ABSTRACT
Clinical descriptions of 14 adults with mild autism are presented. Structured questionnaires, extensive medical and social histories, and mental status examinations were conducted independently by several clinicians who concurred with the diagnoses of autism. These 14 patients demonstrate (1) that mild forms of autism can remain undiagnosed into adulthood; (2) that developmental histories and patients' reports may not provide evidence of developmental delays and characteristic symptoms during childhood despite their presence at adult mental status examination; (3) that mild previously undetected autism should be considered in the differential diagnoses of perplexing adult patients.
Subject(s)
Autistic Disorder/diagnosis , Adult , Aged , Female , Humans , Male , Middle Aged , Psychiatric Status Rating Scales , Severity of Illness IndexABSTRACT
A complex segregation analysis of autism in 185 Utah families was carried out using the mixed model. The 209 affected individuals in these families represent nearly complete ascertainment of the autistic cases born in Utah between 1965 and 1984. The sibling recurrence risk for autism was 4.5% (95% confidence limits 2.8%-6.2%). Likelihoods were maximized for major-gene models, a polygenic model, a sibling-effect model, and a mixed model consisting of major-gene and shared-sibling effects. The analysis provided no evidence for major-locus inheritance of autism. Subdivision of the sample according to the probands' IQ levels showed that sibling recurrence risk did not vary consistently with IQ level. A segregation analysis of families in which the proband had an IQ less than 50 also failed to provide evidence for a major locus. However, because of the etiologic heterogeneity of this disorder, genetic analysis of other meaningful subsets of families could prove informative.
Subject(s)
Autistic Disorder/genetics , Autistic Disorder/epidemiology , Female , Humans , Male , Models, Genetic , Prevalence , Psychological Tests , Statistics as Topic , Utah/epidemiologyABSTRACT
Twelve rare diseases known to cause CNS pathology were found in 26 (11%) of 233 autistic probands identified during a recent epidemiologic survey of Utah. These 26 probands had significantly lower mean IQs than the remaining patients (43 versus 60) but similar sex distribution and prevalence of abnormal EEGs and seizures. The rarity and diversity of these 12 diseases make it highly unlikely that they randomly occurred with autism. Their presence in this epidemiologic survey is the most compelling evidence to date to support the hypothesis that different diseases producing different types of CNS pathology can play an etiologic role in autism.
Subject(s)
Autistic Disorder/epidemiology , Central Nervous System Diseases/epidemiology , Adult , Autistic Disorder/etiology , Brain Diseases/complications , Brain Diseases/diagnosis , Brain Diseases/epidemiology , Central Nervous System Diseases/complications , Central Nervous System Diseases/diagnosis , Child , Comorbidity , Electroencephalography , Epilepsy/complications , Epilepsy/diagnosis , Epilepsy/epidemiology , Female , Humans , Intelligence Tests , Male , Utah/epidemiologyABSTRACT
In a recent epidemiologic survey conducted in Utah, 241 autistic patients (DSM-III criteria) were found. Medical records of 233 autistics were surveyed for the presence of 36 potentially pathologic prenatal, perinatal, and postnatal factors. These results were compared with those of an identical survey of 62 of their nonautistic siblings, with the results of four previously published surveys, and with normative data. No potentially pathologic factor or group of factors occurred significantly more frequently among the autistic patients. Also, previous observations of significant differences in the occurrence of certain factors in the histories single vs multiple siblings with autism were not confirmed, with the exception of increased viral-type illness during gestation in single-incidence cases. Thus, the etiology of the brain pathology that characteristically disrupts normal development and produces the syndrome of autism remains obscure. Other data from the epidemiologic survey, however, suggest that the role of genetic factors needs to be explored further.
Subject(s)
Autistic Disorder/epidemiology , Apgar Score , Autistic Disorder/etiology , Delivery, Obstetric , Epidemiologic Methods , Family , Female , Gestational Age , Humans , Infant, Newborn , Male , Maternal Age , Perinatology , Pregnancy , Pregnancy Complications , UtahABSTRACT
To assess familial aggregation of autism, 86 autistic subjects were linked to the Utah Genealogical Database. Kinship coefficients were estimated for all possible pairs of autistic subjects and then averaged. Fifty replicate sets of matched control subjects (86 members in each set) were drawn randomly from the database, and the average kinship coefficient was computed for all possible pairs of individuals in each set. The average kinship coefficient for the autistic subjects was approximately 1/1,000, while the average kinship coefficients for the 50 control groups ranged from 4/100,000 to 1.6./10,000. These results indicate a strong tendency for autism to cluster in families. When kinship was analyzed by specific degrees of relationship, it was shown that the familial aggregation of autism is confined exclusively to sib pairs and does not extend to more remote degrees of relationship. This finding indicates that a single-gene model is unlikely to account for most cases of autism.
Subject(s)
Autistic Disorder/genetics , Autistic Disorder/epidemiology , Cluster Analysis , Epidemiologic Methods , Female , Humans , Information Systems , Male , Utah/epidemiologyABSTRACT
The authors recently reported, in this journal, an epidemiologic survey of autism in Utah. Twenty (9.7%) of the 207 families ascertained had more than one autistic child. Analyses of these data revealed that autism is 215 times more frequent among the siblings of autistic patients than in the general population. The overall recurrence risk estimate (the chance that each sibling born after an autistic child will develop autism) is 8.6%. If the first autistic child is a male the recurrence risk estimate is 7%, and if a female 14.5%. These new recurrence risk estimates should be made available to all individuals who have autistic children and are interested in family planning.
