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)

Recently, the human genome project has progressed and the responsible genes for many diseases have been discovered. Molecular diagnosis based on gene analysis techniques has developed. In this paper, the methods in molecular diagnosis were explained, taking as examples of several pediatric neurological diseases such as GM1- gangliosidosis, fragile X syndrome and congenital myotonic dystrophy. Next, we stressed the importance of the study on the gene function in related to the gene mutation. Finally the strategy to establish the molecular diagnosis of polygenic diseases, such as mental retardation and autism, was considered.
 ...
PMID:[The progress and strategy of molecular diagnosis for human genetic diseases]. 954 76

A large-scale cytogenetic study of the causes of intellectual disability (ID) in children from special schools and institutions was made in Taiwan between 1991 and 1996. The screening methods and the identification of subjects with ID consisted of both clinical evaluation (i.e. photographs, questionnaires on family, pre-, peri- and postnatal history, and hospital records, including IQ) and further laboratory studies for diagnosis (i.e. standard chromosome analysis, and if indicated, high-resolution banding, cytogenetic fragile-X study or molecular techniques). A total of 11,892 patients were enrolled in this study. After excluding the acquired causes of ID, such as infections and the sequelae of brain insults, or the well-known single-gene disorders and other multifactorial diseases, 4372 (36.8%) cumulative cases were recruited for karyotyping studies according to their phenotypes and medical records. Abnormal karyotypes were noted in 1889 children (43.2% of all selected children). Thus, the overall incidence of chromosomal aberrations in subjects with ID was estimated as 15.9%. Down's syndrome, the most common cause of ID, accounted for 82.4% of all patients with abnormal karyotypes. The causes of ID were considered to be prenatal in 55.2% (n = 6564) of cases, perinatal in 9.5% (n = 1130), postnatal in 3.3% (n = 392) and unknown in 32.0% (n = 3805) of cases. Two large groups were classified: (1) serious ID (37%), including profound, severe and moderate categories; and (2) mild ID (63%). The causes (pre-, peri- and postnatal, and unknown) in these two populations were: 70%, 10.5%, 5.4% and 14.1%, and 46.5%, 8.9%, 2.1% and 42.5%, respectively. Genetic causes accounted for 38.5% (n = 4578) of all cases in this study, including 1557 with Down's syndrome, 233 with fragile-X syndrome, 199 with other various chromosomal abnormalities (i.e. unbalanced translocation, supernumerary markers and structural rearrangements), 238 with a defined or presumed single-gene defect, and 98 with a recognized contiguous gene syndrome (Prader-Willi, 56; Angelman, 34; Williams, 5; and Kallmann, 3); 2120 cases had familial ID. Multiple anomalies of undefined pattern, but without chromosomal aberration, infantile autism, ID of normal phenotype or family history, were of the other categories. Patients with a single-gene disorder or chromosomal aberration, especially those with unbalanced translocated or rearranged chromosomes, had genetic counselling and family studies. Pre-screening with photographs and questionnaires may give a better costbenefit than blind mass cytogenetic studies for each individual with ID.
 ...
PMID:An epidemiological and aetiological study of children with intellectual disability in Taiwan. 961 97

Fragile X syndrome is the most common inherited form of mental disability, world-wide. Main clinical features are cognitive deficit, speech difficulties, delayed development, autism, and particular physical characteristics. The syndrome can be cytogenetically diagnosed by the expression of chromosome X fragile site at band Xq27.3. At molecular level, the cause of the syndrome is defined as an abnormal expansion of CGG trinucleotide repeats in the 5'UTR of the FMR-1 gene as well as hypermethylation at the proximal CpG island. Study of fragile X syndrome at Songklanagarind Hospital during May 1991-June 1996 was herein reported. A total of 287 blood samples of 260 unrelated families were cytogenetically examined by using lymphocyte culture method with 2-4 different treatments. Frequency of positive fragile X cases was found to be 7 in 260 (2.7%). Among relatives of the positive ones, 13 individuals were also positive. Other types of chromosome abnormalities were detected in 13 cases (5%). For molecular study, DNA samples were obtained from 97 cases. Investigation of CGG repeat expansion was performed by PCR method. Abnormal expansion was identified as full mutation (> 200 repeats) and premutation (> 50-200 repeats). The abnormalities were found in 14 individuals of 5 unrelated cases; 6 with full mutation and 8 with premutation. No molecular study on the two cytogenetic positive cases has been performed. In conclusion, a total of 50 individuals with fragile X abnormality has been documented: 18 affected cases and 32 carriers. Investigation of the remaining suspected members in positive families is in progress. The information and experience will lead to prevention of this genetic disease by prenatal diagnosis and elective abortion in Thailand.
 ...
PMID:The frequency of fragile X syndrome among selected patients at Songklanagarind Hospital during 1991-1996, studied by cytogenetic and molecular methods. 964 Jun 3

