Distinctive facies,macrocephaly, and developmental delay are signs of a PTEN mutation in childhood

Background

Germline mutations of the PTEN gene are responsible for several PTEN hamartoma tumor syndromes. They are also implicated as a cause of macrocephaly and mild to severe developmental delay, regardless of the presence or absence of hamartomas in childhood. Nevertheless, because of limited information, the clinical features present during childhood in patients with a PTEN mutation are yet to be elucidated.

Phosphatase and tensin homolog (PTEN) gene mutations and autism: literature review and a case report of a patient with Cowden syndrome, autistic disorder, and epilepsy

Phosphatase and tensin homolog (PTEN) gene mutations are associated with a spectrum of clinical disorders characterized by skin lesions, macrocephaly, hamartomatous overgrowth of tissues, and an increased risk of cancers. Autism has rarely been described in association with these variable clinical features. At present, 24 patients with phosphatase and tensin homolog gene mutation, autism, macrocephaly, and some clinical findings described in phosphatase and tensin homolog syndromes have been reported in the literature. We describe a 14-year-old boy with autistic disorder, focal epilepsy, severe and progressive macrocephaly, and multiple papular skin lesions and palmoplantar punctate keratoses, characteristic of Cowden syndrome. The boy has a de novo phosphatase and tensin homolog gene mutation. Our patient is the first case described to present a typical Cowden syndrome and autism associated with epilepsy.     

Targeted treatments for cognitive and neurodevelopmental disorders in tuberous sclerosis complex

Until recently, the neuropsychiatric phenotype of tuberous sclerosis complex (TSC) was presumed to be caused by the structural brain abnormalities and/or seizures seen in the disorder. However, advances in the molecular biology of the disorder have shown that TSC is a mammalian target of rapamycin (mTOR) overactivation syndrome, and that direct molecular pathways exist between gene mutation and cognitive/neurodevelopmental phenotype. Molecularly-targeted treatments using mTOR inhibitors (such as rapamycin) are showing great promise for the physical and neurological phenotype of TSC. Pre-clinical and early-phase clinical studies of the cognitive and neurodevelopmental features of TSC suggest that some of the neuropsychiatric phenotypes might also be reversible, even in adults with the disorder. TSC, fragile X, neurofibromatosis type 1, and disorders associated with phosphatase and tensin homo (PTEN) mutations, all signal through the mTOR signaling pathway, with the TSC1-TSC2 protein complex as a molecular switchboard at its center. Together, these disorders represent as much as 14% of autism spectrum disorders (ASD). Therefore, we suggest that this signaling pathway is a key to the underlying pathophysiology of a significant subset of individuals with ASD. The study of molecularly targeted treatments in TSC and related disorders, therefore, may be of scientific and clinical value not only to those with TSC, but to a larger population that may have a neuropsychiatric phenotype attributable to mTOR overactivation or dysregulation.     

Implications for immunotherapy of tumor-mediated T-cell apoptosis associated with loss of the tumor suppressor PTEN in glioblastoma

The ability of glioma cells to escape the immune system remains a significant barrier to successful immunotherapy. Here we demonstrate that loss of the PTEN tumor suppressor gene, with associated activation of the PI3K/Akt/mTOR pathway, leads to a human glioma phenotype that induces autologous T-cell apoptosis upon contact. The PTEN status of pathologically confirmed glioblastoma specimens was defined, and primary cultures established after surgical resection of tumor from 26 patients. Autologous T-cells were isolated from these patients, and after T-cell activation was induced, these cells were co-cultured with matched autologous glioma cells, either alone, or after treatment with one of three inhibitors of the PI3K/Akt/mTOR pathway. When co-cultured with autologous T-cells, PTEN wild-type tumor cells induced apoptosis in a minimal number of activated T-cells (6–12% of T-cells), whereas tumors with PTEN loss induced much more profound levels of T-cell apoptosis (42–56% of T-cells). Prior treatment of PTEN-deficient tumor cells with specific inhibitors of the PI3K/Akt/mTOR pathway diminished T-cell apoptosis to levels seen after co-culture with wild-type PTEN tumor cells, suggesting that PTEN loss confers this immunoresistant phenotype through the PI3K/Akt/mTOR pathway. These results suggest that PTEN-deficient glioblastoma patients are suboptimal candidates for immunotherapy. In addition, our results raise the possibility of combining T-cell based immunotherapy protocols with clinical inhibitors of the PI3K/Akt/mTOR pathway.     

