الأمراض الجينية (Genetic Disorders)

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Genetic Disorders

 

(Diseases)​​​​ 

On this page, you will find everything you need to know about genetic disorders. 

 

What Are Genetic Disorders? 

Genetic disorders are conditions caused by changes in the DNA sequence. These changes may result from a mutation in a single gene (monogenic disorder), mutations in multiple genes (multifactorial disorder), a combination of genetic mutations and environmental factors, or damage to chromosomes (which carry the genes).Some genetic disorders are inherited from the parents and are present at birth, such as sickle cell disease. Others result from acquired gene mutations during a person’s lifetime. These mutations are not inherited but occur due to random factors or environmental exposures such as chemicals, radiation, smoking, or ultraviolet rays from the sun. 

  • What Are the Typesof Genetic Disorders? 
  • There are three maintypes of genetic disorders: 
  • Single-gene disorders: Caused by amutation in one gene. 

 

Example: Sickle cell disease.

Chromosomal disorders: Occur when chromosomes (or parts of them) are missing or altered. Chromosomes are structures that carry genetic material. 

  • Example: Down syndrome. 
  • Complex disorders: Involve mutations in two or more genes. 
  • Example: Certain types of cancer. 
  • What Are the Symptoms of Genetic Disorders? 
  • Symptoms can vary widely depending on the type of disorder, affected organs, and severity. Common signs may include: 
  • Ear abnormalities. 
  • Unusual eye shape or different eye colors. 
  • Distinct facial features not seen in family members. 
  • Brittle, sparse, or patchy white hair. 
  • Enlarged or small tongue. 
  • Missing, extra, or malformed teeth. 
  • Loose or stiff joints. 
  • Webbed toes. 
  • Unusual birthmarks. 
  • Excessive or reduced sweating. 
  • Unusual body odor. 
  • Behavioral changes or disorders. 
  • Breathing difficulties. 
  • Cognitive impairment. 
  • Developmental delays (e.g., speech or social skills). 

 

Feeding and digestive problems (e.g., swallowing difficulties, nutrient absorption issues). 

Motor disorders due to muscle weakness or stiffness. 

  • Neurological issues (e.g.,seizures, stroke). 
  • Abnormal growth (shortor tall stature). 
  • Vision orhearing loss. 
  • What CausesGenetic Disorders? 
  • Causes vary depending on the typeof disorder. Key causes include: 

 

Gene mutations: Changes in the DNA sequence, inherited or acquired due to environmental exposures, can affect protein production and result in disorders. 

 

Inherited mutations: Passed down from one or both parents, present at birth, and can lead to specific diseases or conditions. 

Acquired mutations: Develop during life due to environmental factors like radiation, smoking, or chemicals. These are not inherited. 

  • Abnormal chromosome numbers: Some disorders occur when thereis an extra, missing, or misplaced chromosome. 
  • Example: Down syndrome (extracopy of chromosome 21). 

Complex disorders: Caused by a combination of multiple gene changes and environmental influences. 

  • Example: Some cancers. 
  • In summary, genetic disorders may be caused by inherited or acquired mutations,DNAabnormal chromosome numbers, or a combination of genetic and environmental factors. 

How Are Genetic Disorders Diagnosed?DTC):  

  • Diagnosis involves various genetic tests. The appropriate test depends on the individual’s symptoms, personal and family medical history. A healthcare provider can help select the proper test. Examples include: 
  • Single-gene testing: Examines changes in one specific gene. 
  • Used when symptoms suggest a known condition (e.g.,Duchenne muscular dystrophy, sickle cell disease) orDNAwhen there is a known family mutation. 
  • Panel testing: Checks for mutationsin several genes at once. 

 

Recommended for disorders with multiple possible genetic causes (e.g., primary immunodeficiency, epilepsy), or to assess cancer risk (e.g., breast or colon cancer genes). 

Broad genetic testing: 

 

Genetic sequencing: Examines all genes or those linked to a specific condition. 

Whole genome sequencing: Analyzes the entire DNA of an individual; used in complex medical cases when other tests are inconclusive. 

 

Clinical vs. direct-to-consumer (DTC) tests: 

Clinical testing: Ordered by a doctor for medical reasons.

DTC testing: Purchased online or in stores, primarily for ancestry or health insights, but not diagnostic on their own. 

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