Genetic testing in patients with nonsyndromic autism spectrum disorder and EEG abnormalities with or without epilepsy: Is exome trio-based testing the best clinical approach?

Abstract Background: Autism Spectrum Disorder (ASD) is a highly heritable polygenetic disorder with several degrees of handicap.Novel genetic diagnostics for Autism Spectrum Disorder promise an earlier diagnosis than psychometric diagnostics, but their cost-effectiveness is unproven.Objective: To model the clinical pathway from diagnosis to early intervention (EI) and outcome in scenarios with genetic diagnostics compared to just psychometric diagnosis that follows a current guideline (Status Quo). Methods: Early diagnosis based on genetic testing leads to more intensive and effective early intervention. Future scenarios assume genetic screening(Screening), genetic testing on request(GenADD), or genetic testing in cases with a family history of ASD(Predisposition). Simulations on Markov models using software TreeAge v. 2018 and parameters found in the literature. The time horizon reached from birth to the 15th year of life with cycle length 1 year. The models were stratified by autism severity, i.e. IQ initially below 70 or above. Effectiveness was both, dependency free life years (DFLY) gained by correct diagnosis and successful treatment, and the number of diagnosed patients that became independent after treatment. We choose the insurance view. Just direct costs for diagnostics and treatment were considered. Probabilistic sensitivity analyses (PSA) explore assumptions of different parameters, like the sensitivity of the genetic test, using the precisions stated in the literature or possible future developments. Results: Status Quo is the most cost-effective scenario with the current parameter values. The other scenarios follow in the order of Predisposition, GenADD, and Screening. All scenarios with genetic tests have a higher number of detection than Status Quo. Intensified early intervention may be cost effective with horizon 67 years. The currently high false positive rate of genetic testing might be detrimental to that. Discussion: Low precision of published parameter estimates led to wide confidence intervals for our estimates of cost-effectiveness. Our model shows that Screening and GenADD should not be an option for inaccurate genetic tests. Once they are more accurate, the potential of early intervention may unfold.Conclusion: Further evaluations with better data need to underpin the current results.

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Cellular and behavioral effects of altered NaV1.2 sodium channel ion permeability in Scn2aK1422E mice

10.1101/2021.07.19.452930 ◽

2021 ◽

Author(s):

Dennis M Echevarria-Cooper ◽

Nicole A Hawkins ◽

Sunita N Misra ◽

Alexandra Huffman ◽

Tyler Thaxton ◽

...

Keyword(s):

Autism Spectrum Disorder ◽

Action Potential ◽

Sodium Channel ◽

Developmental Delay ◽

Neuronal Excitability ◽

Autism Spectrum ◽

Mixed Effects ◽

Spectrum Disorder ◽

Channel Function ◽

Eeg Abnormalities

Genetic variants in SCN2A, encoding the NaV1.2 voltage-gated sodium channel, are associated with a range of neurodevelopmental disorders with overlapping phenotypes. Some variants fit into a framework wherein gain-of-function missense variants that increase neuronal excitability lead to infantile epileptic encephalopathy, while loss-of-function variants that reduce neuronal excitability lead to developmental delay and/or autism spectrum disorder with or without co-morbid seizures. One unique case less easily classified using this binary paradigm is the de novo missense variant SCN2A-p.K1422E, associated with infant-onset developmental delay, infantile spasms, and features of autism spectrum disorder. Prior structure-function studies demonstrated that K1422E substitution alters ion selectivity of NaV1.2, conferring Ca2+ permeability, lowering overall conductance, and conferring resistance to tetrodotoxin (TTX). Based on heterologous expression of K1422E, we developed a compartmental neuron model that predicted mixed effects on channel function and neuronal activity. We also generated Scn2aK1422E mice and characterized effects on neurons and neurological/neurobehavioral phenotypes. Dissociated neurons from heterozygous Scn2aK1422E/+ mice exhibited a novel TTX-resistant current with a reversal potential consistent with mixed ion permeation. Cortical slice recordings from Scn2aK1422E/+ tissue demonstrated impaired action potential initiation and larger Ca2+ transients at the axon initial segment during the rising phase of the action potential, suggesting mixed effects on channel function. Scn2aK1422E/+ mice exhibited rare spontaneous seizures, interictal EEG abnormalities, altered response to induced seizures, reduced anxiety-like behavior and alterations in olfactory-guided social behavior. Overall, Scn2aK1422E/+ mice present with phenotypes similar yet distinct from Scn2a knockout models, consistent with mixed effects of K1422E on NaV1.2 channel function.

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What are the Informational Preferences about Genetic Testing of Parents with Children with Autism Spectrum Disorder?

Paediatrics & Child Health ◽

10.1093/pch/pxy054.097 ◽

2018 ◽

Vol 23 (suppl_1) ◽

pp. e37-e37

Author(s):

Fanny Lacelle-Webster ◽

Rinita Mazumder ◽

Sandy Hodgetts ◽

Lonnie Zwaigenbaum

Keyword(s):

