Trends, perinatal characteristics, and medical conditions in pervasive developmental disorders

Congenital malformation and autism spectrum disorder: Insight from a rat model of autism spectrum disorder

AIMS AND OBJECTIVES:

The primary aim was an evaluation of the pattern of gross congenital malformations in a rat model of autism spectrum disorder (ASD) and the secondary aim was characterization of the most common gross malformation observed.

MATERIALS AND METHODS:

In females, the late pro-oestrous phase was identified by vaginal smear cytology, and then, they were allowed to mate at 1:3 ratio (male: female). Pregnancy was confirmed by the presence of sperm plug in the vagina and presence of sperm in the vaginal smear. In the ASD group, ASD was induced by injecting valproic acid 600 mg/kg (i.p.) to pregnant female rats (n = 18) on day 12.5 (single injection). Only vehicle (normal saline) was given in the control group (n = 12). After delivery, pups were grossly observed for congenital malformations until the time of sacrifice (3 months) and different types of malformations and their frequency were noted and characterized.

RESULTS:

In the ASD group, congenital malformation was present in 69.9% of the pups, whereas in the control group, it was 0%. Male pups were most commonly affected (90% in males vs. only 39.72% in female pups). The tail deformity was the most common malformation found affecting 61.2% pups in the ASD group. Other malformations observed were dental malformation (3.82%), genital malformation (3.28%) and paw malformation (1.1%). Hind limb paralysis was observed in one pup. The tail anomalies were characterized as per gross appearance and location of the malformation.

CONCLUSION:

In this well-validated rat model of ASD, congenital malformation was quite common. It seems screening of congenital malformations should be an integral part of the management of ASD, or the case may be vice versa, i.e., in the case of a baby born with a congenital deformity, they should be screened for ASD.

Low but increasing prevalence of autism spectrum disorders in a French area from register-based data

Register-based prevalence rates of childhood autism (CA), Asperger's syndrome (AS) and other autism spectrum disorders (ASD) were calculated among children aged 7 years old of the 1997-2003 birth cohorts, living in four counties in France. The proportion of children presenting comorbidities was reported. 1123 children with ASD were recorded (M/F ratio: 4.1), representing an overall prevalence rate of 36.5/10,000 children (95 % CI 34.4-38.7): 8.8/10,000 for CA (95 % CI 7.8-9.9), 1.7/10,000 for AS (95 % CI 1.3-2.3) and 25.9/10,000 for other ASD (95 % CI 24.2-27.8). ASD prevalence significantly increased (p < 0.0001) during the period under study. The proportion of children with an intellectual disability was 47.3 %, all other comorbidities were present in less than 5 % of the cases.

Childhood autism spectrum disorders with and without epilepsy: clinical implications

This prospective cross-sectional study compared 25 children with pervasive developmental disorder and epilepsy and 25 children having pervasive developmental disorder without epilepsy on pervasive developmental disorder scores, Childhood Autism Rating Scale scores, language disability, presence of regression, and epileptiform abnormalities. Epilepsy phenotype was also studied. Children with pervasive developmental disorder and epilepsy had higher pervasive developmental disorder scores (P = .001), higher Childhood Autism Rating Scale scores (P = .016), and lower social quotient (P = .09). More than 50% of children with pervasive developmental disorder and epilepsy and 12% of children having pervasive developmental disorder without epilepsy had epileptiform abnormalities in electroencephalography (EEG). Regression of milestones was significantly associated with epilepsy and epileptiform abnormalities. Children with pervasive developmental disorder and epilepsy might have a worse developmental trajectory requiring intensive management. A behavioral phenotype of autism may coexist often in children with epilepsy, EEG abnormalities, and regression. Seizures might be difficult to control in these children despite adequate compliance. Studies with larger sample size and longitudinal follow-up will provide better understanding.

The association between congenital anomalies and autism spectrum disorders in a Finnish national birth cohort

AIM

The first aim of this study was to evaluate the association between different subgroups of autism spectrum disorders (ASDs) (childhood autism, Asperger syndrome, and pervasive developmental disorder/pervasive developmental disorder - not otherwise specified [PDD/PDD-NOS]) and congenital anomalies. Second, we assessed the association among intellectually disabled children with ASDs in the subgroups of childhood autism and PDD/PDD-NOS.

