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Identification of mutations in the PI3K-AKT-mTOR signalling pathway in patients with macrocephaly and developmental delay and/or autism / K. S. YEUNG in Molecular Autism, 8 (2017)
[article]
Titre : Identification of mutations in the PI3K-AKT-mTOR signalling pathway in patients with macrocephaly and developmental delay and/or autism Type de document : Texte imprimé et/ou numérique Auteurs : K. S. YEUNG, Auteur ; W. W. Y. TSO, Auteur ; J. J. K. IP, Auteur ; C. C. Y. MAK, Auteur ; G. K. C. LEUNG, Auteur ; M. H. Y. TSANG, Auteur ; D. YING, Auteur ; S. L. C. PEI, Auteur ; S. L. LEE, Auteur ; W. YANG, Auteur ; B. H. CHUNG, Auteur Article en page(s) : 66p. Langues : Anglais (eng) Mots-clés : Autism spectrum disorder Developmental delay Mtor Macrocephaly Megalencephaly Pik3ca Ppp2r5d Pten Somatic mosaicism Hong Kong/Hospital Authority Hong Kong West Cluster (UW 12-211), and written consent was obtained from the patients' parents.Written informed consent was obtained from the patients' parents for publication of their children's details and accompanying images in this manuscript. The consent form is held by the authors and is available for review by the Editor-in-Chief.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Index. décimale : PER Périodiques Résumé : Background: Macrocephaly, which is defined as a head circumference greater than or equal to + 2 standard deviations, is a feature commonly observed in children with developmental delay and/or autism spectrum disorder. Although PTEN is a well-known gene identified in patients with this syndromic presentation, other genes in the PI3K-AKT-mTOR signalling pathway have also recently been suggested to have important roles. The aim of this study is to characterise the mutation spectrum of this group of patients. Methods: We performed whole-exome sequencing of 21 patients with macrocephaly and developmental delay/autism spectrum disorder. Sources of genomic DNA included blood, buccal mucosa and saliva. Germline mutations were validated by Sanger sequencing, whereas somatic mutations were validated by droplet digital PCR. Results: We identified ten pathogenic/likely pathogenic mutations in PTEN (n = 4), PIK3CA (n = 3), MTOR (n = 1) and PPP2R5D (n = 2) in ten patients. An additional PTEN mutation, which was classified as variant of unknown significance, was identified in a patient with a pathogenic PTEN mutation, making him harbour bi-allelic germline PTEN mutations. Two patients harboured somatic PIK3CA mutations, and the level of somatic mosaicism in blood DNA was low. Patients who tested positive for mutations in the PI3K-AKT-mTOR pathway had a lower developmental quotient than the rest of the cohort (DQ = 62.8 vs. 76.1, p = 0.021). Their dysmorphic features were non-specific, except for macrocephaly. Among the ten patients with identified mutations, brain magnetic resonance imaging was performed in nine, all of whom showed megalencephaly. Conclusion: We identified mutations in the PI3K-AKT-mTOR signalling pathway in nearly half of our patients with macrocephaly and developmental delay/autism spectrum disorder. These patients have subtle dysmorphic features and mild developmental issues. Clinically, patients with germline mutations are difficult to distinguish from patients with somatic mutations, and therefore, sequencing of buccal or saliva DNA is important to identify somatic mosaicism. Given the high diagnostic yield and the management implications, we suggest implementing comprehensive genetic testing in the PI3K-AKT-mTOR pathway in the clinical evaluation of patients with macrocephaly and developmental delay and/or autism spectrum disorder. En ligne : http://dx.doi.org/10.1186/s13229-017-0182-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=331
in Molecular Autism > 8 (2017) . - 66p.[article] Identification of mutations in the PI3K-AKT-mTOR signalling pathway in patients with macrocephaly and developmental delay and/or autism [Texte imprimé et/ou numérique] / K. S. YEUNG, Auteur ; W. W. Y. TSO, Auteur ; J. J. K. IP, Auteur ; C. C. Y. MAK, Auteur ; G. K. C. LEUNG, Auteur ; M. H. Y. TSANG, Auteur ; D. YING, Auteur ; S. L. C. PEI, Auteur ; S. L. LEE, Auteur ; W. YANG, Auteur ; B. H. CHUNG, Auteur . - 66p.
Langues : Anglais (eng)
in Molecular Autism > 8 (2017) . - 66p.