Autism Spectrum Disorder ◽

Genetic Testing ◽

Online Survey ◽

Demographic Data ◽

Insurance Coverage ◽

Structured Interview ◽

Autism Spectrum ◽

Spectrum Disorder ◽

Children With Asd ◽

Almost All

Abstract BACKGROUND Autism Spectrum Disorder (ASD) affects more than 1% of the population. In 2009, the Canadian College of Medical geneticists recommended genome-wide microarray analysis as a first-line investigation for children with a diagnosis of ASD. OBJECTIVES The purpose of this study is to explore experiences and preferences of parents with children with ASD regarding information about genetic testing. DESIGN/METHODS In this mixed method study, parents of children with a diagnosis of ASD (age 2 to 17 years) were recruited through advertisements on websites and Facebook pages of community partners. The first step was an on-line survey housed on a secure web-based platform. In addition to demographic data, the survey collected information about the experiences and informational preferences of the parents about genetic testing. A subset of participants, based on expressed interest, participated in an in-person semi-structured interview. All interviews were recorded, transcribed and coded for major themes and sub-themes. RESULTS A total of 31 participants responded to the survey and 5 interviews were completed. Their children had received their diagnosis between 2004 and 2017. The online survey revealed that 69% of participants were aware of genetic testing and 38% had genetic testing completed. Overall, 94% wanted to have more information about genetic testing; notably, only 25% had heard about microarray. Receiving information about genetic testing was preferred in a follow up appointment by 56% of participants, but 28% preferred to receive information on the date of ASD diagnosis. Most participants (81%) identified their community paediatrician as the preferred physician to discuss genetic testing with them. Almost all interview participants were concerned that the information from genetic testing could be detrimental to their child, noting, for example, potential difficulties obtaining insurance coverage. Some shared their concerns regarding their paediatrician’s knowledge about genetic testing and ASD; in fact, two families decided to change to a new paediatrician to fulfill their needs of information about ASD and genetic testing. CONCLUSION This study showed that parents of children with ASD are globally interested to learn more about genetic testing, with their paediatrician being their preferred resource. For that reason, it appears important that paediatricians be aware of the recommended investigations for children with ASD and have a good understanding of the implications of genetic testing.

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Electroencephalographic Abnormalities in Autism Spectrum Disorder: Characteristics and Therapeutic Implications

Medicina ◽

10.3390/medicina56090419 ◽

2020 ◽

Vol 56 (9) ◽

pp. 419

Author(s):

Francesco Precenzano ◽

Lucia Parisi ◽

Valentina Lanzara ◽

Luigi Vetri ◽

Francesca Felicia Operto ◽

...

Keyword(s):

Autism Spectrum Disorder ◽

State Of The Art ◽

Large Body ◽

Autism Spectrum ◽

Spectrum Disorder ◽

Major Research ◽

Therapeutic Implications ◽

Epileptiform Discharges ◽

Eeg Abnormalities ◽

Research Findings

A large body of literature reports the higher prevalence of epilepsy in subjects with Autism Spectrum Disorder (ASD) compared to the general population. Similarly, several studies report an increased rate of Subclinical Electroencephalographic Abnormalities (SEAs) in seizure-free patients with ASD rather than healthy controls, although with varying percentages. SEAs include both several epileptiform discharges and different non-epileptiform electroencephalographic abnormalities. They are more frequently associated with lower intellectual functioning, more serious dysfunctional behaviors, and they are often sign of severer forms of autism. However, SEAs clinical implications remain controversial, and they could represent an epiphenomenon of the neurochemical alterations of autism etiology. This paper provides an overview of the major research findings with two main purposes: to better delineate the state-of-the-art about EEG abnormalities in ASD and to find evidence for or against appropriateness of SEAs pharmacological treatment in ASD.

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Genetic evaluation of children with autism spectrum disorders in developing and low-resource areas

Autism ◽

10.1177/13623613211055535 ◽

2021 ◽

pp. 136236132110555

Author(s):

Amira T Masri ◽

Arwa Nasir ◽

Fatima Irshaid ◽

Farah Alomari ◽

Aya Irshaid ◽

...

Keyword(s):

Autism Spectrum Disorder ◽

Genetic Testing ◽

Clinical Guidelines ◽

Genetic Factors ◽

Neurodevelopmental Disorder ◽

Children With Autism ◽

Autism Spectrum ◽

Spectrum Disorder ◽

Convenience Sample ◽

Low Resource

Autism spectrum disorder is a neurodevelopmental disorder in which genetic factors play key roles. Limited research has been conducted on genetic testing of children with autism spectrum disorder in low middle-income countries. This prospective cross-sectional study was conducted at the pediatric neurology clinics of three university hospitals in Jordan. Data were obtained from a convenience sample of parents of children with autism spectrum disorder who received care at these hospitals. Research personnel interviewed the parents and completed a questionnaire. A total of 274 parents were interviewed. A minority of children received chromosomal microarray (14.6%) or fragile X syndrome (4.4%) testing, as recommended by clinical guidelines. Karyotyping was performed in 103 (37.6%) patients, and whole-exome sequencing was performed in 9 (3.3%). The most common reason for not performing the recommended diagnostic investigations was that they were not ordered by the physician (185; 67.5%). The majority of children underwent non-genetic evaluations, including brain magnetic resonance imaging (222; 81.0%), electroencephalogram (221; 80.7%), and brain computed tomography scans (136; 49.6%). Only a minority of children with autism spectrum disorder in Jordan receive genetic workup, which may reflect a gap in physicians’ knowledge of clinical guidelines, as well as the availability and affordability of these tests. Lay abstract Autism is the most common neurodevelopmental disorder in children worldwide. Genetic factors play an important role in the risk of developing autism. Determining the genetic cause of autism is key to understanding the biological processes that lead to the clinical manifestations of autism, and can inform the management and even prevention of this condition. Establishing genetic causes of autism requires collection of genetic data on a global scale. Limited research on genetic testing for individuals with autism is available from developing countries in low-resource regions. In this study, we explored the types of investigations ordered for Jordanian children with autism by their physicians. A representative sample of parents of children with autism in Jordan was questioned about the studies that their children received. We found that the recommended genetic testing was only performed in a small number of children with autism. In contrast, most children in the sample received non-genetic testing, which is not routinely recommended. We also explored the sociocultural factors that may influence the decision to perform genetic testing in this population. We discuss our findings in light of the data available from other developing and developed countries.

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