The neurobiology of infantile autism

Psychiatric illness and learning disability: a dual diagnosis

The prevalence of moderate to profound learning disability is roughly 3 per 1000 and of mild learning disability about 3 per hundred (Abramowicz & Richardson, 1975). There are estimated to be more than 120 million people with learning disability worldwide.

Minor physical anomalies in children with autism spectrum disorder

AIM

To investigate the rate and topological profile of minor physical anomalies (MPAs) (prenatal errors of morphogenesis) in a group of children with Autism Spectrum Disorder (ASD), in order to better set a temporal framing of embryological factors involved in the neurodevelopmental etiology.

METHOD

A new modified Waldrop scale and a mixed approach of computerized photogrammetry and classic anthroposcopy was used to detect the presence or absence of 41 MPAs in 24 children (mean age: 7 years; sex ratio: 22M:2F) with ASD and 24 healthy comparison subjects (mean age: 7 years; sex ratio: 19M:5F) selected with DSM IV and CARS.

RESULTS

We found that children with ASD presenting MPAs (n=23; 96%) had significantly higher rates of MPAs in four body areas (head, ears, mouth, hands); interestingly three of 41 MPAs best discriminated ASD groups from comparison subjects: abnormal head circumference, abnormal cephalic index, abnormal palate. Moreover, our results suggest that most MPAs occur predominantly after the first trimester of pregnancy.

CONCLUSIONS

These results support a prenatal neurodevelopmental model of the autism spectrum disorder.

Genotype and natural history in unrelated individuals with phenylketonuria and autistic behavior

We describe three unrelated individuals, two males (ages 35 and 9) and a female (age 8) presenting with late diagnosed phenylketonuria (PKU) and autistic behavior, all showing poor adhesion to the dietary treatment resulting in high plasmatic phenylalanine levels, particularly in the oldest subject. Clinical findings included hair hypopigmentation, microcephaly, severe mental retardation with absent development of verbal language and autistic symptoms in all three patients, whereas variable neurological signs such as seizures, spasticity, ataxia, aggressivity, and hyperactivity were individually found. Homozygosity for the IVS10nt11g/a (IVS10nt546) was found in all. This is the first report of molecular findings in subjects with PKU also presenting with autistic features. The authors discuss if this mutation is particularly involved in the association of autistic symptoms in untreated PKU individuals.

A case of pervasive developmental disorder with chromosomal translocation 1-4

We describe a 5-year-old girl with pervasive developmental disorder associated to chromosome 1-4 translocation, an association that has not been described in specialized literature until this moment.

Autistic features in a total population of 7-9-year-old children assessed by the ASSQ (Autism Spectrum Screening Questionnaire)

BACKGROUND

The prevalence of autism is reported to be on the rise worldwide. Change of diagnostic criteria and a broadening of the concept of autism have been mentioned as contributing factors. Further studies of general populations are needed. The present study assessed the distribution of autistic features in a total population of children 7-9 years of age, and explored the impact of age, gender, informant, and participation bias on symptom report.

METHODS

Teacher and parent forms of the Autism Spectrum Screening Questionnaire (ASSQ) were used in the "Bergen Child Study", a total population study of 9430 children aged 7-9 years. Completed teacher forms were returned for 97% and parent forms for 71% of the children. High-scorers were defined according to the ASSQ validation study by Ehlers, Gillberg, and Wing (1999).

RESULTS

The distribution of ASSQ scores was found to be almost continuous. Of the children with both a teacher and a parent form, 2.1% were defined as high-scorers. Children without parent informed consent (i.e., anonymous children) obtained significantly higher teacher scores than those who had questionnaires completed by both parent and teacher. Adjusting prevalence for the anonymous children, the prevalence of high-scorers was 2.7% of the total population. Age did not affect symptom scores. Boys scored higher and parents reported more symptoms, particularly in girls. Agreement between informants was low to moderate.

CONCLUSIONS

Autism symptoms are not uncommon in the general population of children. Our findings are consistent with the concept of autism as a spectrum. Non-responders had a higher load of autism symptoms than identified children, indicating that reports on the prevalence of autism in a responder group underestimate true prevalence. Large differences across informants suggested the need to gather information both from families and from schools when screening for autism spectrum disorders.