We studied 11 patients (9 males) with cytogenetic diagnosis of fragile X syndrome (FXS) with the purpose of investigating the neural circuitry involved in this condition. The ages ranged from 8 to 19. All the individuals presented large ears, elongated faces and autistic features. Ten patients had severe mental retardation. Attention disorder was found in 10 individuals. Electroencephalographic recordings were abnormal in 6 of 10 patients examined, showing focal epileptiform discharges predominantly in frontal and parietal areas. All patients underwent magnetic resonance imaging studies which were abnormal in 8 of them. The most important abnormalities were reduction of the cerebellar vermis and enlargement of the IV ventricle. Single photon emission computerized tomography (SPECT) was performed in 7 patients and was abnormal in all of them, the most frequent finding being a hypoperfusion of the inferior of the frontal lobes. Based on the clinical picture, neuropsychological findings and functional and structural imaging studies we suggest that FXS presents with a dysfunction involving a large area of the central nervous system: cerebellum-basal frontal regions-parietal lobes. The literature points to a disturbance involving the same neural circuitry in patients with autism.
 ...
PMID:Fragile X syndrome. Clinical, electroencephalographic and neuroimaging characteristics. 968 15

Unstable (CAG)n trinucleotide repeat microsatellites are hypothesized to cause schizophrenia. The (CAG)n microsatellite of dominant spinal cerebellar ataxia type 1 (SCA1) is a candidate schizophrenia gene. Autism results from expansions of (CGG)n and (GAA)n trinucleotide repeat stretches at fragile X syndrome (FRAXA), and the recessive Friedreich's ataxia (FA). Dominant ataxia genes may cause schizophrenia and recessive ataxia genes may cause autism. Syndromes with autism show purine synthesis defects (PSDs) and/or pigmentation defects (PDs). Autism is caused by very lengthy expansions of (CAG)n, (CGG)n and (GAA)n repeats, while schizophrenia results from much smaller (CAG)n and (CGG)n repeat expansions.
 ...
PMID:Expanded (CAG)n, (CGG)n and (GAA)n trinucleotide repeat microsatellites, and mutant purine synthesis and pigmentation genes cause schizophrenia and autism. 979

The relationship between the fragile X syndrome (FXS) and autism is reviewed. Shortly after the FXS was first described, it was noted that certain behaviors commonly found in afflicted individuals resemble certain features of autism. Research concerning a possible relationship between these conditions is summarized. The outcome of this research indicates that FXS is not a common cause of autism, although the number of individuals with FXS who meet diagnostic criteria for autism is higher than can be accounted for by chance. The major focus of this paper highlights that FXS is a well-defined neurogenetic disease that includes a cognitive behavioral phenotype, and has both a known biological cause and an increasing well-delineated pathogenesis. Autism is a behaviorally defined syndrome whose syndromic boundaries and biological causes are not known. These profound differences complicate comparisons and causal discussions. However, the behavioral neurogenetic information available about FXS suggests certain pathways for future research directed at elucidating the syndrome of autism.
J Autism Dev Disord 1998 Oct
PMID:Autism: the point of view from fragile X studies. 981 75