METHOD

Nationwide population-based register data for children with a diagnosis of ASD (n=4449; 3548 males, 901 females) were collected during years 1987-2000 from the Finnish Hospital Discharge Register. Data on congenital anomalies were derived from the National Register of Congenital Malformations. Conditional logistic regression models were used as a statistical method. The association between ASD subgroups and congenital anomalies was stratified by the presence or absence of intellectual disability.

RESULTS

Congenital anomalies occurred more frequently in all subgroups of ASD than in comparison participants (adjusted odds ratio [OR] for major congenital anomalies 1.8, 95% confidence interval [CI] 1.5-2.2, p<0.001). The association between congenital anomalies and childhood autism (OR 2.4, 95% CI 1.6-3.6, p<0.001) and between congenital anomalies and PDD/PDD-NOS (OR 3.7, 95% CI 2.4-5.7, p<0.001) among children with an intellectual disability was strong but remained significant also without intellectual disability (childhood autism: OR 1.7, 95% CI 1.3-2.3, p<0.001; PDD/PDD-NOS: OR 2.3, 95% CI 1.9-2.8, p<0.001).

INTERPRETATION

The results suggest a significant association between ASDs and congenital anomalies regardless of the ASD subgroup. The association between childhood autism and PDD/PDD-NOS and congenital anomalies is stronger among children with intellectual disability is stronger than among those without intellectual disability. These results may have relevance in examining early risk factors in autism during fetal neurodevelopment.

Autism spectrum disorder in a term birth neonatal intensive care unit population

BACKGROUND

Nonspecific perinatal risk factors have been revealed to be associated with the development of autism spectrum disorder. However, term at-risk infants, as a distinct population, are underrepresented in the literature. This study examines the incidence and neonatal risk factors for autism spectrum disorder in term neonatal intensive care unit survivors.

METHODS

We performed a retrospective analysis from a single university-practice database of neonates admitted to the neonatal intensive care unit and followed by a single pediatric neurologist. Term infants (≥ 37 weeks), born between 1991 and 2011, with at least 2 years (or 1 year if found to be neurologically normal) of follow-up were included. Principle outcomes were autism spectrum disorder, cerebral palsy, global developmental delay, and epilepsy.

RESULTS

One hundred eighty infants were included from a database of 564 neonates. Twelve (6.6%) developed autism spectrum disorder, 53 (29.4%) cerebral palsy, 77 (42.7%) global developmental delay, and 47 (26.1%) epilepsy. Seventy-one (39.4%) developed no adverse outcomes. Nine patients with autism spectrum disorder (75%) were diagnosed with at least one other adverse outcome. No neonatal or perinatal variables were evident to be significantly associated with later autism spectrum disorder.

CONCLUSIONS

In term neonatal intensive care unit survivors, autism spectrum disorder occurs at a greater frequency than in the general population and often develops alongside comorbid conditions. This highlights the importance of screening term neonatal intensive care unit survivors for autism spectrum disorder, particularly when comorbidities are present.

Does epilepsy in multiplex autism pedigrees define a different subgroup in terms of clinical characteristics and genetic risk?

BACKGROUND

Autism spectrum disorders (ASD) and epilepsy frequently occur together. Prevalence rates are variable, and have been attributed to age, gender, comorbidity, subtype of pervasive developmental disorder (PDD) and risk factors. Recent studies have suggested disparate clinical and genetic settings depending on simplex or multiplex autism. The aim of this study was to assess: 1) the prevalence of epilepsy in multiplex autism and its association with genetic and non-genetic risk factors of major effect, intellectual disability and gender; and 2) whether autism and epilepsy cosegregate within multiplex autism families.

METHODS

We extracted from the Autism Genetic Resource Exchange (AGRE) database (n = 3,818 children from 1,264 families) all families with relevant medical data (n = 664 children from 290 families). The sample included 478 children with ASD and 186 siblings without ASD. We analyzed the following variables: seizures, genetic and non-genetic risk factors, gender, and cognitive functioning as assessed by Raven's Colored Progressive Matrices (RCPM) and Vineland Adaptive Behavior Scales (VABS).

