De novo variants in PAK1 lead to intellectual disability with macrocephaly and seizures.

Using trio exome sequencing, we identified de novo heterozygous missense variants in PAK1 in four unrelated individuals with intellectual disability, macrocephaly and seizures. PAK1 encodes the p21-activated kinase, a major driver of neuronal development in humans and other organisms. In normal neurons, PAK1 dimers reside in a trans-inhibited conformation, where each autoinhibitory domain covers the kinase domain of the other monomer. Upon GTPase binding via CDC42 or RAC1, the PAK1 dimers dissociate and become activated. All identified variants are located within or close to the autoinhibitory switch domain that is necessary for trans-inhibition of resting PAK1 dimers. Protein modelling supports a model of reduced ability of regular autoinhibition, suggesting a gain of function mechanism for the identified missense variants. Alleviated dissociation into monomers, autophosphorylation and activation of PAK1 influences the actin dynamics of neurite outgrowth. Based on our clinical and genetic data, as well as the role of PAK1 in brain development, we suggest that gain of function pathogenic de novo missense variants in PAK1 lead to moderate-to-severe intellectual disability, macrocephaly caused by the presence of megalencephaly and ventriculomegaly, (febrile) seizures and autism-like behaviour.

Psychological and cognitive evaluation of autism in a patient with MOMO syndrome: a case report and literature review. / Evaluación psicológica y cognitiva de autismo en un paciente con síndrome de MOMO: reporte de caso y revisión de la literatura.

MOMO is an acronym for macrosomia, obesity, macrocephaly and ocular abnormalities. The syndrome was first described in 1993, with a total of nine patients published thus far. All the cases presented intellectual disability and in one case autism was described. We present a new case of a patient with MOMO syndrome, who consulted for hallucinatory phenomena. He completed a neuropsychological, clinical and cognitive evaluation, showing a borderline intelligence quotient and fulfilled the criteria for autism spectrum disorder. This is the first neurocognitive evaluation of a patient with MOMO, supporting the use of standardized scales in order to assess the autism and other psychiatric comorbidities in patients with genetics syndromes.

MOMO es un acrónimo para los términos macrosomía, obesidad, macrocefalia y anomalías oculares. El síndrome fue descrito por primera vez en 1993, con un total de nueve pacientes publicados a la fecha. Todos los casos reportaron discapacidad intelectual y en un caso se describió a un paciente con autismo. Presentamos un nuevo caso de paciente con síndrome de MOMO que consultó por fenómenos alucinatorios. Se completó una evaluación neuropsicológica, clínica y cognitiva, en donde se demostró un cociente intelectual limítrofe y se corroboraron los criterios para trastorno del espectro autista. Ésta es la primera evaluación neurocognitiva de un paciente con MOMO, la que apoya el uso de escalas estandarizadas a fin de evaluar el autismo y otras comorbilidades psiquiátricas en pacientes con síndromes genéticos.

Heterozygosity for Nuclear Factor One X in mice models features of Malan syndrome.

BACKGROUND: Nuclear Factor One X (NFIX) haploinsufficiency in humans results in Malan syndrome, a disorder characterized by overgrowth, macrocephaly and intellectual disability. Although clinical assessments have determined the underlying symptomology of Malan syndrome, the fundamental mechanisms contributing to the enlarged head circumference and intellectual disability in these patients remains undefined. METHODS: Here, we used Nfix heterozygous mice as a model to investigate these aspects of Malan syndrome. Volumetric magnetic resonance imaging (MRI) was used to calculate the volumes of 20 brain sub regions. Diffusion tensor MRI was used to perform tractography-based analyses of the corpus callosum, hippocampal commissure, and anterior commissure, as well as structural connectome mapping of the whole brain. Immunohistochemistry examined the neocortical cellular populations. Two behavioral assays were performed, including the active place avoidance task to assess spatial navigation and learning and memory function, and the 3-chambered sociability task to examine social behaviour. FINDINGS: Adult Nfix+/- mice exhibit significantly increased brain volume (megalencephaly) compared to wildtypes, with the cerebral cortex showing the highest increase. Moreover, all three forebrain commissures, in particular the anterior commissure, revealed significantly reduced fractional anisotropy, axial and radial diffusivity, and tract density intensity. Structural connectome analyses revealed aberrant connectivity between many crucial brain regions. Finally, Nfix+/- mice exhibit behavioral deficits that model intellectual disability. INTERPRETATION: Collectively, these data provide a significant conceptual advance in our understanding of Malan syndrome by suggesting that megalencephaly underlies the enlarged head size of these patients, and that disrupted cortical connectivity may contribute to the intellectual disability these patients exhibit. FUND: Australian Research Council (ARC) Discovery Project Grants, ARC Fellowship, NYSTEM and Australian Postgraduate Fellowships.