Tuberous Sclerosis: A New Frontier in Targeted Treatment of Autism

Tuberous sclerosis complex (TSC) is a genetic disorder with a high prevalence of autism spectrum disorder (ASD). Tremendous progress in understanding the pathogenesis of TSC has been made in recent years, along with initial trials of medical treatment aimed specifically at the underlying mechanism of the disorder. At the cellular level, loss of TSC1 or TSC2 results in upregulation of the mechanistic target of rapamycin (mTOR) pathway. At the circuitry level, TSC and mTOR play crucial roles in axonal, dendritic, and synaptic development and function. In this review, we discuss the molecular mechanism underlying TSC, and how this disease results in aberrant neural connectivity at multiple levels in the central nervous system, leading to ASD symptoms. We then review recent advances in mechanism-based treatments of TSC, and the promise that these treatments provide for future mechanism-based treatment of ASD. Because of these recent advances, TSC represents an ideal model for how to make progress in understanding and treating the mechanisms that underlie ASD in general.

Electronic supplementary material

The online version of this article (doi:10.1007/s13311-015-0359-5) contains supplementary material, which is available to authorized users.Key Words: mTOR, translation, white matter, cerebellum     

Neurodevelopmental disorders in children with macrocephaly: A prevalence study and PTEN gene analysis

Purpose

To clarify the relationship between macrocephaly and neurodevelopmental disorders, as well as identify the prevalence of PTEN mutations in autism spectrum disorders with macrocephaly in Japan.

Temporal lobe connects regression and macrocephaly to autism spectrum disorders

Interictal electroencephalogram (EEG) abnormalities are frequently associated with autism spectrum disorders (ASD), although their relationship with the clinical features of ASD, particularly the regressive onset, remains controversial. The aim of this study was to investigate whether the characteristics of interictal EEG abnormalities might help to distinguish and predict definite phenotypes within the heterogeneity of ASD. We reviewed the awake and sleep interictal EEGs of 220 individuals with idiopathic ASD, either with or without a history of seizures. EEG findings were analyzed with respect to a set of clinical variables to explore significant associations. A brain morphometry study was also carried out on a subgroup of patients. EEG abnormalities were seen in 154/220 individuals (70 %) and were mostly focal (p < 0.01) with an anterior localization (p < 0.001). They were detected more frequently during sleep (p < 0.01), and were associated with a regressive onset of ASD (p < 0.05), particularly in individuals with focal temporal localization (p < 0.05). This association was also stronger in regressive patients with concurrent macrocephaly, together with a relative volumetric reduction of the right temporal cortex (p < 0.05). Indeed, concurrence of temporal EEG abnormalities, regression and macrocephaly might possibly define a distinct endophenotype of ASD. EEG-based endophenotypes could be useful to untangle the complexity of ASD, helping to establish anatomic or pathophysiologic subtypes of the disorder.     

<Emphasis Type="Italic">PTEN</Emphasis> methylation and expression in glioblastomas

The tumor suppressor gene PTEN on chromosome 10q23.3 regulates the Akt signaling pathway and modulates cell growth and apoptosis. The PTEN gene is mutated in 20–40% of glioblastomas. In this study, we assessed whether loss of PTEN expression is also caused epigenetically. Methylation-specific PCR revealed that CpG islands of the PTEN promoter were methylated in 27 of 77 (35%) glioblastomas and in 4 of 11 (36%) glioblastoma cell lines. Only two glioblastomas showed loss of PTEN immunoreactivity in the entire biopsy; both had a missense PTEN mutation and LOH at the PTEN locus, but lacked PTEN methylation. In biopsy specimens with focal loss of PTEN expression, DNA samples extracted from microdissected foci showed PTEN methylation only in areas with loss of PTEN expression. These results suggest that PTEN methylation occurs frequently in glioblastomas and may be associated with focal loss of PTEN expression. However, the correlation between PTEN methylation, PTEN mutations, LOH at the PTEN locus, and loss of PTEN protein expression was inconsistent. Possible reasons for discrepancies between gene status and protein expression include differences in the biological effect of specific PTEN mutations and the possibility that the processed PTEN pseudogene on 9p21 is expressed in glioblastomas and co-reacts with the PTEN antibody.     

