Matthew F. Pescosolido

Clinical Characteristics of Children with Autism Spectrum Disorder and Co-Occurring Epilepsy

Objectives To estimate the prevalence of epilepsy in children with Autism Spectrum Disorder (ASD) and to determine the demographic and clinical characteristics of children with ASD and epilepsy in a large patient population. Methods Cross-sectional study using four samples of children with ASD for a total of 5,815 participants with ASD. The prevalence of epilepsy was estimated from a population-based sample. Children with and without epilepsy were compared on demographic and clinical characteristics. Multivariate logistic regression was used to examine the association between demographic and clinical characteristics and epilepsy. Results The average prevalence of epilepsy in children with ASD 2–17 years was 12.5%; among children aged 13 years and older, 26% had epilepsy. Epilepsy was associated with older age, lower cognitive ability, poorer adaptive and language functioning, a history of developmental regression and more severe ASD symptoms. The association between epilepsy and the majority of these characteristics appears to be driven by the lower IQ of participants with epilepsy. In a multivariate regression model, only age and cognitive ability were independently associated with epilepsy. Children age 10 or older had 2.35 times the odds of being diagnosed with epilepsy (p<.001) and for a one standard deviation increase in IQ, the odds of having epilepsy decreased by 47% (p<.001). Conclusion This is among the largest studies to date of patients with ASD and co-occurring epilepsy. Based on a representative sample of children with ASD, the average prevalence of epilepsy is approximately 12% and reaches 26% by adolescence. Independent associations were found between epilepsy and older age and lower cognitive ability. Other risk factors, such as poor language and developmental regression, are not associated with epilepsy after controlling for IQ. These findings can help guide prognosis and alert clinicians to patients with ASD who are at increased risk for epilepsy.

Developmental meta-analysis of the functional neural correlates of autism spectrum disorders

OBJECTIVE There is a pressing need to elucidate the brain-behavior interactions underlying autism spectrum disorders (ASD) given the marked rise in ASD diagnosis over the past decade. Functional magnetic resonance imaging (fMRI) has begun to address this need, but few fMRI studies have evaluated age-related changes in ASD. Therefore, we conducted a developmental analysis of activation likelihood estimation (ALE) meta-analysis to compare child versus adult ASD fMRI studies. We hypothesized that children and adolescents with ASD (<18 years old) would rely less on prefrontal cortex structures than adults (≥18 years old). METHOD PubMed and PsycInfo literature searches were conducted to identify task-dependent fMRI studies of children or adults with ASD. Then recent GingerALE software improvements were leveraged to perform direct comparisons of child (n = 18) versus adult (n = 24) studies. RESULTS ALE meta-analyses of social tasks showed that children and adolescents with ASD versus adults had significantly greater hyperactivation in the left post-central gyrus, and greater hypoactivation in the right hippocampus and right superior temporal gyrus. ALE meta-analyses of nonsocial tasks showed that children with ASD versus adults had significantly greater hyperactivation in the right insula and left cingulate gyrus, and hypoactivation in the right middle frontal gyrus. CONCLUSION Our data suggest that the neural alterations associated with ASD are not static, occurring only in early childhood. Instead, children with ASD have altered neural activity compared to adults during both social and nonsocial tasks, especially in fronto-temporal structures. Longitudinal neuroimaging studies are required to examine these changes prospectively, as potential targets for brain-based treatments for ASD.

Genetic and phenotypic diversity of NHE6 mutations in Christianson syndrome

Recently, Christianson syndrome (CS) has been determined to be caused by mutations in the X‐linked Na+/H+ exchanger 6 (NHE6). We aimed to determine the diagnostic criteria and mutational spectrum for CS.