RESULTS

The prevalence of epilepsy was 12.8% in cases with ASD and 2.2% in siblings without ASD (P <10-5). With each RCPM or VABS measure, the risk of epilepsy in multiplex autism was significantly associated with intellectual disability, but not with gender. Identified risk factors (genetic or non-genetic) of autism tended to be significantly associated with epilepsy (P = 0.052). When children with prematurity, pre- or perinatal insult, or cerebral palsy were excluded, a genetic risk factor was reported for 6/59 (10.2%) of children with epilepsy and 12/395 (3.0%) of children without epilepsy (P = 0.002). Finally, using a permutation test, there was significant evidence that the epilepsy phenotype co-segregated within families (P <10-4).

CONCLUSIONS

Epilepsy in multiplex autism may define a different subgroup in terms of clinical characteristics and genetic risk.

Prenatal, perinatal and neonatal risk factors for autism - study in Poland

The results of conducted research studies suggest that heredity and early fetal and neonatal development play a causal role in autism. The objective was to determine a relationship between pre-, peri-, and neonatal factors and autism. The relationship between genders and individual risk factors for autism was also examined. A case-control study was conducted among 288 children (96 cases with childhood or atypical autism and 192 controls individually matched to cases by the year of birth, sex, and general practitioners). Data on autism diagnosis and other medical conditions were acquired from physicians. All other information on potential autism risk factors were collected from mothers. Autism risk was significantly higher when mothers were taking medications (OR=2.72, 95%CI: 1.47-5.04) and smoked during pregnancy (OR=3.32, 95%CI: 1.12-9.82). It was also significantly associated with neonatal dyspnea (OR=3.20, 95%CI: 1.29-8.01) and congenital anomalies (OR=7.17, 95%CI: 2.23-23.1). In gender analysis only congenital anomalies were significantly associated with autism for girls but all of mentioned factors stayed independent risk factors for boys.

Pre-, peri- and neonatal risk factors for autism

OBJECTIVE

To identify pre-, peri- and neonatal risk factors for pervasive developmental disorders (PDD).

METHODS

We searched the Medline database through March 2011 for relevant case-control and population-based studies on pre-, peri- and neonatal hazards related to PDD, including autism. We identified 85 studies for this review. Data were extracted systematically and organized according to risk factors related to family history, pregnancy, gestational age, delivery, birth milestones and the neonate's condition at birth.

RESULTS

During the prenatal period, risk factors for PDD were advanced maternal or paternal ages, being firstborn vs. third or later, maternal prenatal medication use and mother's status as foreign born. During the perinatal and neonatal periods, the risk factors for PDD were preterm birth, breech presentation, planned cesarean section, low Apgar scores, hyperbilirubinemia, birth defect and a birthweight small for gestational age. The influence of maternal pre-eclampsia, diabetes, vomiting, infections and stress during pregnancy requires further study in order to determine risk for PDD.

DISCUSSION

Despite evidence for the association of some pre-, peri- and neonatal risk factors associated with PDD, it remains unclear whether these risks are causal or play a secondary role in shaping clinical expression in individuals with genetic vulnerability. A plausible hypothsesis is that improvements in obstetric and neonatal management have led to an increased rate of survivors with pre-existing brain damage. Given the variety of risk factors, we propose that future studies should investigate combinations of multiple factors, rather than focusing on a single factor.

Tricyclic antidepressants for autism spectrum disorders (ASD) in children and adolescents

BACKGROUND

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders, ranging in severity and characterised by early onset of delay and deviance in the development of social interaction, and verbal and nonverbal communication. ASD is associated with restricted and/or stereotyped interests or behaviours. Tricyclic antidepressants (TCAs) block noradrenaline and serotonin reuptake, increasing the availability of these neurotransmitters in the central nervous system. Via their impact on serotonin, TCAs have been used in the treatment of autistic symptoms and comorbidities in individuals with ASD.  

