Related Concept Videos
01:19Autism Spectrum Disorder
Autism spectrum disorder (ASD) is a neurodevelopmental condition marked by persistent deficits in social communication and interaction alongside restrictive and repetitive behaviors or interests. ASD is sometimes accompanied by intellectual impairment.
These core symptoms manifest differently among individuals, ranging from mild to severe. The disorder's complexity extends beyond its clinical presentation, encompassing a diverse range of biological, cognitive, and sociocultural influences.
These core symptoms manifest differently among individuals, ranging from mild to severe. The disorder's complexity extends beyond its clinical presentation, encompassing a diverse range of biological, cognitive, and sociocultural influences.
01:29Drugs Affecting Neurotransmitter Synthesis
Drugs affecting neurotransmitter synthesis can impact the adrenergic neuron and the synthesis of neurotransmitters. For example, α-methyltyrosine and carbidopa target specific enzymes involved in catecholamine synthesis. α-methyltyrosine inhibits the enzyme tyrosine hydroxylase, which converts tyrosine into dopamine. By blocking this enzyme, α-methyltyrosine reduces dopamine production and other catecholamines. Carbidopa, on the other hand, inhibits the enzyme dopa decarboxylase, which converts...
01:43Sex Linked Disorders
Like autosomes, sex chromosomes contain a variety of genes necessary for normal body function. When a mutation in one of these genes results in biological deficits, the disorder is considered sex-linked.
01:30Attention-Deficit/Hyperactivity Disorder
Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by persistent inattention, hyperactivity, and impulsivity. It affects approximately 5-8% of children globally, with around 60-70% of cases persisting into adulthood. ADHD has significant implications for educational attainment, social interactions, and occupational success.
Diagnostic Criteria and Symptoms
To diagnose ADHD, symptoms must manifest before age 12 and be evident across multiple settings.
Diagnostic Criteria and Symptoms
To diagnose ADHD, symptoms must manifest before age 12 and be evident across multiple settings.
01:28Electrical Synapses
Electrical synapses found in all nervous systems play important and unique roles. In these synapses, the presynaptic and postsynaptic membranes are very close together (3.5 nm) and are actually physically connected by channel proteins forming gap junctions.
Gap junctions allow the current to pass directly from one cell to the next. In contrast, in the chemical synapse, the neurotransmitters carry the information through the synaptic cleft from one neuron to the next. They consist of two...
Gap junctions allow the current to pass directly from one cell to the next. In contrast, in the chemical synapse, the neurotransmitters carry the information through the synaptic cleft from one neuron to the next. They consist of two...
01:29Biological Causes of Schizophrenia
Schizophrenia, a severe psychiatric disorder, arises from a complex interplay of biological factors, including genetic predisposition, structural brain abnormalities, neurotransmitter dysregulation, and developmental irregularities. These factors collectively contribute to the onset and progression of the disorder, which typically manifests in late adolescence or early adulthood.
Genetic Factors in Schizophrenia
The genetic basis of schizophrenia is strongly supported by family and twin studies.
Genetic Factors in Schizophrenia
The genetic basis of schizophrenia is strongly supported by family and twin studies.
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Published on: October 17, 2025
A synaptic trek to autism.
1Human Genetics and Cognitive Functions, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France. thomasb@pasteur.fr
Current Opinion in Neurobiology
|June 24, 2009
Summary
Autism spectrum disorders (ASD) involve social communication deficits and stereotypy. Genetic mutations affecting synaptic pathways, like mTOR/PI3K and NRXN-NLGN-SHANK, are key risk factors for ASD.
Area of Science:
- Neuroscience
- Genetics
- Developmental disorders
Background:
- Autism spectrum disorders (ASD) are characterized by social communication deficits, language delays, and stereotyped behaviors.
- The genetic underpinnings of ASD are complex, with emerging evidence pointing to specific molecular pathways.
- Two prominent pathways implicated in ASD are the mTOR/PI3K pathway and the NRXN-NLGN-SHANK synaptic pathway.
Purpose of the Study:
- To review and synthesize current knowledge on genetic pathways associated with Autism Spectrum Disorders.
- To highlight the roles of the mTOR/PI3K and NRXN-NLGN-SHANK pathways in ASD pathogenesis.
- To propose abnormal synaptic homeostasis as a central risk factor for ASD.
Main Methods:
- Literature review of genetic studies and pathway analysis in Autism Spectrum Disorders.
Main Results:
- Mutations in TSC1/TSC2, NF1, or PTEN activate the mTOR/PI3K pathway, leading to syndromic ASD with conditions like tuberous sclerosis.
- Mutations in NLGN3/4, SHANK3, or NRXN1 disrupt synaptic function, associated with intellectual disability and autism.
- The mTOR/PI3K pathway is linked to abnormal cellular and synaptic growth rates.
- The NRXN-NLGN-SHANK pathway is associated with synaptogenesis and excitatory/inhibitory imbalance.
Conclusions:
- The mTOR/PI3K pathway influences cellular and synaptic growth rates in ASD.
- The NRXN-NLGN-SHANK pathway is crucial for synaptogenesis and maintaining neural circuit balance.
- Aberrant synaptic homeostasis, influenced by these genetic pathways, represents a significant risk factor for developing Autism Spectrum Disorders.