Physical Anomalies Associated with Autism
We report the identification of six patients with 3q29 microdeletion syndrome. The clinical phenotype is variable despite an almost identical deletion size. The phenotype includes mild-to-moderate mental retardation, with only slightly dysmorphic facial features that are similar in most patients: a long and narrow face, short philtrum, and high nasal bridge. Autism, gait ataxia, chest-wall deformity, and long and tapering fingers were noted in at least two of six patients. Additional featuresmdashincluding microcephaly, cleft lip and palate, horseshoe kidney and hypospadias, ligamentous laxity, recurrent middle ear infections, and abnormal pigmentationmdashwere observed, but each feature was only found once, in a single patient. The microdeletion is sim1.5 Mb in length, with molecular boundaries mapping within the same or adjacent bacterial artificial chromosome (BAC) clones at either end of the deletion in all patients. The deletion encompasses 22 genes, including PAK2 and DLG1, which are autosomal homologues of two known X-linked mental retardation genes, PAK3 and DLG3. The presence of two nearly identical low-copy repeat sequences in BAC clones on each side of the deletion breakpoint suggests that nonallelic homologous recombination is the likely mechanism of disease causation in this syndrome.
We hypothesize that Duchenne muscular dystrophy and autism spectrum disorder/pervasive developmental disorder co-occur with a greater than random frequency. In this study, we set out to reject the hypothesis that Duchenne muscular dystrophy and autism spectrum disorder/pervasive developmental disorder co-occur no more often than expected by chance. Two index cases and six additional boys with concomitant Duchenne muscular dystrophy and autism spectrum disorder were identified in a muscular dystrophy clinic that approximates the total number of Duchenne muscular dystrophy boys (158) in the state of Massachusetts. The rate of prevalence (6 of 158) was compared with the prevalence rate of autism spectrum disorder in boys in the general population (1.6 in 1000). We rejected the hypothesis that Duchenne muscular dystrophy and autism spectrum disorder co-occurrence was likely to be explained by chance (P = .006). We identify a previously unrecognized association of Duchenne muscular dystrophy with autism spectrum disorder. Further work might elucidate the level of association between these two conditions, either at the genetic or at the protein level, and might clarify, at least partially, the neurobiologic mechanisms associated with autism spectrum disorder.
We conclude that 2D:4D ratio may be a possible marker for autism which could implicate prenatal testosterone in its aetiology.
Morphometry, the measurement of forms, is an ancient practice. Recently, evidence has grown to support the notion that aberrant neurodevelopment may play a role in the pathophysiology of autism. Is the body, like the brain, affected by abnormal development in these patients? The aim of this study was to evaluate body mass index (BMI) of children with infantile autism, by comparing the BMI of 117 children with infantile autism with the corresponding BMI percentiles in an age- and sex-matched reference population. The BMI distribution of the male, but not female, children with infantile autism was significantly lower than that of the age-matched reference population. There was no evidence that BMI was associated with intelligence or socioeconomic status among children with infantile autism.
Head circumference was not associated with language or executive functioning, nor was it related to verbal or nonverbal IQ. Head circumference was, however, correlated with discrepancies between verbal and nonverbal IQ scores, independent of absolute level of ability.
We found significant differences in ridge counts on the fingers and palms between the affected patients and their healthy controls, but these differences also existed between family members of autistic patients and healthy controls.
Children with autism have a relatively shorter index finger (2D) compared with their ring finger (4D). It is often presumed that the 2D:4D ratio is associated with fetal testosterone levels and that high fetal testosterone levels could play a role in the aetiology of autism. It is unknown whether this effect is specific to autism. In this study, 2D:4D ratios of 144 males aged 6 to 14 years (mean age 9y 1mo [SD 1y 11mo]) with psychiatric disorders were compared with those of 96 males aged 6 to 13 years from the general population (mean age 9y 1mo [SD 1y 10mo]). Psychiatric disorders were divided into autism/Asperger syndrome (n=24), pervasive developmental disorder-not otherwise specified (PDD-NOS; n=26), attention-deficit-hyperactivity disorder (ADHD)/oppositional defiant disorder (ODD; n=68), and anxiety disorders (n=26). Males with autism/Asperger syndrome (p<0.05) and ADHD/ODD (p<0.05) had significantly lower (though not significantly; p=0.52) ratios than males with an anxiety disorder, and males with autism/Asperger syndrome had lower ratios than those in the comparison group. These results indicated that higher fetal testosterone levels may play a role, not only in the origin of autism, but also in the aetiology of PDD-NOS and of ADHD/ODD. Males with anxiety disorders might have been exposed to lower prenatal testosterone levels.
