scholarly journals Screening for FMR1 CGG Repeat Expansion in Thai Patients with Autism Spectrum Disorder

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Areerat Hnoonual ◽  
Charunee Jankittunpaiboon ◽  
Pornprot Limprasert
Keyword(s):  
Autism Spectrum Disorder ◽  
Fragile X ◽  
Single Gene ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Fmr1 Gene ◽  
Normal Male ◽  
Cgg Repeat ◽  
Cgg Repeats ◽  
Normal Controls

Autism spectrum disorder (ASD) is a complex disorder with a heterogeneous etiology. Fragile X syndrome (FXS) is recognized as the most common single gene mutation associated with ASD. FXS patients show some autistic behaviors and may be difficult to distinguish at a young age from autistic children. However, there have been no published reports on the prevalence of FXS in ASD patients in Thailand. In this study, we present a pilot study to analyze the CGG repeat sizes of the FMR1 gene in Thai autistic patients. We screened 202 unrelated Thai patients (168 males and 34 females) with nonsyndromic ASD and 212 normal controls using standard FXS molecular diagnosis techniques. The distributions of FMR1 CGG repeat sizes in the ASD and normal control groups were similar, with the two most common alleles having 29 and 30 CGG repeats, followed by an allele with 36 CGG repeats. No FMR1 full mutations or premutations were found in either ASD individuals or the normal controls. Interestingly, three ASD male patients with high normal CGG and intermediate CGG repeats (44, 46, and 53 CGG repeats) were identified, indicating that the prevalence of FMR1 intermediate alleles in Thai ASD patients was approximately 1% while these alleles were absent in the normal male controls. Our study indicates that CGG repeat expansions of the FMR1 gene may not be a common genetic cause of nonsyndromic ASD in Thai patients. However, further studies for mutations other than the CGG expansion in the FMR1 gene are required to get a better information on FXS prevalence in Thai ASD patients.

scholarly journals Local Protein Translation and RNA Processing of Synaptic Proteins in Autism Spectrum Disorder

2021 ◽  
Vol 22 (6) ◽  
pp. 2811
Author(s):  
Yuyoung Joo ◽  
David R. Benavides
Keyword(s):  
Autism Spectrum Disorder ◽  
Fragile X ◽  
Single Gene ◽  
Protein Translation ◽  
Autism Spectrum ◽  
Repetitive Behaviors ◽  
Spectrum Disorder ◽  
Synaptic Proteins ◽  
Local Translation ◽  
Translation Control

Autism spectrum disorder (ASD) is a heritable neurodevelopmental condition associated with impairments in social interaction, communication and repetitive behaviors. While the underlying disease mechanisms remain to be fully elucidated, dysfunction of neuronal plasticity and local translation control have emerged as key points of interest. Translation of mRNAs for critical synaptic proteins are negatively regulated by Fragile X mental retardation protein (FMRP), which is lost in the most common single-gene disorder associated with ASD. Numerous studies have shown that mRNA transport, RNA metabolism, and translation of synaptic proteins are important for neuronal health, synaptic plasticity, and learning and memory. Accordingly, dysfunction of these mechanisms may contribute to the abnormal brain function observed in individuals with autism spectrum disorder (ASD). In this review, we summarize recent studies about local translation and mRNA processing of synaptic proteins and discuss how perturbations of these processes may be related to the pathophysiology of ASD.

scholarly journals Cerebral Expression of Metabotropic Glutamate Receptor Subtype 5 in Idiopathic Autism Spectrum Disorder and Fragile X Syndrome: A Pilot Study

2021 ◽  
Vol 22 (6) ◽  
pp. 2863
Author(s):  
James Robert Brašić ◽  
Ayon Nandi ◽  
David S. Russell ◽  
Danna Jennings ◽  
Olivier Barret ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Fragile X Syndrome ◽  
Glutamate Receptor ◽  
Metabotropic Glutamate Receptor ◽  
Fragile X ◽  
Single Gene ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Receptor Subtype ◽  
Metabotropic Glutamate

Multiple lines of evidence suggest that dysfunction of the metabotropic glutamate receptor subtype 5 (mGluR5) plays a role in the pathogenesis of autism spectrum disorder (ASD). Yet animal and human investigations of mGluR5 expression provide conflicting findings about the nature of dysregulation of cerebral mGluR5 pathways in subtypes of ASD. The demonstration of reduced mGluR5 expression throughout the living brains of men with fragile X syndrome (FXS), the most common known single-gene cause of ASD, provides a clue to examine mGluR5 expression in ASD. We aimed to (A) compare and contrast mGluR5 expression in idiopathic autism spectrum disorder (IASD), FXS, and typical development (TD) and (B) show the value of positron emission tomography (PET) for the application of precision medicine for the diagnosis and treatment of individuals with IASD, FXS, and related conditions. Two teams of investigators independently administered 3-[18F]fluoro-5-(2-pyridinylethynyl)benzonitrile ([18F]FPEB), a novel, specific mGluR5 PET ligand to quantitatively measure the density and the distribution of mGluR5s in the brain regions, to participants of both sexes with IASD and TD and men with FXS. In contrast to participants with TD, mGluR5 expression was significantly increased in the cortical regions of participants with IASD and significantly reduced in all regions of men with FXS. These results suggest the feasibility of this protocol as a valuable tool to measure mGluR5 expression in clinical trials of individuals with IASD and FXS and related conditions.