Mots-clés : Autism spectrum disorder Developmental delay Mtor Macrocephaly Megalencephaly Pik3ca Ppp2r5d Pten Somatic mosaicism Hong Kong/Hospital Authority Hong Kong West Cluster (UW 12-211), and written consent was obtained from the patients' parents.Written informed consent was obtained from the patients' parents for publication of their children's details and accompanying images in this manuscript. The consent form is held by the authors and is available for review by the Editor-in-Chief.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Index. décimale : PER Périodiques Résumé : Background: Macrocephaly, which is defined as a head circumference greater than or equal to + 2 standard deviations, is a feature commonly observed in children with developmental delay and/or autism spectrum disorder. Although PTEN is a well-known gene identified in patients with this syndromic presentation, other genes in the PI3K-AKT-mTOR signalling pathway have also recently been suggested to have important roles. The aim of this study is to characterise the mutation spectrum of this group of patients. Methods: We performed whole-exome sequencing of 21 patients with macrocephaly and developmental delay/autism spectrum disorder. Sources of genomic DNA included blood, buccal mucosa and saliva. Germline mutations were validated by Sanger sequencing, whereas somatic mutations were validated by droplet digital PCR. Results: We identified ten pathogenic/likely pathogenic mutations in PTEN (n = 4), PIK3CA (n = 3), MTOR (n = 1) and PPP2R5D (n = 2) in ten patients. An additional PTEN mutation, which was classified as variant of unknown significance, was identified in a patient with a pathogenic PTEN mutation, making him harbour bi-allelic germline PTEN mutations. Two patients harboured somatic PIK3CA mutations, and the level of somatic mosaicism in blood DNA was low. Patients who tested positive for mutations in the PI3K-AKT-mTOR pathway had a lower developmental quotient than the rest of the cohort (DQ = 62.8 vs. 76.1, p = 0.021). Their dysmorphic features were non-specific, except for macrocephaly. Among the ten patients with identified mutations, brain magnetic resonance imaging was performed in nine, all of whom showed megalencephaly. Conclusion: We identified mutations in the PI3K-AKT-mTOR signalling pathway in nearly half of our patients with macrocephaly and developmental delay/autism spectrum disorder. These patients have subtle dysmorphic features and mild developmental issues. Clinically, patients with germline mutations are difficult to distinguish from patients with somatic mutations, and therefore, sequencing of buccal or saliva DNA is important to identify somatic mosaicism. Given the high diagnostic yield and the management implications, we suggest implementing comprehensive genetic testing in the PI3K-AKT-mTOR pathway in the clinical evaluation of patients with macrocephaly and developmental delay and/or autism spectrum disorder. En ligne : http://dx.doi.org/10.1186/s13229-017-0182-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=331 In pursuit of neurophenotypes: The consequences of having autism and a big brain / David G. AMARAL in Autism Research, 10-5 (May 2017)
[article]
Titre : In pursuit of neurophenotypes: The consequences of having autism and a big brain Type de document : Texte imprimé et/ou numérique Auteurs : David G. AMARAL, Auteur ; Deana LI, Auteur ; Lauren LIBERO, Auteur ; Marjorie SOLOMON, Auteur ; Judy VAN DE WATER, Auteur ; Ann MASTERGEORGE, Auteur ; Letitia NAIGLES, Auteur ; Sally J ROGERS, Auteur ; Christine W. NORDAHL, Auteur Article en page(s) : p.711-722 Langues : Anglais (eng) Mots-clés : brain development magnetic resonance imaging megalencephaly phenotype subtypes Index. décimale : PER Périodiques Résumé : 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. En ligne : http://dx.doi.org/10.1002/aur.1755 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=307
in Autism Research > 10-5 (May 2017) . - p.711-722[article] In pursuit of neurophenotypes: The consequences of having autism and a big brain [Texte imprimé et/ou numérique] / David G. AMARAL, Auteur ; Deana LI, Auteur ; Lauren LIBERO, Auteur ; Marjorie SOLOMON, Auteur ; Judy VAN DE WATER, Auteur ; Ann MASTERGEORGE, Auteur ; Letitia NAIGLES, Auteur ; Sally J ROGERS, Auteur ; Christine W. NORDAHL, Auteur . - p.711-722.