Data from 10 sites of the NICHD/NIDCD Collaborative Programs of Excellence in Autism were combined to study the distribution of head circumference and relationship to demographic and clinical variables. Three hundred thirty-eight probands with autism-spectrum disorder (ASD) including 208 probands with autism were studied along with 147 parents, 149 siblings, and typically developing controls. ASDs were diagnosed, and head circumference and clinical variables measured in a standardized manner across all sites. All subjects with autism met ADI-R, ADOS-G, DSM-IV, and ICD-10 criteria. The results show the distribution of standardized head circumference in autism is normal in shape, and the mean, variance, and rate of macrocephaly but not microcephaly are increased. Head circumference tends to be large relative to height in autism. No site, gender, age, SES, verbal, or non-verbal IQ effects were present in the autism sample. In addition to autism itself, standardized height and average parental head circumference were the most important factors predicting head circumference in individuals with autism. Mean standardized head circumference and rates of macrocephaly were similar in probands with autism and their parents. Increased head circumference was associated with a higher (more severe) ADI-R social algorithm score. Macrocephaly is associated with delayed onset of language. Although mean head circumference and rates of macrocephaly are increased in autism, a high degree of variability is present, underscoring the complex clinical heterogeneity of the disorder. The wide distribution of head circumference in autism has major implications for genetic, neuroimaging, and other neurobiological research.
If there are 10 to 20 different autism genes, and if not everyone with autism has all of them, then the delineation of more homogeneous autism subgroups will be essential for successful gene finding.
There appear to be four phases to abnormal brain growth in autism: 1. slight undergrowth of the brain before birth compared to averages; 2. sudden and excessive increase in head size between 1-2 months and 6-14 months; 3. a gradual slowing in rate of brain growth between ages 2-4 so that by ages 4-5 brain size in autism reaches its near maximum (8 years sooner than that of non-autistic children); 4. a gradual decline in overall brain size extending from middle or late childhood to adults so that by those ages brain size in autism is not significantly different from the healthy average.
Macrocephaly is common in autism and usually is not present at birth. Rates of head growth may be abnormal in early and middle childhood in some (37%) children with autism. Macrocephaly does not define a homogeneous subgroup of autistic individuals according to clinical features.
The results agree with those of several previous studies, which have suggested that abnormalities of the ears are the general category of minor anomalies most associated with autism. Recent evidence regarding the embryological origin of autism suggests that the ear effects may be an important marker of the initiating events that lead to the disorder.
This study has shown an increase in minor physical abnormalities in subjects with sporadic schizophrenia, especially males, but not in familial schizophrenic patients or first degree relatives of either group. This work therefore supports the notion that abnormality of prenatal development is particularly implicated in sporadic schizophrenia.
The schizotypal personality disorder group showed more minor physical anomalies and dermatoglyphic asymmetries than the normal comparison group and higher cortisol levels than both of the other groups. Group differences in cortisol level were most pronounced at the beginning of the evaluation. Cortisol level and age were positively correlated.
MPAs may contribute to psychiatric impairment by influencing an individual's vulnerability to environmental risk factors for psychopathology. These suggestive findings are consistent with an emerging body of literature examining the role of biopsychosocial interactions in psychiatric disorders.
BACKGROUND: Longitudinal studies of head circumference growth in infants later diagnosed with autism are needed to understand the accelerated head growth in this disorder. METHODS: We analyzed longitudinal head circumference data from birth to 3 years in 28 children later diagnosed with autism spectrum disorder on the basis of individual growth curve analyses using hierarchical linear models. RESULTS: Head circumference Z scores relative to norms significantly increased in the autism sample from birth to 12 months, but this pattern did not persist beyond 12 months. Rather, the rate of change in head circumference from 12 to 36 months was not different from the normative sample. CONCLUSIONS: These results suggest that a period of exceptionally rapid head growth occurs during the first year of life in autism; after 12 months of age, the rate of head circumference growth decelerates relative to the rate during the first year of life. Studies of behavioral development in infants later diagnosed with autism suggest that the period of acceleration of head growth precedes and overlaps with the onset of behavioral symptoms, and the period of deceleration coincides with a period of worsening of symptoms in the second year of life.
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