OBJECTIVES

To determine if treatment with tricyclic antidepressants:1) improves the core features of autism, including restricted social interaction, restricted communication, and stereotypical and repetitive behaviours; 2) improves non-core features such as challenging behaviours; 3) improves comorbid states, such as depression and anxiety; 4) causes adverse effects.

SEARCH METHODS

We ran the latest searches for this review on 23 May 2011. We searched: Cochrane Central Register of Controlled Trials (CENTRAL), 2011 Issue 2, MEDLINE (1948 to May Week 2, 2011), EMBASE (1980 to 2011 Week 2), PsycINFO (1887 to current), CINAHL (1937 to current). We also searched Dissertation Abstracts International via Dissertation Express, and the metaRegister of Controlled Trials.

SELECTION CRITERIA

Randomised controlled trials of any dose, duration and frequency of oral TCAs compared with placebo, in children and adolescents with a diagnosis of ASD, where at least one standardised outcome measure had been used.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected and appraised the studies for inclusion and risk of bias. All data were continuous.

MAIN RESULTS

Three studies met the inclusion criteria for this review. Two studies used clomipramine and one used tianeptine. All three trials were small, with between 12 and 32 participants. One of the clomipramine trials involved children and young adults, while the other two trials enrolled only children. Due to heterogeneity in study participant characteristics, the TCA medications investigated and the outcome measures used, we were not able to perform any meta-analysis.In only one of the three studies was there any indication that giving children tianeptine could be effective in the short term. In this study, parents and teachers reported that it reduced irritability, hyperactivity, inadequate eye contact and inappropriate speech, but clinician ratings found no significant impact on these symptoms. There were also significant adverse effects, including increased drowsiness and reduced activity levels in these individuals while being treated with tianeptine. The evidence of the impact of clomipramine in the two studies is contradictory. There was evidence of improvement in autistic symptoms, irritability and obsessive-compulsive disorder type symptoms, but conflicting evidence in relation to hyperactivity across the two studies, and no significant changes found with inappropriate speech. There were also adverse effects reported with the use of clomipramine. Although side effect ratings were not significantly different to placebo, there were significant dropout rates in the clomipramine arm of one study.

AUTHORS' CONCLUSIONS

Clinicians considering the use of TCAs need to be aware of the limited and conflicting evidence of effect and the side effect profile when discussing this treatment option with people who have ASD and their carers. Further research is required before TCAs can be recommended for treatment of individuals with ASD.

Have secular changes in perinatal risk factors contributed to the recent autism prevalence increase? Development and application of a mathematical assessment model

BACKGROUND

A 57% increase in the U.S. prevalence of autism spectrum disorders (ASD) for 8-year-old children born in 1994 versus 1998 was recently reported.

METHODS

To quantify the possible contributions of given risk/predictive factors on the recent ASD prevalence increase, we formulated a mathematical model based on the baseline risk factor prevalence (RFP), the proportionate change in RFP (cRFP), and the magnitude of the association between the risk factor and ASD [estimated relative risk (RR)]. We applied this model to several pregnancy-related factors (preterm, very preterm, low and very low birth weight, multiple birth, cesarean delivery, breech presentation, and assisted reproductive technology use). RFP and cRFP estimates for each factor were obtained from U.S. population-based surveillance datasets. Estimated RRs were obtained from a series of systematic literature reviews.

RESULTS

We estimate that each risk factor examined, alone or in various combinations, accounted for a very small proportion (<1%) of the ASD increase. Additionally, hypothetical scenarios indicate RFP, cRFP, and RR all need to be sizable for a risk factor to appreciably influence ASD prevalence.

CONCLUSIONS

Thus, although various pregnancy factors have been found to be associated with ASDs, the contribution of many of these factors to the recently observed ASD increase is likely minimal.

Perinatal and neonatal risk factors for autism: a comprehensive meta-analysis

BACKGROUND

The etiology of autism is unknown, although perinatal and neonatal exposures have been the focus of epidemiologic research for over 40 years.

OBJECTIVE

To provide the first review and meta-analysis of the association between perinatal and neonatal factors and autism risk.