Evaluación psicológica y cognitiva de autismo en un paciente con síndrome de MOMO: reporte de caso y revisión de la literatura / Psychological and cognitive evaluation of autism in a patient with MOMO syndrome: a case report and literature review

MOMO es un acrónimo para los términos macrosomía, obesidad, macrocefalia y anomalías oculares. El síndrome fue descrito por primera vez en 1993, con un total de nueve pacientes publicados a la fecha. Todos los casos reportaron discapacidad intelectual y en un caso se describió a un paciente con autismo. Presentamos un nuevo caso de paciente con síndrome de MOMO que consultó por fenómenos alucinatorios. Se completó una evaluación neuropsicológica, clínica y cognitiva, en donde se demostró un cociente intelectual limítrofe y se corroboraron los criterios para trastorno del espectro autista. Ésta es la primera evaluación neurocognitiva de un paciente con MOMO, la que apoya el uso de escalas estandarizadas a fin de evaluar el autismo y otras comorbilidades psiquiátricas en pacientes con síndromes genéticos.

MOMO is an acronym for macrosomia, obesity, macrocephaly and ocular abnormalities. The syndrome was first described in 1993, with a total of nine patients published thus far. All the cases presented intellectual disability and in one case autism was described. We present a new case of a patient with MOMO syndrome, who consulted for hallucinatory phenomena. He completed a neuropsychological, clinical and cognitive evaluation, showing a borderline intelligence quotient and fulfilled the criteria for autism spectrum disorder. This is the first neurocognitive evaluation of a patient with MOMO, supporting the use of standardized scales in order to assess the autism and other psychiatric comorbidities in patients with genetics syndromes.

A clinical review on megalencephaly: A large brain as a possible sign of cerebral impairment.

Megalencephaly and macrocephaly present with a head circumference measurement 2 standard deviations above the age-related mean. However, even if pathologic events resulting in both megalencephaly and macrocephaly may coexist, a distinction between these two entities is appropriate, as they represent clinical expression of different disorders with a different approach in clinical work-up, overall prognosis, and treatment. Megalencephaly defines an increased growth of cerebral structures related to dysfunctional anomalies during the various steps of brain development in the neuronal proliferation and/or migration phases or as a consequence of postnatal abnormal events. The disorders associated with megalencephaly are classically defined into 3 groups: idiopathic or benign, metabolic, and anatomic. In this article, we seek to underline the clinical aspect of megalencephaly, emphasizing the main disorders that manifest with this anomaly in an attempt to properly categorize these disorders within the megalencephaly group.

Brief Report: Macrocephaly Phenotype and Psychiatric Comorbidity in a Clinical Sample of Mexican Children and Adolescents with Autism Spectrum Disorders.

Autism spectrum disorders (ASD) may present with macrocephaly. Few studies have analyzed the association with psychiatric comorbidity. Participants were 94 children with any ASD with an age range from 2 to 16 years (Mdn 6 years), 82% were boys. It was found that 20% of the sample had macrocephaly and 1% microcephaly. There was no association between the presence of macrocephaly and subtype of ASD. The most associated comorbidity was attention-deficit/hyperactivity disorder (ADHD) 54.2%, followed by specific phobia 34%, dysthimia 29.7%, oppositional defiant disorder 13.83% motor tics 11.7%, separation anxiety 9.5% and Gilles de la Tourette 8.5%. In conclusion, macrocephaly and psychiatric comorbidity in this clinical sample of children with ASD is similar to the international literature results.