Chromosomal anomalies in individuals with autism: a strategy towards the identification of genes involved in autism

We review the different strategies currently used to try to identify susceptibility genes for idiopathic autism. Although identification of genes is usually straightforward in Mendelian disorders, it has proved to be much more difficult to establish in polygenic disorders like autism. Neither genome screens of affected siblings nor the large number of association studies using candidate genes have resulted in finding autism susceptibility genes. We focus on the alternative approach of 'positional cloning' through chromosomal aberrations in individuals with autism. In particular, balanced aberrations such as reciprocal translocations or inversions offer a unique opportunity, since only the genes in the breakpoint regions are candidate genes. This approach, in combination with others, is likely to produce results in the coming years.

Genetic and neurological evaluation in a sample of individuals with pervasive developmental disorders

With the aim of analyzing which complementary tests are relevant in the diagnostic evaluation of individuals with pervasive developmental disorders, a protocol of clinical and laboratory evaluation was applied in 103 outpatients. The protocol included chromosomal analysis, screening for inborn errors of metabolism, cytogenetic and molecular study of the FRAXA, FRAXE, and FRAXF mutations, EEG, SPECT, and magnetic resonance imaging study. Eighty-four subjects concluded the complementary tests and were classified either as having autism, atypical autism or Asperger syndrome according to the DSM-IV criteria. Sixteen individuals, all bellonging to the two autistic groups, presented genetic or enviromental factors that may have lead to the behavioral disorders, showing the importance of diagnostic evaluation in this group of conditions. Neuroimaging and EEG findings were non-specific and occurred in similar proportion among the groups, being considered of relative low significance in the diagnostic evaluation of individuals with pervasive developmental disorders.

Identification of indolyl-3-acryloylglycine in the urine of people with autism

HPLC analysis of the urine of autistic subjects indicated the presence of an unidentified component in greatly increased concentrations. We have reported the isolation of this component by HPLC and its identification. Mass spectrometry, NMR and UV spectroscopy identified the peak as corresponding to indolyl-3-acryloylglycine (IAG, 3), and this has been confirmed by an independent synthesis.

Fetal valproate syndrome and autism: additional evidence of an association

Autism has been described in association with a variety of medical and genetic conditions. We previously reported on a patient whose clinical phenotype was compatible with both fetal valproate syndrome (FVS) and autism. Here we present five additional patients with FVS and autism. In all five of our patients, there was evidence of cognitive deficits, manifestations of autism, and typical phenotypic characteristics of FVS. The association between this known teratogen and autism has both clinical and research implications.

Season of birth in autism: a fiction revisited

Variations of season of birth among autistic individuals were studied. The replicability of previously reported increases in birth rates in the months of March and August were examined in groups of individuals with autism or mental retardation (the comparison group). The sample was obtained from the Yale Child Study Center Developmental Disabilities Clinic and from the DSM-IV Autism/PDD field trial. Data were analyzed by applying the Jonckheere test of ordinal trend and the chi-square test, with Yates correction factor. With respect to March and August births, and with calculations based on the beginning and middle of the month, no significant seasonal effect was observed. Samples were subcategorized into verbal and mute groups, and again results failed to support the seasonality hypothesis.

Childhood autism in tuberous sclerosis

The article reports two cases of childhood autism in tuberous sclerosis (TS). Certain atypical features are highlighted. The probands did not show the common seizure types associated with either TS or autism. No ventricular dilatation, cerebral atrophy or temporal lobe involvement was evident. The high prevalence of childhood autism in TS probands with moderate to severe mental retardation has been emphasized.

A male with fetal valproate syndrome and autism

Fetal valproate syndrome (FVS) is characterized by minor craniofacial anomalies, major organ malformations, and developmental delay. We report on a patient who has a clinical phenotype compatible with both FVS and autism. The presence of an autistic disorder in a previously reported case of FVS and similar findings in our patient suggest that a relation between this known teratogen and autism may exist.

Autism and associated behavioral disorders: pharmacotherapeutic intervention

OBJECTIVE

To review the literature on autism and pervasive developmental disorders (PDDs) as well as their respective pharmacotherapies.

DATA SOURCES

An Index Medicus, MEDLINE, and bibliographic search of the literature pertaining to autism, PDDs, and respective treatments.

STUDY SELECTION

Because of the paucity of literature on the treatment of autism and PDDs, the selection of reported data for this review included both controlled and uncontrolled studies, as well as case reports and any other information reported in the literature on the treatment of these disorders.