Subject(s)
Autistic Disorder/epidemiology , Autistic Disorder/genetics , Birth Order , Epidemiologic Methods , Family Characteristics , Female , Genetic Counseling , Humans , Intelligence , Male , Religion , Risk Factors , Sex Ratio , UtahABSTRACT
The Wechsler Intelligence Scales, Wide Range Achievement Test, and the Shipley-Hartford Test were administered to 122 parents and 153 siblings of 62 autistic probands in Utah. Scores were distributed as expected within the published normative ranges for each scale. Parents' scores correlated with those of their nonautistic children, but neither parents' nor siblings' scores correlated with the IQ level of the autistic probands. These results do not confirm prior reports from England and the United States of a high rate of cognitive and learning problems in the siblings of autistic individuals, nor the aggregation of such problems in the siblings of probands with high or low levels of cognitive function.
Subject(s)
Autistic Disorder/genetics , Family , Psychological Tests , Achievement , Adult , Autistic Disorder/psychology , Child , Fathers/psychology , Female , Humans , Intellectual Disability/diagnosis , Intellectual Disability/genetics , Learning Disabilities/diagnosis , Learning Disabilities/genetics , Male , Mothers/psychology , Wechsler ScalesABSTRACT
The authors conducted an epidemiologic survey in Utah using a four-level ascertainment system, blind current diagnostic assessments, and DSM-III criteria. Of 483 individuals ascertained, 241 were diagnosed as having autism. The best estimate for the prevalence rate was 4 per 10,000 population. Autism was not associated with parental education, occupation, racial origin, or religion. Sixty-six percent of the autistic subjects scored below 70 on standardized IQ tests, and females scored proportionately lower than males. Twenty (9.7%) of 207 families had more than one autistic sibling, which supports the authors' previous finding that there may be a familial subtype of autism.
Subject(s)
Autistic Disorder/epidemiology , Adolescent , Adult , Autistic Disorder/genetics , Autistic Disorder/psychology , Child , Child, Preschool , Cross-Sectional Studies , Educational Status , Ethnicity , Female , Humans , Intelligence , Male , Occupations , Parents , Religion , Sex Factors , Social Class , UtahSubject(s)
Autistic Disorder/genetics , Adolescent , Adult , Autistic Disorder/diagnosis , Child , Child, Preschool , Female , Humans , Male , RiskSubject(s)
Autistic Disorder/etiology , Pregnancy Complications , Adolescent , Adult , Autistic Disorder/genetics , Child , Child, Preschool , Female , Humans , Labor, Obstetric , Male , Pregnancy , Uterine Hemorrhage/complicationsABSTRACT
We screened 183 autistic males for the fra(X) and found 24 (13.1%) to be positive. Adding the subjects of this study to those of 11 other surveys, of which 6 were positive and 5 were negative, a total of 614 autistic males have been screened. Overall 47 (7.7%) were positive. Based on this estimate and the prevalence of autism and fra(X), we estimate that 12.3% of fra(X) males are autistic. We have found that 17.3% of our fra(X) males were autistic and overall a 21.2% frequency has been reported, these higher figures are most likely due to biases in age and ascertainment. With an overall 7.7% frequency of fra(X) among autistic males and an estimated 12.3% of autism among fra(X) males, we conclude there is likely to be a significant association of fra(X) with autism. Because fra(X) appears to be the single most common cause of the condition, chromosomal testing is recommended for any autistic person with undiagnosed etiology.
Subject(s)
Autistic Disorder/genetics , Fragile X Syndrome/complications , Sex Chromosome Aberrations/complications , Autistic Disorder/epidemiology , Autistic Disorder/etiology , Fragile X Syndrome/epidemiology , Fragile X Syndrome/psychology , Genetic Testing , Humans , MaleABSTRACT
The authors ascertained 46 families with multiple incidences of autism (41 with two and five with three autistic probands). Classical segregation analyses revealed a maximum likelihood estimate of the segregation ratio of p = 0.19 +/- 0.07. This is not significantly less than 0.25, the expected value for autosomal recessive inheritance. However, it is significantly less than 0.50, the expected value for autosomal dominant inheritance. The polygenic threshold model was tested and rejected over a full range of values of heritability and ascertainment probability for these families. These results are most consistent with the hypothesis of autosomal recessive inheritance in this subset of 46 families with multiple incidences of autism.
Subject(s)
Autistic Disorder/genetics , Adolescent , Adult , California , Child , Child, Preschool , Diseases in Twins , Female , Genes, Dominant , Genes, Recessive , Genetic Linkage , Genetics, Population , Humans , Male , Models, Genetic , Pedigree , Pregnancy , Registries , Risk , Sex Factors , Twins, Dizygotic , X ChromosomeABSTRACT
The UCLA Registry for Genetic Studies in Autism was established in 1980 to test the hypothesis that genetic factors may be etiologically significant in subsets of patients. To date 61 pairs of twins have enrolled and 40 meet research diagnostic criteria for autism. The authors found a concordance for autism in these 40 pairs of 95.7% in the monozygotic twins (22 of 23) and 23.5% in the dizygotic twins (four of 17).