In pursuit of neurophenotypes: The consequences of having autism and a big brain.

A consensus has emerged that despite common core features, autism spectrum disorder (ASD) has multiple etiologies and various genetic and biological characteristics. The fact that there are likely to be subtypes of ASD has complicated attempts to develop effective therapies. The UC Davis MIND Institute Autism Phenome Project is a longitudinal, multidisciplinary analysis of children with autism and age-matched typically developing controls; nearly 400 families are participating in this study. The overarching goal is to gather sufficient biological, medical, and behavioral data to allow definition of clinically meaningful subtypes of ASD. One reasonable hypothesis is that different subtypes of autism will demonstrate different patterns of altered brain organization or development i.e., different neurophenotypes. In this Commentary, we discuss one neurophenotype that is defined by megalencephaly, or having brain size that is large and disproportionate to body size. We have found that 15% of the boys with autism demonstrate this neurophenotype, though it is far less common in girls. We review behavioral and medical characteristics of the large-brained group of boys with autism in comparison to those with typically sized brains. While brain size in typically developing individuals is positively correlated with cognitive function, the children with autism and larger brains have more severe disabilities and poorer prognosis. This research indicates that phenotyping in autism, like genotyping, requires a very substantial cohort of subjects. Moreover, since brain and behavior relationships may emerge at different times during development, this effort highlights the need for longitudinal analyses to carry out meaningful phenotyping. Autism Res 2017, 10: 711-722. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Megalencephaly-capillary malformation polymicrogyria: A review and complex pediatric case report.

Megalencephaly-Capillary Malformation Polymicrogyria (M-CAP) is a rare genetic disorder characterized by a spectrum of anomalies including macrocephaly and neurovascular malformations. Although developmental delays have been identified, research is devoid of neuropsychological data. This case report presents the neuropsychological profile of a 7-year-old, identified with M-CAP. Neuropsychological evaluation was completed subsequent to medical diagnosis. Reports from both parents and teachers included cognitive regression; specifically in the recall of learned material, reading, and information sequencing. Direct testing revealed a WISC-IV GAI at <1st percentile, a diverse range of scores across the battery, and a splinter skill strength of average to above on visual memory tests. Performance included below grade level reading and writing, reduced adaptive functioning, and reported executive dysfunction. Her strong visual memory skills were recommended as a medium to enhance learning. Neurocognitive deficits revealed diverse, multisystem and multifocal impairments. The neuropsychological evaluation also showed significant decline from the previous evaluation and prompted a neurologic consult and corrective surgical procedure.

Síndromes de sobrecrecimiento y desarrollo de tumores embrionarios: revisión de nuestra casuística en los últimos 5 años / Overgrowth syndromes and development of embryonic tumours: A review of cases in the last 5 years

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Prenatal head growth and child neuropsychological development at age 14 months.

OBJECTIVE: We sought to assess the association between prenatal head growth and child neuropsychological development in the general population. STUDY DESIGN: We evaluated 2104 children at the age of 14 months from a population-based birth cohort in Spain. Head circumference (HC) was measured by ultrasound examinations at weeks 12, 20, and 34 of gestation and by a nurse at birth. Head growth was assessed using conditional SD scores between weeks 12-20 and 20-34. Trained psychologists assessed neuropsychological functioning using the Bayley Scales of Infant Development. Head size measurements at birth were transformed into a 3-category variable: microcephalic (<10th percentile), normocephalic (≥10th and <90th percentile), and macrocephalic (≥90th percentile) based on the cohort distribution. P values<.05 were considered statistically significant. RESULTS: No overall associations were observed between HC or head growth and mental and psychomotor scores. In particular, no associations were found between HC at birth and mental scores (coefficient, 0.04; 95% confidence interval, -0.02 to 0.09) and between interval head growth (20-34 weeks) and mental scores (0.31; 95% confidence interval, -0.36 to 0.99). Upon stratification by microcephalic, normocephalic, or macrocephalic head size, results were imprecise, although there were some significant associations in the microcephalic and macrocephalic groups. Adjustment by various child and maternal cofactors did not affect results. The minimum sample size required for present study was 883 patients (ß=2, α=0.05, power=0.80). CONCLUSION: Overall prenatal and perinatal HC was not associated with 14-month-old neuropsychological development. Findings suggest HC growth during uterine life among healthy infants may not be an important marker of early-life neurodevelopment but may be marginally useful with specific populations.