DATA SYNTHESIS

Autism and PDDs are severe developmental disabilities defined by behavioral criteria. These disorders are lifelong in nature and present in varying severity of clinical manifestations. Behavioral manifestations of patients with autism include core deficits in social interaction, communication, and imaginative activities, with a restricted repertoire of activities and interests. The present understanding of the neurochemical basis of the disorder is limited. The role of pharmacotherapy in the management of autism and PDDs is to ameliorate behavioral symptoms that interfere with the patient's ability to participate in educational, social, work, and family systems. Agents that have shown positive clinical effects in the treatment of children with autism and PDDs are reviewed in this article.

CONCLUSIONS

Autism is a complex developmental disorder representing a heterogeneous group of individuals with similar symptomatologies and multiple biologic etiologies. Present pharmacotherapeutic intervention seeks to resolve behavioral symptoms. Treatment of autism and PDDs requires appropriate delineation of the behaviors and neurobiologic disorders associated with each patient. No single therapeutic agent, or combination thereof, is appropriate for the treatment of all children and adults with autism or PDDs.

Autism: fifty years on from Kanner

It is now 50 years since Leo Kanner first described autism as a distinctive pattern of symptoms in some children with severe developmental problems. Since then the assessment and diagnosis of children with pervasive disorders of development has been refined and much is known about the phenomenology and epidemiology. Autism is a biological disorder of the central nervous system (CNS) of unknown cause. It is associated with a number of organic disorders such as epilepsy and has comorbidity with other psychiatric disorders such as tic disorder. Cognitive abnormalities in social interactions, affect and language are present but there is still debate regarding which of these, if any, is the primary cognitive deficit. Special education and behavioral management has led to modest but important developmental improvement in many children with autism. Autism remains a life-long condition but patterns of symptoms change and skills develop from childhood into adult life.

Executive function and social communication deficits in young autistic children

Preschool-aged, autistic children were compared with both developmentally delayed children of similar non-verbal mental age and normally developing children of similar verbal skill on measures of executive function and social communication skills. Autistic children exhibited significantly more perseverative responses on a test of executive function when compared to both comparison groups. Autistic children also exhibited significantly fewer joint attention and social interaction behaviors. Moreover, a significant relationship was found between executive function skill and the two social communication skills, which was independent of group membership or verbal ability. Competing hypotheses to account for the relationship between executive function deficits and social communication deficits in autism are discussed.

Magnetic resonance imaging in autism: measurement of the cerebellum, pons, and fourth ventricle

Magnetic resonance imaging (MRI) research has suggested that autistic individuals have hypoplasia of cerebellar lobules VI and VII, the pons, and enlargement of the fourth ventricle. Using MRI we measured the mid-sagittal area of these structures in 15 high-functioning autistic males; 15 age- and IQ-comparable male volunteers (control group I); and 15 male volunteers comparable to cases on age and parental socioeconomic status (SES) (control group II). Using ratio measures, cerebellar lobules VI-VII were found to be smaller in autistic subjects than controls in group II but not those in group I. No differences were found after multivariate analysis adjusting for mid-sagittal brain area (MSBA), age, and IQ. The size of the pons and fourth ventricle did not differ between cases and controls, although autistic subjects were noted to have a significantly larger MSBA than subjects in either control group.

Causes and associations of severe and persistent specific speech and language disorders in children

Eighty-two school-age children with severe and persistent specific speech and language disorders were studied. 71 had specific developmental language disorders, three had structural malformations (cleft palate) and eight had disorders acquired after a period of normal language development, including five with Landau-Kleffner syndrome. The sex ratio was 3.8 boys to one girl. Nearly half had a family history of speech-language disorder, with one in 5.2 affected siblings. Aetiological factors were found in 26 per cent: 11 per cent prenatal, 3 per cent perinatal and 12 per cent postnatal. 21 per cent had had a seizure and 7 per cent had had seizures after the age of eight. 29 per cent were left-handed, 90 per cent were clumsy and 22 per cent first walked after 18 months. The complex origins of specific speech and language disorders are discussed.

