Genetic Mutations in Humans

Overview

• Genetic mutations are changes to the DNA sequence occurring during cell division.
• DNA provides the blueprint for body formation and function.
• Mutations may lead to genetic conditions like cancer or enhance adaptability over time.

What are Genetic Mutations?

• A genetic mutation involves changes in a DNA sequence.
• Incorrect or damaged DNA can result in genetic condition symptoms.

When and How do Genetic Mutations Occur?

• Mutations happen during cell division via:
  • Mitosis: Produces new body cells by splitting chromosomes.
  • Meiosis: Produces reproductive cells with halved chromosomes, contributing genetic material from both parents.
• Errors during cell division can substitute, delete, or insert DNA letters, affecting cell function.

Function of Genetic Mutations

• Changes cellular information, affecting protein production and characteristics.

• Symptoms depend on the mutated gene and may include:

  • Physical abnormalities (e.g., facial changes, cleft palate)
  • Cognitive delays
  • Sensory impairments
  • Breathing issues
  • Cancer risk

• Not all mutations are harmful; some have neutral effects or can be beneficial (e.g., resistance to disease).

Genetic Variations

• Mutations leading to permanent changes in DNA sequence create genetic variations.
• Beneficial mutations can enhance survival and be passed on, becoming part of the human genome.

Anatomy and Types of Genetic Mutations

• Genes, located on chromosomes within cells, define genetic makeup.

Types of Mutations:

• Germline mutation: Occurs in reproductive cells, heritable.
• Somatic mutation: Occurs post-conception, non-heritable.

Inheritance Patterns

• Mutations can follow different inheritance patterns:
  • Autosomal dominant: Only one parent needs to pass the mutation.
  • Autosomal recessive: Both parents must pass the same mutation.
  • X-linked dominant/recessive: Mutations on the X chromosome affect inheritance.
  • Y-linked: Passed through male lineage.
  • Codominant: Both parts of a gene independently affect traits.
  • Mitochondrial: Passed from maternal mitochondria.

Genetic Disorders

• Genetic disorders arise from genome changes and may be inherited or random.

Common Genetic Disorders

• Alzheimer’s disease
• Certain cancers
• Cystic fibrosis
• Down syndrome
• Sickle cell disease

Genetic Testing

• Tests identify gene or chromosome mutations, assessing risks of passing conditions to offspring.

Preventing Genetic Mutations

• Some mutations are random while others can be minimized by:
  • Avoiding smoking
  • Using sunscreen
  • Limiting chemical/radiation exposure
  • Maintaining a nutritious diet

Conclusion

• While some mutations cause genetic conditions, many are harmless.
• Genetic testing can help assess risks for future offspring.
• Cleveland Clinic offers genetics services for those interested in understanding hereditary risks.