Genetic disorders
Genetic disorders are diseases or medical conditions caused by abnormalities in GENES, CHROMOSOMES, or the GENOME that affect normal CELL FUNCTION and may be inherited from parents or occur due to new GENETIC MUTATIONS.
Genetic disorders are conditions that result from changes or abnormalities in an individual's GENETIC MATERIAL, including alterations in DNA, GENES, or CHROMOSOMES. These changes may occur due to GENETIC MUTATIONS, chromosomal changes, or variations affecting gene function and expression. Genetic disorders may be classified as SINGLE-GENE DISORDERS, CHROMOSOMAL DISORDERS, or MULTIFACTORIAL DISORDERS depending on their underlying cause. They can follow different patterns of INHERITANCE, including AUTOSOMAL DOMINANT, AUTOSOMAL RECESSIVE, and X-LINKED INHERITANCE. Examples include CYSTIC FIBROSIS, SICKLE CELL DISEASE, DOWN SYNDROME, and HEMOPHILIA. Diagnosis often involves GENETIC TESTING, CYTOGENETICS, and molecular techniques to identify genetic abnormalities.
Genetic disorders are health conditions caused by changes or mistakes in a person's genes or chromosomes that affect how the body grows or functions.
• Genetic disorders are caused by changes in genes, DNA, or chromosomes. • These changes can be inherited from parents or develop as new mutations. • They may affect body structure, development, metabolism, or normal cell functions. • Genetic disorders can involve a single gene, whole chromosomes, or multiple genetic and environmental factors. • Some common examples include Down syndrome, cystic fibrosis, sickle cell disease, and hemophilia. • They may follow different inheritance patterns such as dominant, recessive, or X-linked inheritance. • Diagnosis is performed using genetic testing and chromosome analysis. • Treatment depends on the disorder and may include medical management, gene-based therapies, and supportive care.
Genetic disorders are health conditions caused by changes (also called mutations or variants) in your genes. Genes are parts of DNA found in your cells that carry instructions for how your body grows, develops, and functions. Many genes tell your body how to make proteins, which are needed for your body to work properly.
What causes genetic disorders?A genetic disorder happens when a gene variant changes how a protein is made. The variant may cause the protein to work poorly or not be made at all. If genes don't make the right proteins, or don't make them correctly, it can lead to a genetic disorder.
Not all gene changes cause disease. Often, these changes have no effect. But sometimes, even a small change in DNA can affect how proteins are made.
Gene variants can be grouped into two main types:
- Inherited variants (also called germline variants) are passed down from your parents. They come from egg or sperm cells.
- Non-inherited (also called somatic variants) are not passed down from your parents. They happen during your lifetime. They may be caused by things like harmful chemicals or ultraviolet (UV) rays from the sun.
Genetic disorders may be caused by:
- Single gene disorders are caused by changes in one gene. Examples can include sickle cell anemia, where a change in a single gene can cause the condition, and Charcot-Marie-Tooth disease, where a variant in one of many different genes can cause the condition.
- Chromosomal disorders are caused by missing, extra, or altered chromosomes. Chromosomes are structures that carry genes. These disorders involve changes in the number of chromosomes people have or changes in the structure of one or more chromosomes. An example is Down syndrome, which is caused by an extra copy of chromosome 21.
- Complex (multifactorial) disorders are caused by changes in many genes. Each change alone may not cause the disease, but together they increase the risk. Lifestyle and environmental factors, such as exercise, diet, or exposure to pollutants, also play a role. Colon cancer is an example.
Some genetic conditions are passed down through families (inherited) in one of several patterns, depending on the specific gene involved.
Patterns of inheritance can include:
- Dominant means you only need one changed gene to cause the condition.
- Recessive means you need two changed copies of the gene (one from each parent) for the condition to occur.
- X-linked conditions involve genes located on the X chromosome. These conditions often affect males more frequently.
- Mitochondrial conditions are passed down by the mother.
Your health care provider may check for a genetic condition based on:
- A physical examination.
- Your personal medical history.
- Your family health history.
- Laboratory tests, including genetic testing.
NIH: National Library of Medicine
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