Putting Into Perspective the Use of the Fmr1 Knockout Mouse as a Model for Autism Spectrum Disorder

2013 ◽  
Author(s):  
Richard Paylor ◽  
Alexia M. Thomas ◽  
Surabi Veeraragavan ◽  
Corinne M. Spencer
Keyword(s):  
Autism Spectrum Disorder ◽  
Developmental Delay ◽  
Fragile X Syndrome ◽  
Knockout Mouse ◽  
Fragile X ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Fmr1 Gene ◽  
Not Otherwise Specified ◽  
Fmr1 Knockout Mouse

Chapter 7 is concerned with the presence of autism spectrum disorder (ASD) in individuals with Fragile X Syndrome (FXS). It is estimated that 21–50% of individuals with FXS meet the criteria for autism or autism with pervasive developmental delay not otherwise specified. Importantly, recent findings indicate that approximately 2–6% of individuals with ASDs have a mutation in the FMR1 gene, making it one of the most significant single genes associated with the presence of ASD.

scholarly journals Cascade Testing for Fragile X Syndrome in a Rural Setting in Cameroon (Sub-Saharan Africa)

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 136
Author(s):  
Karen Kengne Kamga ◽  
Séraphin Nguefack ◽  
Khuthala Minka ◽  
Edmond Wonkam Tingang ◽  
Alina Esterhuizen ◽  
...  
Keyword(s):  
Fragile X Syndrome ◽  
Fragile X ◽  
Autism Spectrum ◽  
Sub Saharan Africa ◽  
Rural Setting ◽  
Premature Menopause ◽  
Molecular Testing ◽  
Full Mutation ◽  
Cgg Repeat ◽  
Cgg Repeats

Fragile X Syndrome (FXS), an X-linked dominant monogenic condition, is the main genetic cause of intellectual disability (ID) and autism spectrum disorder (ASD). FXS is associated with an expansion of CGG repeat sequence in the Fragile X Mental Retardation gene 1 (FMR1) on chromosome X. Following a neuropediatric assessment of two male siblings who presented with signs of FXS that was confirmed with molecular testing, we provided cascade counselling and testing to the extended family. A total of 46 individuals were tested for FXS; among them, 58.70% (n = 27) were females. The mean age was 9.4 (±5) years for children and 45.9 (±15.9) years for adults. Pedigree analysis suggested that the founder of these families was likely a normal transmitting male. Four out of 19 males with clinical ID were confirmed to have a full mutation for FXS, while 14/27 females had a pathologic CGG expansion (>56 CGG repeats) on one of their X chromosomes. Two women with premature menopause were confirmed of being carriers of premutation (91 and 101 CGG repeats). We also identified maternal alleles (91 and 126 CGG repeats) which expanded to a full mutation in their offspring (>200 CGG repeats). This study is a rare report on FXS from Africa and illustrates the case scenario of implementing genetic medicine for a neurogenetic condition in a rural setting.

scholarly journals Towards Mechanism-Based Treatments for Fragile X Syndrome

2019 ◽  
Vol 9 (8) ◽  
pp. 202
Author(s):  
Daman Kumari ◽  
Inbal Gazy
Keyword(s):  
Autism Spectrum Disorder ◽  
Intellectual Disability ◽  
Fragile X Syndrome ◽  
Fragile X ◽  
Autism Spectrum ◽  
Spectrum Disorder

Fragile X syndrome (FXS) is the most common heritable form of intellectual disability, as well as the most common known monogenic cause of autism spectrum disorder (ASD), affecting 1 in 4000–8000 people worldwide [...]

scholarly journals Use of Emotional Cues for Lexical Learning: A Comparison of Autism Spectrum Disorder and Fragile X Syndrome

2014 ◽  
Vol 45 (4) ◽  
pp. 1042-1061 ◽  
Author(s):  
Angela John Thurman ◽  
Andrea McDuffie ◽  
Sara T. Kover ◽  
Randi Hagerman ◽  
Marie Moore Channell ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Fragile X Syndrome ◽  
Fragile X ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Emotional Cues ◽  
Lexical Learning
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