Behavioral and Neuroanatomical Phenotypes in Mouse Models of Autism

In order to understand the consequences of the mutation on behavioral and biological phenotypes relevant to autism, mutations in many of the risk genes for autism spectrum disorder have been experimentally generated in mice. Here, we summarize behavioral outcomes and neuroanatomical abnormalities, with a focus on high-resolution magnetic resonance imaging of postmortem mouse brains. Results are described from multiple mouse models of autism spectrum disorder and comorbid syndromes, including the 15q11-13, 16p11.2, 22q11.2, Cntnap2, Engrailed2, Fragile X, Integrinβ3, MET, Neurexin1a, Neuroligin3, Reelin, Rett, Shank3, Slc6a4, tuberous sclerosis, and Williams syndrome models, and inbred strains with strong autism-relevant behavioral phenotypes, including BTBR and BALB. Concomitant behavioral and neuroanatomical abnormalities can strengthen the interpretation of results from a mouse model, and may elevate the usefulness of the model system for therapeutic discovery.

Electronic supplementary material

The online version of this article (doi:10.1007/s13311-015-0360-z) contains supplementary material, which is available to authorized users.     

Neuroglobin Protects Rats from Sepsis-Associated Encephalopathy via a PI3K/Akt/Bax-Dependent Mechanism

The pathogenesis of autism spectrum disorders (ASD) is not completely understood, but there is evidence of associations with altered immune responses. The aim of this study was to determine the serum levels of various cytokines in children with ASD and in healthy controls, in order to determine their role in ASD and its diagnostic subgroups. Sixty-five ASD patients were enrolled from an epidemiological survey in Norway, of which 30 were diagnosed with childhood autism, 16 with Asperger syndrome, 12 with atypical autism, 1 with Rett syndrome, and 6 with another ASD diagnosis. The serum levels of 12 cytokines were measured in all of the patients and in 30 healthy children. The cytokine levels did not differ significantly between the ASD group and the healthy controls. However, the interleukin-8 (IL-8) level was significantly higher (6.82 vs 4.58 pg/ml, p?=?0.017) while that of IL-10 was significantly lower (2.24 vs 6.49 pg/ml, p?=?0.009) in patients with childhood autism than in controls. Furthermore, the IL-8 level was significantly higher in childhood autism than in Asperger syndrome (6.82 vs 4.05 pg/ml, p?=?0.013). Our study shows that the cytokine profile of children diagnosed with ASD, regardless of the subdiagnosis, does not differ from healthy controls. However, differentiation into different diagnostic subgroups reveals significantly different levels of IL-8 and IL-10. This indicates that different mechanisms may underlie the different ASD subdiagnoses. Future research into the pathophysiological mechanisms of ASD should pay more attention to the different subdiagnoses of ASD.     

Overlapping Molecular Pathways Leading to Autism Spectrum Disorders,Fragile X Syndrome,and Targeted Treatments

Autism spectrum disorders (ASD) are subdivided into idiopathic (unknown) etiology and secondary, based on known etiology. There are hundreds of causes of ASD and most of them are genetic in origin or related to the interplay of genetic etiology and environmental toxicology. Approximately 30 to 50% of the etiologies can be identified when using a combination of available genetic testing. Many of these gene mutations are either core components of the Wnt signaling pathway or their modulators. The full mutation of the fragile X mental retardation 1 (FMR1) gene leads to fragile X syndrome (FXS), the most common cause of monogenic origin of ASD, accounting for ~ 2% of the cases. There is an overlap of molecular mechanisms in those with idiopathic ASD and those with FXS, an interaction between various signaling pathways is suggested during the development of the autistic brain. This review summarizes the cross talk between neurobiological pathways found in ASD and FXS. These signaling pathways are currently under evaluation to target specific treatments in search of the reversal of the molecular abnormalities found in both idiopathic ASD and FXS.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13311-020-00968-6.Key Words: Autism spectrum disorders, fragile X syndrome, targeted treatments, Wnt, retinoic acid, mTOR, ERK/MAPK, signaling cross talk, endocannabinoid system, neurodevelopmental disorders     

Pten deletion in adult hippocampal neural stem/progenitor cells causes cellular abnormalities and alters neurogenesis

Adult neurogenesis persists throughout life in restricted brain regions in mammals and is affected by various physiological and pathological conditions. The tumor suppressor gene Pten is involved in adult neurogenesis and is mutated in a subset of autism patients with macrocephaly; however, the link between the role of PTEN in adult neurogenesis and the etiology of autism has not been studied before. Moreover, the role of hippocampus, one of the brain regions where adult neurogenesis occurs, in development of autism is not clear. Here, we show that ablating Pten in adult neural stem cells in the subgranular zone of hippocampal dentate gyrus results in higher proliferation rate and accelerated differentiation of the stem/progenitor cells, leading to depletion of the neural stem cell pool and increased differentiation toward the astrocytic lineage at later stages. Pten-deleted stem/progenitor cells develop into hypertrophied neurons with abnormal polarity. Additionally, Pten mutant mice have macrocephaly and exhibit impairment in social interactions and seizure activity. Our data reveal a novel function for PTEN in adult hippocampal neurogenesis and indicate a role in the pathogenesis of abnormal social behaviors.     