METHODS

PubMed, Embase, and PsycInfo databases were searched for studies that examined the association between perinatal and neonatal factors and autism through March 2007. Forty studies were eligible for the meta-analysis. For each exposure, a summary effect estimate was calculated using a random-effects model. Heterogeneity in effect estimates across studies was examined, and, if found, a meta-regression was conducted to identify measured methodological factors that could explain between-study variability.

RESULTS

Over 60 perinatal and neonatal factors were examined. Factors associated with autism risk in the meta-analysis were abnormal presentation, umbilical-cord complications, fetal distress, birth injury or trauma, multiple birth, maternal hemorrhage, summer birth, low birth weight, small for gestational age, congenital malformation, low 5-minute Apgar score, feeding difficulties, meconium aspiration, neonatal anemia, ABO or Rh incompatibility, and hyperbilirubinemia. Factors not associated with autism risk included anesthesia, assisted vaginal delivery, postterm birth, high birth weight, and head circumference.

CONCLUSIONS

There is insufficient evidence to implicate any 1 perinatal or neonatal factor in autism etiology, although there is some evidence to suggest that exposure to a broad class of conditions reflecting general compromises to perinatal and neonatal health may increase the risk. Methodological variations were likely sources of heterogeneity of risk factor effects across studies.

Selective serotonin reuptake inhibitors (SSRIs) for autism spectrum disorders (ASD)

BACKGROUND

Autism spectrum disorders (ASD) are characterised by abnormalities in social interaction and communication skills, as well as stereotypic behaviours and restricted activities and interests. Selective serotonin reuptake inhibitors (SSRIs) are prescribed for the treatment of co-morbidity associated with ASD such as depression, anxiety and obsessive-compulsive behaviours.

OBJECTIVES

To determine if treatment with an SSRI: 1. improves the core features of autism (social interaction, communication and behavioural problems); 2. improves other non-core aspects of behaviour or function such as self-injurious behaviour; 3. improves the quality of life of children and their carers; 4. has short and long term effects on outcome; 5. causes harms.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2009, Issue 4), MEDLINE ( December 2009), EMBASE (December 2009), CINAHL (December 2009), PsycINFO (December 2009) and ERIC (December 2009), without language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of any dose of oral SSRI compared with placebo, in participants with autism spectrum disorders. Trials must have included at least one standardised outcome measure.

DATA COLLECTION AND ANALYSIS

Two authors independently selected and appraised studies for inclusion and risk of bias. All data were continuous. Meta-analysis, where possible, used a random-effects model.

MAIN RESULTS

Seven RCTs with a total of 271 participants were included. Four SSRIs were evaluated: fluoxetine (two studies), fluvoxamine (two studies), fenfluramine (two studies) and citalopram (one study). Five studies included only children and two studies included only adults. Varying inclusion criteria were used with regard to diagnostic criteria and intelligence of participants. Seventeen different outcome measures were reported. Although more than one study reported data for Clinical Global Impression (CGI) and obsessive-compulsive behaviour (OCB), different tool types or components of these outcomes were used in each study. As such, data were unsuitable for meta-analysis. One large, high quality study in children showed no evidence of positive effect of citalopram. Two small studies in adults showed positive outcomes for CGI and OCB; one study showed improvements in aggression and another in anxiety.

AUTHORS' CONCLUSIONS

There is no evidence of effect of SSRIs in children and emerging evidence of harm. There is limited evidence of the effectiveness of SSRIs in adults from small studies in which risk of bias is unclear.

Prenatal risk factors for autism: comprehensive meta-analysis

BACKGROUND

The aetiology of autism is unknown, although prenatal exposures have been the focus of epidemiological research for over 40 years.

AIMS

To provide the first quantitative review and meta-analysis of the association between maternal pregnancy complications and pregnancy-related factors and risk of autism.

METHOD

PubMed, Embase and PsycINFO databases were searched for epidemiological studies that examined the association between pregnancy-related factors and autism. Forty studies were eligible for inclusion in the meta-analysis. Summary effect estimates were calculated for factors examined in multiple studies.

RESULTS

Over 50 prenatal factors have been examined. The factors associated with autism risk in the meta-analysis were advanced parental age at birth, maternal prenatal medication use, bleeding, gestational diabetes, being first born v. third or later, and having a mother born abroad. The factors with the strongest evidence against a role in autism risk included previous fetal loss and maternal hypertension, proteinuria, pre-eclampsia and swelling.