Reduction cranioplasty for macrocephaly caused by giant occipital cystic lesion.

Reduction cranioplasty for macrocephaly improves patients' quality of life both functionally and aesthetically. However, it is indicated for only a small number of patients because of the risks of complications. Thus, it is rarely performed, and not many reports have been published. In Dandy-Walker syndrome, there is often a posterior fossa cyst continuous with the fourth ventricle. We report here a case of scaphocephalic macrocephaly because of such a cystic lesion. The patient underwent a single-stage surgery with plication of the cyst wall and posterior reduction cranioplasty. This procedure achieved good results.

Early generalized overgrowth in boys with autism.

CONTEXT: Multiple studies have reported an overgrowth in head circumference (HC) in the first year of life in autism. However, it is unclear whether this phenomenon is independent of overall body growth and whether it is associated with specific social or cognitive features. OBJECTIVES: To examine the trajectory of early HC growth in autism compared with control groups; to assess whether HC growth in autism is independent of height and weight growth during infancy; and to examine HC growth from birth to 24 months in relationship to social, verbal, cognitive, and adaptive functioning levels. DESIGN: Retrospective study. SETTING: A specialized university-based clinic. PARTICIPANTS: Boys diagnosed as having autistic disorder (n = 64), pervasive developmental disorder-not otherwise specified (n = 34), global developmental delay (n = 13), and other developmental problems (n = 18) and typically developing boys (n = 55). MAIN OUTCOME MEASURES: Age-related changes in HC, height, and weight between birth and age 24 months; measures of social, verbal, and cognitive functioning at age 2 years. RESULTS: Compared with typically developing controls, boys with autism were significantly longer by age 4.8 months, had a larger HC by age 9.5 months, and weighed more by age 11.4 months (P = .05 for all). None of the other clinical groups showed a similar overgrowth pattern. Boys with autism who were in the top 10% of overall physical size in infancy exhibited greater severity of social deficits (P = .009) and lower adaptive functioning (P = .03). CONCLUSIONS: Boys with autism experienced accelerated HC growth in the first year of life. However, this phenomenon reflected a generalized process affecting other morphologic features, including height and weight. The study highlights the importance of studying factors that influence not only neuronal development but also skeletal growth in autism.

Autism spectrum disorders and epigenetics.

OBJECTIVE: Current research suggests that the causes of autism spectrum disorders (ASD) are multifactorial and include both genetic and environmental factors. Several lines of evidence suggest that epigenetics also plays an important role in ASD etiology and that it might, in fact, integrate genetic and environmental influences to dysregulate neurodevelopmental processes. The objective of this review is to illustrate how epigenetic modifications that are known to alter gene expression without changing primary DNA sequence may play a role in the etiology of ASD. METHOD: In this review, we summarize current knowledge about epigenetic modifications to genes and genomic regions possibly involved in the etiology of ASD. RESULTS: Several genetic syndromes comorbid with ASD, which include Rett, Fragile X, Prader-Willi, Angelman, and CHARGE (Coloboma of the eye, Heart defects, Atresia of the nasal choanae, Retardation of growth and/or development, Genital and/or urinary abnormalities, and Ear abnormalities and deafness), all demonstrate dysregulation of epigenetic marks or epigenetic mechanisms. We report also on genes or genomic regions exhibiting abnormal epigenetic regulation in association with either syndromic (15q11-13 maternal duplication) or nonsyndromic forms of ASD. Finally, we discuss the state of current knowledge regarding the etiologic role of environmental factors linked to both the development of ASD and epigenetic dysregulation. CONCLUSION: Data reviewed in this article highlight a variety of situations in which epigenetic dysregulation is associated with the development of ASD, thereby supporting a role for epigenetics in the multifactorial etiologies of ASD.