Neuropsychological and neurophysiological features of WAGR syndrome: Detailed comprehensive evaluation of a patient with severe intellectual disability and autism spectrum disorder

BackgroundWilms’ tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome is a contiguous gene deletion syndrome caused by a de novo deletion including the 11p13 region. Although autism spectrum disorder (ASD) is frequently observed in patients with WAGR syndrome, few reports have comprehensively described its characteristics. We herein present the detailed neuropsychological and neurophysiological findings of a patient with WAGR syndrome complicated with severe psychomotor developmental delay and ASD.Case presentationThe patient is presently a 6-year-old boy. Microarray analysis revealed a 7.1 Mb loss at 11p14.3-p13 and a 9.3 Mb loss at 11p13-p12, which encompassed the PAX6, WT1, and PRRG4 genes. His behavioral features were characteristic even among the ASD population: severe hypoesthesia to touch, pain, and temperature in addition to remarkable sensory seeking posing a high risk of serious accident. Sensory Profile analysis objectively identified a strong preference for sensory stimulation. Furthermore, his somatosensory evoked potential (SSEP) showed a mild delay in central conduction time, suggesting partial brain stem dysfunction-induced hypoalgesia.DiscussionThis first attempt to characterize sensory dysfunction using Sensory Profile and SSEP in WAGR syndrome may contribute to understanding its neuropsychological features and improve the quality of rehabilitation and socioeducational support in affected children.     

Hemimegalencephaly with Bannayan‐Riley‐Ruvalcaba syndrome

Hemimegalencephaly is known to occur in Proteus syndrome, but has not been reported, to our knowledge, in the other PTEN mutation‐related syndrome of Bannayan‐Riley‐Ruvalcaba. Here, we report a patient with Bannayan‐Riley‐Ruvalcaba syndrome who also had hemimegalencephaly and in whom the hemimegalencephaly was evident well before presentation of the characteristic manifestations of Bannayan‐Riley‐Ruvalcaba syndrome. An 11‐year‐old boy developed drug‐resistant focal seizures on the fifth day of life. MRI revealed left hemimegalencephaly. He later showed macrocephaly, developmental delay, athetotic quadriplegic cerebral palsy, and neuromuscular scoliosis. Freckling of the penis, which is characteristic of Bannayan‐Riley‐Ruvalcaba syndrome, was not present at birth but was observed at 9 years of age. Gene analysis revealed a c.510 T>G PTEN mutation. This patient and his other affected family members, his father and two siblings, were started on the tumour screening procedures recommended for patients with PTEN mutations. This case highlights the importance of early screening for PTEN mutations in cases of hemimegalencephaly not otherwise explained by another disorder, even in the absence of signs of Proteus syndrome or the full manifestations of Bannayan‐Riley Ruvalcaba syndrome.     

Neurodevelopmental Disorders Affecting Sociability: Recent Research Advances and Future Directions in Autism Spectrum Disorder and Williams Syndrome

Purpose of Review

In this review, we summarize current knowledge and hypotheses on the nature of social abnormalities in autism spectrum disorder (ASD) and Williams syndrome (WS).

Recent Findings

Social phenotypes in ASD and WS appear to reflect analogous disruptions in social cognition, and distinct patterns of social motivation, which appears to be reduced in ASD and enhanced in WS. These abnormalities likely originate from heterogeneous vulnerabilities that disrupt the interplay between domain-general and social domain-specific cognitive and motivational processes during early development. Causal pathways remain unclear.

Summary

Advances and research gaps in our understanding of the social phenotypes in ASD and WS highlight the importance of (1) parsing the construct of sociability, (2) adopting a developmental perspective, (3) including samples that are representative of the spectrum of severity within ASD and WS in neuroscientific research, and (4) adopting transdiagnostic treatment approaches to target shared areas of impairment across diagnostic boundaries.

     

Theory of mind in autism spectrum disorder: Does DSM classification predict development?