Expansion of the clinical phenotype associated with mutations in activity-dependent neuroprotective protein

Activity-dependent neuroprotective protein (ADNP) is a highly conserved transcription factor comprised of nine-zinc finger domains and a homeobox domain.1 ,2 It is highly expressed prenatally during critical stages of embryonic brain development.3 Knockout (KO) mouse embryos demonstrate severe neurodevelopmental morphological profiles.4 Although the ADNP KO is lethal, heterozygous embryos demonstrate typical embryogenesis yet display a neurodevelopmental delay phenotype including decreased neuronal survival.3 ,5 Exome sequencing in the Simons Simplex Collection autism dataset identified ADNP mutations as a putative autism gene candidate.6 ,7 Helsmoortel et al 8 recently reported 10 individuals with autism spectrum disorder (ASD) and mutations in exon 5 of the ADNP gene, nine of which were confirmed de novo. These patients also exhibited intellectual disability (ID) and dysmorphic features such as a prominent forehead. Mutations in the ADNP gene are estimated to be present in at least 0.17% of ASD cases. The current report further expands the ADNP phenotype to include abnormalities in the developing visual system (such as eye movement abnormalities and cortical visual impairment). We advise appropriate screening of eye movement and visual symptoms by clinicians in patients who have mutations in ADNP . The 6-year-old patient was the first child born to healthy non-consanguineous parents. Pregnancy was notable for placenta previa and early dilation and effacement of the cervix 3 weeks prior to delivery. The patient was born at 40 weeks via C-section secondary to failure to progress and maternal (i.e. maternal hypertension) hypertension weighing 6 pounds 14 ounces. She had a short stay in the neonatal intensive care unit (NICU) for breathe holding and feeding problems. She was also hospitalised at 6 weeks for an acute life-threatening event of multiple cyanotic episodes thought to be due to breath holding. Our patient has been diagnosed with hypotonia and mixed developmental …

An unbalanced translocation involving loss of 10q26.2 and gain of 11q25 in a pedigree with autism spectrum disorder and cerebellar juvenile pilocytic astrocytoma

We report on a pedigree with a pair of brothers each with minor anomalies, developmental delay, and autistic‐symptoms who share an unbalanced translocation (not detectable by karyotype). The unbalanced translocation involves a 7.1 Mb loss of the terminal portion of 10q, and a 4.2 Mb gain of 11q. One of the brothers also developed a cerebellar juvenile pilocytic astrocytoma. The father was found to be a balanced carrier and the couple had a previous miscarriage. We demonstrate that the breakpoint for the triplicated region from chromosome 11 is adjacent to two IgLON genes, namely Neurotrimin (NTM) and Opioid Binding Protein/Cell Adhesion Molecule‐like (OPCML). These genes are highly similar neural cell adhesion molecules that have been implicated in synaptogenesis and oncogenesis, respectively. The children also have a 10q deletion and are compared to other children with the 10q deletion syndrome which generally does not involve autism spectrum disorders (ASDs) or cancer. Together these data support a role for NTM and OPCML in developmental delay and potentially in cancer susceptibility.

A novel familial 11p15.4 microduplication associated with intellectual disability, dysmorphic features, and obesity with involvement of the ZNF214 gene

We evaluated a patient with mild intellectual disability, obesity, overgrowth, and dysmorphic features. Array comparative genomic hybridization (aCGH) analysis showed a single copy number increase of a BAC clone in the 11p15.4 region. Oligonucleotide aCGH refined the duplication to approximately 2.29 megabases (Mb) in size. Testing the parents revealed that the father, who had learning disabilities and overgrowth, also had the 11p15.4 duplication, and the mother had a normal microarray. In addition, the patients brother and grandmother all share clinical features with the proband and tested positive for the duplication. The duplicated region (Chr11:6,934,067‐9,220,605) encompasses 29 genes, including the ZNF214 gene, which has been postulated to play a role in Beckwith–Wiedemann syndrome [Alders et al., 2000 ]. This three‐generation pedigree outlines features of a novel microduplication syndrome.

Discovery of Rare Mutations in Autism: Elucidating Neurodevelopmental Mechanisms

Autism spectrum disorder (ASD) is a group of highly genetic neurodevelopmental disorders characterized by language, social, cognitive, and behavioral abnormalities. ASD is a complex disorder with a heterogeneous etiology. The genetic architecture of autism is such that a variety of different rare mutations have been discovered, including rare monogenic conditions that involve autistic symptoms. Also, de novo copy number variants and single nucleotide variants contribute to disease susceptibility. Finally, autosomal recessive loci are contributing to our understanding of inherited factors. We will review the progress that the field has made in the discovery of these rare genetic variants in autism. We argue that mutation discovery of this sort offers an important opportunity to identify neurodevelopmental mechanisms in disease. The hope is that these mechanisms will show some degree of convergence that may be amenable to treatment intervention.

