further evaluation with either the Autism Diagnostic Observation Schedule-Generic (n = 10) or the Autism Diagnostic Interview-Revised (n = 3). A final diagnosis of ASD included clinical assessment utilizing DSM-IV-TR criteria in addition to the standardized assessments. There was a higher rate of ASD in boys with the premutation presenting as probands (p < 0.001) or nonprobands (p < .04) compared with sibling controls without the premutation. In addition, probands had a significant increase in ADHD symptoms compared with controls (p < .0001). Of the probands, 93% had symptoms of ADHD and 79% had ASD. In the nonproband premutation group, 38% had symptoms of ADHD and 8% had ASD. Thirteen percent of sibling controls had symptoms of ADHD and none had ASD. IQ scores were similar in all 3 groups (p = .13), but the use of psychotropic medications was significantly higher in probands with the premutation compared with that in controls (p < .0001). Developmental problems have been observed in premutation carriers, particularly those who present clinically with behavioral difficulties. Although this study is based on a small sample size, it suggests that premutation carriers, even those who do not present clinically, may be at increased risk for an ASD and/or symptoms of ADHD. If the premutation is identified through cascade testing, then further assessment should be carried out for symptoms of ADHD, social deficits, or learning disabilities.
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PMID:Autism spectrum disorders and attention-deficit/hyperactivity disorder in boys with the fragile X premutation. 1668 80

Recent advances in our understanding of the clinical and molecular features of the fragile-X mental-retardation 1 gene, FMR1, highlight the importance of single-gene disorders. 15 years after its discovery, FMR1 continues to reveal new and unexpected clinical presentations and molecular mechanisms. Loss of function of FMR1 is a model for neurodevelopmental and behavioural disorders, including mental retardation, autism, anxiety, and mood instability. In addition, overexpression and CNS toxicity of FMR1 mRNA causes a late-onset neurodegenerative disorder, the fragile-X-associated tremor/ataxia syndrome (FXTAS). A similar mechanism is probably involved in premature ovarian failure, which affects up to 20% of female carriers of an altered FMR1 gene.
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PMID:Fragile-X syndrome and fragile X-associated tremor/ataxia syndrome: two faces of FMR1. 1716 1

Autism is a heterogeneous condition that is likely to result from the combined effects of multiple genetic factors interacting with environmental factors. Given its complexity, the study of autism associated with Mendelian single gene disorders or known chromosomal etiologies provides an important perspective. We used microarray analysis to compare the mRNA expression profile in lymphoblastoid cells from males with autism due to a fragile X mutation (FMR1-FM), or a 15q11-q13 duplication (dup(15q)), and non-autistic controls. Gene expression profiles clearly distinguished autism from controls and separated individuals with autism based on their genetic etiology. We identified 68 genes that were dysregulated in common between autism with FMR1-FM and dup(15q). We also identified a potential molecular link between FMR1-FM and dup(15q), the cytoplasmic FMR1 interacting protein 1 (CYFIP1), which was up-regulated in dup(15q) patients. We were able to confirm this link in vitro by showing common regulation of two other dysregulated genes, JAKMIP1 and GPR155, downstream of FMR1 or CYFIP1. We also confirmed the reduction of the Jakmip1 protein in Fmr1 knock-out mice, demonstrating in vivo relevance. Finally, we showed independent confirmation of roles for JAKMIP1 and GPR155 in autism spectrum disorders (ASDs) by showing their differential expression in male sib pairs discordant for idiopathic ASD. These results provide evidence that blood derived lymphoblastoid cells gene expression is likely to be useful for identifying etiological subsets of autism and exploring its pathophysiology.
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PMID:Genome-wide expression profiling of lymphoblastoid cell lines distinguishes different forms of autism and reveals shared pathways. 1751 20


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