Concept
CAG repeats refer to a sequence of three DNA nucleotides (cytosine, adenine, and guanine) that are repeated multiple times in a row within certain genes. The expansion of these repeats beyond a normal range is associated with several neurodegenerative diseases, including Huntington's disease, by affecting the function and structure of the proteins they encode.
Relevant Fields:
Trinucleotide repeat expansion is a genetic mutation where specific sequences of three nucleotides are repeated excessively, leading to various hereditary disorders. This phenomenon can cause diseases such as Huntington's disease and fragile X syndrome, where the number of repeats correlates with disease severity and onset.
Concept
Huntington's disease is a hereditary neurodegenerative disorder characterized by progressive motor dysfunction, cognitive decline, and psychiatric symptoms, resulting from a mutation in the HTT gene on chromosome 4. It typically manifests in mid-adulthood and is inherited in an autosomal dominant pattern, meaning each child of an affected parent has a 50% chance of inheriting the mutation.
Concept
Neurodegenerative diseases are a diverse group of disorders characterized by progressive degeneration of the structure and function of the nervous system, often leading to debilitating symptoms and a decline in cognitive and motor functions. These diseases, including Alzheimer's, Parkinson's, and ALS, are typically associated with aging, and their exact causes and mechanisms remain subjects of intensive research, focusing on genetic, environmental, and molecular factors.
Concept
Genetic mutation refers to a change in the DNA sequence that can lead to variations in the genetic code, potentially causing alterations in an organism's traits or functions. Mutations can occur naturally during DNA replication or be induced by environmental factors, and they play a crucial role in evolution, genetic diversity, and sometimes in genetic disorders.
Concept
Polyglutamine diseases are a group of neurodegenerative disorders caused by the abnormal expansion of CAG trinucleotide repeats in certain genes, leading to the production of proteins with elongated polyglutamine tracts. This expansion results in protein misfolding, aggregation, and subsequent neuronal dysfunction and death, manifesting in conditions like Huntington's disease and various spinocerebellar ataxias.
Concept
A DNA sequence is a specific linear arrangement of nucleotides (adenine, thymine, cytosine, and guanine) that encodes the genetic information of an organism. This sequence determines the synthesis of proteins and regulates various biological processes, impacting traits and functions at the cellular and organismal levels.
Concept
Protein misfolding occurs when proteins fail to achieve their native three-dimensional structures, leading to loss of function and potentially harmful aggregates. This process is implicated in various diseases, including Alzheimer's, Parkinson's, and prion diseases, where misfolded proteins disrupt cellular functions and trigger pathological cascades.
Concept
Gene expression is the process by which information from a gene is used to synthesize a functional gene product, typically proteins, which ultimately determine cellular function and phenotype. This process is tightly regulated at multiple levels, including transcription, RNA processing, translation, and post-translational modifications, to ensure proper cellular function and response to environmental cues.
Concept
Molecular genetics is the field of biology that studies the structure and function of genes at a molecular level, utilizing techniques like DNA sequencing and recombinant DNA technology. It provides insights into genetic expression, mutation, and regulation, which are crucial for understanding genetic diseases and developing targeted therapies.
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