CONCLUSIONS

There is insufficient evidence to implicate any one prenatal factor in autism aetiology, although there is some evidence to suggest that exposure to pregnancy complications may increase the risk.

Birth defects in children with autism spectrum disorders: a population-based, nested case-control study

The causes of autism spectrum disorders (ASDs) are unknown, although genetic and environmental influences have been implicated. Previous studies have suggested an association with birth defects, but most investigators have not addressed associations with specific diagnostic categories of ASD. In this study, the authors investigated the associations between birth defects and autism, Asperger syndrome, and pervasive developmental disorder not otherwise specified. Using Western Australian population-based linked data, the authors compared all children with ASD born in Western Australia during 1980-1995 (n = 465) with their siblings (n = 481) and population controls (n = 1,313) in a nested case-control study. The prevalence of birth defects was significantly higher in ASD cases than in population controls; this difference remained significant after adjustment for confounding factors. Odds ratios for birth defects were similar for autism (odds ratio (OR) = 2.0, 95% confidence interval (CI): 1.3, 3.0) and pervasive developmental disorder not otherwise specified (OR = 2.2, 95% CI: 1.1, 4.3) but not for Asperger syndrome (OR = 0.5, 95% CI: 0.1, 1.9). Birth defects in case siblings were not significantly different from those in cases and population controls. The association between birth defects and ASD may be due to underlying genetic and/or environmental factors common to both ASD and birth defects, or birth defects may predispose a child to ASD.

Tourette syndrome and comorbid pervasive developmental disorders

We examined the rates of comorbid pervasive developmental disorders in participants with Tourette syndrome. We used 7288 participants from the Tourette Syndrome International Database Consortium Registry. We found 334 (4.6%; 1 of every 22 participants) with Tourette syndrome had a comorbid pervasive developmental disorder. In participants with Tourette syndrome and comorbid pervasive developmental disorders, 98.8% had one or more comorbidities (pervasive developmental disorder was not counted) compared to 13.2% in the group of participants with Tourette syndrome only. Variables from logistic modeling that were significant predictors of Tourette syndrome and pervasive developmental disorders were: male gender; no family history of tics/Tourette syndrome; and an increased number of comorbidities (P < .001). We found rates of comorbid Tourette syndrome and pervasive developmental disorders to be increased by 13 times. Identification of differences between subgroups of patients with Tourette syndrome may increase understanding of syndromal susceptibility, severity, and outcome.

Epilepsy in autism is associated with intellectual disability and gender: evidence from a meta-analysis

BACKGROUND

The association between epilepsy and autism is consistently reported, with a wide range of prevalence rates. This may be attributed to the heterogeneity of the samples with respect to age, comorbidity, sex, and intellectual disability (ID). We aimed to compare the prevalence of epilepsy 1) among autistic patients with ID versus autistic patients without ID and 2) among male versus female autistic patients.

METHODS

We reviewed all data available from published reports (1963-2006) on autism and epilepsy and conducted a meta-analysis of 10 and 14 studies, respectively, to assess the relative risk (RR) of epilepsy in autism according to ID and gender. The pooled groups included 2112 (627 with IQ > or = 70, 1485 with IQ < 70) and 1530 (1191 male, 339 female) patients, respectively.

RESULTS

There was a strong discrepancy in relative risk (RR) according to IQ, with more autistic patients with ID having epilepsy (RR = .555; 95% confidence interval [CI]: .42-.73; p < .001). The pooled prevalence of epilepsy was 21.5% in autistic subjects with ID versus 8% in autistic subjects without ID. There was a strong discrepancy in RR according to sex, favoring comorbidity of epilepsy in autistic girls (RR = .549; 95% CI: .45-.66; p < .001). The male:female ratio of autism comorbid with epilepsy was close to 2:1 whereas the male:female ratio of autism without epilepsy was 3.5:1.

CONCLUSIONS

The results of this meta-analysis indicate that risk for epilepsy in autism is a function of ID severity and distinguishes autism associated with epilepsy as a subgroup of autism by its male-female ratio.