Translational neuroscience in pediatric bipolar disorder.

Evaluation of: Pavuluri MN, Passarotti AM, Lu LH, Carbray JA, Sweeney JA. Double-blind randomized trial of risperidone versus divalproex in pediatric bipolar disorder: fMRI outcomes. Psychiatric Res. 193(1), 28–37 (2011). While controversial and often confounded with other forms of psychopathology, recent studies have shown that bipolar disorder (BD) is on the rise in children and adolescents. Research has made important strides in advancing our understanding of the phenomenology, neural underpinnings and treatment outcomes for BD youths. However, there is an increasing need to unite these domains to identify potential neural effects and predictors of treatment outcome. Pavuluri et al. have conducted such a study, evaluating the neural effects of divalproex or risperidone for pediatric BD. The future is likely to bring more of such studies, potentially resulting in a biomarker augmented approach to the diagnosis and treatment of pediatric BD.

Mixed neurodevelopmental and neurodegenerative pathology in Nhe6-null mouse model of Christianson syndrome

Abstract Christianson syndrome (CS) is an X-linked disorder resulting from loss-of-function mutations in SLC9A6, which encodes the endosomal Na+/H+ exchanger 6 (NHE6). Symptoms include early developmental delay, seizures, intellectual disability, nonverbal status, autistic features, postnatal microcephaly, and progressive ataxia. Neuronal development is impaired in CS, involving defects in neuronal arborization and synaptogenesis, likely underlying diminished brain growth postnatally. In addition to neurodevelopmental defects, some reports have supported neurodegenerative pathology in CS with age. The objective of this study was to determine the nature of progressive changes in the postnatal brain in Nhe6-null mice. We examined the trajectories of brain growth and atrophy in mutant mice from birth until very old age (2 yr). We report trajectories of volume changes in the mutant that likely reflect both brain undergrowth as well as tissue loss. Reductions in volume are first apparent at 2 mo, particularly in the cerebellum, which demonstrates progressive loss of Purkinje cells (PCs). We report PC loss in two distinct Nhe6-null mouse models. More widespread reductions in tissue volumes, namely, in the hippocampus, striatum, and cortex, become apparent after 2 mo, largely reflecting delays in growth with more limited tissue losses with aging. Also, we identify pronounced glial responses, particularly in major fiber tracts such as the corpus callosum, where the density of activated astrocytes and microglia are substantially increased. The prominence of the glial response in axonal tracts suggests a primary axonopathy. Importantly, therefore, our data support both neurodevelopmental and degenerative mechanisms in the pathobiology of CS.

Human neurons from Christianson syndrome iPSCs reveal allele-specific responses to rescue strategies

Human genetic disorders provide a powerful lens to understanding the human brain. Induced pluripotent stem cells (iPSC) represent an important, new resource for mechanistic studies and therapeutic development. Christianson syndrome (CS), an X-linked neurological disorder with attenuation of brain growth postnatally (postnatal microcephaly), is caused by mutations in SLC9A6, the gene encoding endosomal Na+/H+ exchanger 6 (NHE6). We developed CS iPSC lines from patients with a mutational spectrum, as well as robust biologically-related and isogenic controls. We demonstrate that mutations in CS lead to loss of protein function by a variety of mechanisms. Regardless of mutation, all patient-derived neurons demonstrate reduced neurite growth and arborization, likely underlying diminished postnatal brain growth in patients. Additionally, phenotype rescue strategies show allele-specific responses: a gene replacement strategy shows efficacy in nonsense mutations but not in a missense mutation, whereas application of exogenous trophic factors (BDNF or IGF-1) rescues arborization phenotypes across all mutations. Our data emphasize the important principle of personalized medicine whereby success of some therapeutic strategies may be more linked to patient genotype than others.