A sample of 57 boys with fragile X syndrome (fraX) between the ages of 24 and 133 months was rated using the Childhood Autism Rating Scale (CARS) to assess the extent to which autism and autistic features were evident in a young population. Fourteen subjects (approximately 25% of the sample) scored above the cutoff for autism, suggesting a relatively high incidence of autistic behavior. All but 2 of these 14 were in the mildly or moderately autistic range, however, and only a few items received severe ratings, suggesting that severe autism is relatively rare in fraX, at least during the early years. The CARS resulted in a continuum of autistic ratings in the fraX population, but no particular items on the CARS contributed disproportionately to autism ratings. A visual comparison of ratings on an autistic, non-fraX sample revealed similar profiles of ratings, suggesting that differentiating fraX and autism on the basis of CARS ratings is not likely. Within the fraX group, chronological age and socioeconomic status did not correlate with CARS ratings, but severity of delay was strongly related, such that more severely delayed children scored higher (more autistic) on the CARS.
J Autism Dev Disord 1998 Dec
PMID:Autistic behavior in young boys with fragile X syndrome. 993 36

Two independent and complementary studies were conducted to assess the ability of boys with fragile-X syndrome to recognize facial and emotional expressions. Both studies failed to find any specific deficits associated with fragile-X syndrome. The performance of the test group was comparable to the level of subjects with intellectual disability and subjects of average cognitive development matched for intellectual ability. This suggests that chronological age and intellectual level are unlikely to explain the findings. The results are discussed in the context of the controversy surrounding the relationship between autism and fragile-X syndrome. The findings are consistent with fragile-X individuals having a profile of social, communicatory and ritualistic disturbances, which in some ways may differ from those found in individuals who have more typical autistic spectrum disorders.
 ...
PMID:Face recognition and emotion perception in boys with fragile-X syndrome. 1003 Apr 45

The etiology of autism is complex, and in most cases the underlying pathologic mechanisms are unknown. Autism is a hetereogeneous disorder, diagnosed subjectively on the basis of a large number of criteria. Recent research has investigated genetics, in utero insults and brain function as well as neurochemical and immunological factors. On the basis of family and twin studies, there appears to be a genetic basis for a wide "autistic syndrome." About a quarter of cases of autism are associated with genetic disorders such as fragile X syndrome or with infectious diseases such as congenital rubella. Genetic studies have shown an association between autism markers of brain development such as 3 markers of the c-Harvey-ros oncogene and the homeobox gene EN2. In some cases, autism is associated with insults early in gestation, including thalidomide embryopathy. Autism may arise from abnormal central nervous system functioning, since most autistic patients have indications of brain dysfunction, and about half of them have abnormal electroencephalograms. Similarly, the pattern of evoked response potentials and conduction time is altered in autistic children. There is substantial evidence from neuroimaging studies that dysfunctions in the cerebellum and possibly the temporal lobe and association cortex occur in autistic symptoms. Neurochemical studies have investigated the role of serotonin, epinephrine and norepinephrine, since levels of these neurotransmitters are altered in autism, although other hypotheses implicate overactive brain opioid systems and changes in oxytocin neurotransmission. Autoimmunity may also play a role; antibodies against myelin basic protein are often found in children with autism, who also have increased eosinophil and basophil response to IgE-mediated reactions. In summary, the prevailing view is that autism is caused by a pathophysiologic process arising from the interaction of an early environmental insult and a genetic predisposition.
 ...
PMID:Etiology of infantile autism: a review of recent advances in genetic and neurobiological research. 1021 50

To determine whether there is an association of polymorphic variants of the serotonin transporter (5-HTT) gene-linked polymorphic region (5-HTTLPR) and autistic spectrum disorders, we analyzed the 5-HTTLPR genotypes of 72 autistic subjects, 11 fragile X syndrome patients with autistic behavior, 43 normal subjects, and 49 fragile X syndrome non-autistic subjects. The distribution frequency of 5-HTTLPR long allele (L) and the short allele (S) variants showed no differences between subjects. Our findings do not support the hypothesis that polymorphic 5-HTTLPR variants are a susceptibility factor for autistic disorders.
 ...
PMID:5-HTTLPR variants not associated with autistic spectrum disorders. 1036 90


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