It is unclear how theory of mind (ToM; understanding mental states and their influence on behaviour) develops in autism spectrum disorders (ASD). At least two possibilities exist: development is delayed or developmental patterns deviate from normal. We used a cross-sectional design to examine ToM skills in 4–16 year-old children. First, participants were classified in terms of the DSM-IV categories low-functioning autism (n = 21), high-functioning autism (n = 24), Asperger's syndrome (n = 21), and pervasive developmental disorder not otherwise specified (PDD-NOS; n = 20). The high-functioning autism, Asperger's syndrome and PDD-NOS groups displayed delayed ToM onset compared to a typically developing group (n = 30), but normal ToM developmental rates and sequences; supporting delayed development. ToM in low-functioning ASD fit the deviant development model: Age did not predict ToM. A second ToM model using DSM-5 ASD and verbal IQ supported ToM development differences: Greater verbal ability was associated with increased ToM in ASD but not in typical development. As a single explanation for ToM development in ASD is insufficient, it is imperative to report specifiers such as intellectual functioning when using DSM-5 classification. DSM-IV classification contributed little to the prediction of ToM development beyond the influence of intellectual functioning.     

Valproic acid exposure sequentially activates Wnt and mTOR pathways in rats

BackgroundAutism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social interaction, limited verbal communication and repetitive behaviors. Recent studies have demonstrated that Wnt signaling and mTOR signaling play important roles in the pathogenesis of ASD. However, the relationship of these two signaling pathways in ASD remains unclear.ResultsWe assessed this question using the valproic acid (VPA) rat model of autism. Our results demonstrated that VPA exposure activated mTOR signaling and suppressed autophagy in the prefrontal cortex, hippocampus and cerebellum of autistic model rats, characterized by enhanced phospho-mTOR and phospho-S6 and decreased Beclin1, Atg5, Atg10, LC3-II and autophagosome formation. Rapamycin treatment suppressed the effect of VPA on mTOR signaling and ameliorated the autistic-like behaviors of rats in our autism model. The administration of VPA also activated Wnt signaling through up-regulating beta-catenin and phospho-GSK3beta. Suppression of the Wnt pathway by sulindac relieved autistic-like behaviors and attenuated VPA-induced mTOR signaling activation in autistic model rats.ConclusionsOur results demonstrate that VPA exposure sequentially activates Wnt signaling and mTOR signaling in rats. Suppression of the Wnt signaling pathway relieves autistic-like behaviors partially by deactivating the mTOR signaling pathway in VPA-exposed rats.     

Phelan–McDermid Syndrome and SHANK3: Implications for Treatment

Phelan–McDermid syndrome (PMS), also called 22q13.3 deletion syndrome, is a neurodevelopmental disorder characterized by global developmental delay, intellectual disability, severe speech delays, poor motor tone and function, and autism spectrum disorder (ASD). Although the overall prevalence of PMS is unknown, there have been at least 1200 cases reported worldwide, according to the Phelan–McDermid Syndrome Foundation. PMS is now considered to be a relatively common cause of ASD and intellectual disability, accounting for between 0.5 % and 2.0 % of cases. The cause of PMS has been isolated to loss of function of one copy of SHANK3, which codes for a master scaffolding protein found in the postsynaptic density of excitatory synapses. Reduced expression of SH3 and multiple ankyrin repeat domains 3 (SHANK3) leads to reduced numbers of dendrites, and impaired synaptic transmission and plasticity. Recent mouse and human neuronal models of PMS have led to important opportunities to develop novel therapeutics, and at least 2 clinical trials are underway, one in the USA, and one in the Netherlands. The SHANK3 pathway may also be relevant to other forms of ASD, and many of the single-gene causes of ASD identified to date appear to converge on several common molecular pathways that underlie synaptic neurotransmission. As a result, treatments developed for PMS may also affect other forms of ASD.

Electronic supplementary material

The online version of this article (doi:10.1007/s13311-015-0352-z) contains supplementary material, which is available to authorized users.     

ASH1L mutation caused seizures and intellectual disability in twin sisters

ASH1L mutations have been identified with variable phenotypes, including intellectual disability, autism spectrum disorder (ASD), and multiple congenital anomalies (MCA). However, the mechanisms underlying this phenotypic variation remain unknown. Here, we present twin sisters exhibiting mild intellectual disability and seizures. Whole-exome sequencing of the family revealed a novel de novo heterozygous sequence variant, NM_018489.2: c.2678dup (p.Lys894*) in exon 3 of ASH1L which was estimated to be pathogenic. Furthermore, we reviewed previously reported ASH1L mutations in order to evaluate genotype-phenotype correlations for ASH1L variants. We found that patients with missense mutations in ASH1L appeared to present with more severe phenotypes and a higher likelihood of ASD than those with truncating mutations. The relationship between phenotype and genotype reported across several patients may help to explain the mechanisms underlying the phenotypic variation commonly observed between ASH1L mutations.