Neuropsychiatric assessment of children with autism: a population-based study

Thirty-five children with autistic disorder and 17 with autistic-like conditions underwent an exhaustive neurobiological evaluation, and the findings were contrasted with those obtained from various comparison groups. Almost 90 per cent of the children with autistic disorder and autistic-like conditions had major indications of brain damage or dysfunction. Some of those who did not show such abnormalities had a first-degree relative with Asperger syndrome. The rate of abnormality was similar to that of severely mentally retarded children, but in excess of that of normal children. Within the autism group, abnormality rate did not correlate with degree of mental retardation. It is concluded that autism has multiple biological aetiologies and that autistic symptoms in a child should always prompt a thorough medical/neurobiological evaluation.

Pre- and perinatal factors in high-functioning females and males with autism

Pregnancy and delivery complications as indicated in medical records and maternal reports for 23 high-functioning autistic females and 23 high-functioning males of similar IQ and age were compared with those of 54 of their normally developing siblings. Autistic subjects of both sexes had higher non-optimality scores than their siblings. Much of this difference was accounted for by a higher incidence of firstborns and fourth- or later-borns in the autistic group. Of factors found in previous research with mentally handicapped, autistic samples, only estimated weeks of gestation greater than 42 occurred more often in autistic subjects than siblings. The only sex difference specific to the autistic group was that autistic males came from larger families than females. These data provide slight support for the contribution of nonspecific pre- and perinatal factors to other etiological bases of autism. It is proposed that pre- and perinatal factors may play less of a role in autism in high-functioning individuals than suggested in studies of autism associated with severe retardation.

Autism associated with marker chromosome

Six boys who all showed the combination of moderate-severe mental retardation, autistic behavior, and mild-moderate physical stigmatization are described. Muscular hypotonia, epilepsy, and kyphoscoliosis were associated features in several cases, as were extremes of short stature and low weight. A supernumerary chromosome was found in all six cases, and it appears that there may be a separate syndrome associated with partial trisomy of chromosome 15.

Autistic symptoms in children with infantile hydrocephalus

From a population-based series of children with Infantile Hydrocephalus (IH) 69 patients (mean age 11.7 years) were examined with respect to the occurrence of autistic symptoms. Autistic symptomatology was evaluated according to a modified short Swedish version of the so-called Autism Behavior Checklist. Sixteen of the 69 IH children (23%) reached a score which was considered indicative of autistic symptoms (AS) in the child. This group was compared with the remaining 53 IH children without autistic symptoms (non AS). Significant differences were found between these two groups with respect to aetiological and clinical data. In the AS group 44% were born preterm as compared to 9% in the non AS group. CT scan showed major abnormalities in 64% of the AS children while this was present in 28% in the non AS group. The occurrence of major neuroimpairments--epilepsy, mental retardation and cerebral palsy--was 50%, 88% and 50% in the AS group as compared to 9%, 23% and 19% respectively in the non AS group. It was concluded that the more severe the brain damage in children with IH the more likely that autistic symptomatology would ensue. This implies that specific neuropsychiatric services to these families are required.

Is autism more common now than ten years ago?

A total population study of children, aged 13 years and under, suggested that there has been an apparent rise in the frequency of autistic disorder and autistic-like conditions (excluding Asperger's syndrome) in one area of western Sweden over the last ten years. The frequency was 4.0/100,000 in 1980, 7.5/10,000 in 1984 and 11.6/10,000 in 1988 in the city of Göteborg. Even though the prevalence rates refer to slightly different age cohorts, it was concluded that the apparent increase is in part due to better detection, but also to new cases born to immigrant parents. Typical cases of autistic disorder accounted for 75% of cases, and 20% had normal or near-normal IQs.

Low field magnetic resonance imaging of the central nervous system in 15 children with autistic disorder

Fifteen children, 10 boys and 5 girls, with autistic disorder, were studied with low field magnetic resonance imaging (MRI). The age ranged from 2.7-13.1 years, with a mean of 8.3 years. All patients but one (who refused) had a normal CT scan of the C.N.S. The MRI investigation was performed during anaesthesia with a low field magnetic resonance imager. The cerebrum, cerebellum, and brain stem were examined. No pathological changes were found in any of the patients studied.

Infantile autism: diagnosis and treatment

This article reviews recent developments in the diagnosis and treatment of infantile autism. Autism is currently conceptualized as a behavioural syndrome with multiple biological aetiologies. A diagnosis of infantile autism implies that a thorough neurobiological investigation is called for. The core psychological deficit necessary and sufficient to cause central autism symptoms is gradually being defined. The multiple aetiologies of autism will lead to multiple treatment in the future. At the present stage structured education and behaviour modification provide the cornerstones of any treatment programme.