Langues : Anglais (eng)
in Autism Research > 10-5 (May 2017) . - p.711-722
Mots-clés : brain development magnetic resonance imaging megalencephaly phenotype subtypes Index. décimale : PER Périodiques Résumé : 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. En ligne : http://dx.doi.org/10.1002/aur.1755 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=307 Increased Surface Area, but not Cortical Thickness, in a Subset of Young Boys With Autism Spectrum Disorder / Haruhisa OHTA in Autism Research, 9-2 (February 2016)
[article]
Titre : Increased Surface Area, but not Cortical Thickness, in a Subset of Young Boys With Autism Spectrum Disorder Type de document : Texte imprimé et/ou numérique Auteurs : Haruhisa OHTA, Auteur ; Christine W. NORDAHL, Auteur ; Ana-Maria IOSIF, Auteur ; Aaron LEE, Auteur ; Sally J ROGERS, Auteur ; David G. AMARAL, Auteur Article en page(s) : p.232-248 Langues : Anglais (eng) Mots-clés : cortical thickness surface area gray matter volume megalencephaly autism spectrum disorder FreeSurfer Index. décimale : PER Périodiques Résumé : The Autism Phenome Project is the largest, single site, longitudinal magnetic resonance imaging (MRI) study of young children with autism spectrum disorder (ASD). Previous analyses from this cohort have shown that the children with autism have a total brain volume at time 1 (?3 years of age) that is 6% larger than typically developing (TD) children. This finding is driven primarily by 15% of the boys with ASD that have disproportionate megalencephaly (ASD-DM) or brain size that is 1.5 standard deviations above what would be expected for the child's height. In the current study, cerebral cortical grey matter volume, thickness, and surface area were assayed from MRI scans of 112, 3-year-old boys with ASD and 50 age-matched TD boys. The boys with ASD-DM (n?=?17) were analyzed separately from the boys with normal brain size (ASD-N, n?=?95). Previous studies of cortical thickness and surface area for ASD children in this age range have come to diametrically different conclusions concerning the significance of cortical thickness vs. surface area. Current analyses indicate that cortical thickness was comparable across the ASD and TD groups. However, surface area was significantly greater in the ASD group compared to the TD group. This result was driven largely by the children with ASD-DM. Even in the ASD-DM group, not all cortical regions demonstrated increased surface area. These results provide strong evidence that the early cortical overgrowth associated with ASD is due primarily to increased surface area and not to increased cortical thickness. En ligne : http://dx.doi.org/10.1002/aur.1520 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=282
in Autism Research > 9-2 (February 2016) . - p.232-248[article] Increased Surface Area, but not Cortical Thickness, in a Subset of Young Boys With Autism Spectrum Disorder [Texte imprimé et/ou numérique] / Haruhisa OHTA, Auteur ; Christine W. NORDAHL, Auteur ; Ana-Maria IOSIF, Auteur ; Aaron LEE, Auteur ; Sally J ROGERS, Auteur ; David G. AMARAL, Auteur . - p.232-248.
Langues : Anglais (eng)
in Autism Research > 9-2 (February 2016) . - p.232-248
Mots-clés : cortical thickness surface area gray matter volume megalencephaly autism spectrum disorder FreeSurfer Index. décimale : PER Périodiques Résumé : The Autism Phenome Project is the largest, single site, longitudinal magnetic resonance imaging (MRI) study of young children with autism spectrum disorder (ASD). Previous analyses from this cohort have shown that the children with autism have a total brain volume at time 1 (?3 years of age) that is 6% larger than typically developing (TD) children. This finding is driven primarily by 15% of the boys with ASD that have disproportionate megalencephaly (ASD-DM) or brain size that is 1.5 standard deviations above what would be expected for the child's height. In the current study, cerebral cortical grey matter volume, thickness, and surface area were assayed from MRI scans of 112, 3-year-old boys with ASD and 50 age-matched TD boys. The boys with ASD-DM (n?=?17) were analyzed separately from the boys with normal brain size (ASD-N, n?=?95). Previous studies of cortical thickness and surface area for ASD children in this age range have come to diametrically different conclusions concerning the significance of cortical thickness vs. surface area. Current analyses indicate that cortical thickness was comparable across the ASD and TD groups. However, surface area was significantly greater in the ASD group compared to the TD group. This result was driven largely by the children with ASD-DM. Even in the ASD-DM group, not all cortical regions demonstrated increased surface area. These results provide strong evidence that the early cortical overgrowth associated with ASD is due primarily to increased surface area and not to increased cortical thickness. En ligne : http://dx.doi.org/10.1002/aur.1520 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=282