Genetic Technology Applied to Medicine – Advantages of Genetic Screening
Genetic Technology Applied to Medicine
Objective
Outline the advantages of genetic screening, using the examples of breast cancer (BRCA1 and BRCA2), Huntington’s disease and cystic fibrosis.
Why Genetic Screening Is Important
Genetic screening involves testing individuals or populations for specific gene mutations that increase the risk of developing certain diseases. The main advantages are:
Early detection and intervention: Allows preventive measures before symptoms appear.
Informed reproductive choices: Couples can consider options such as pre‑implantation genetic diagnosis (PGD) or prenatal testing.
Targeted surveillance: High‑risk individuals receive more frequent and specialised monitoring.
Personalised treatment strategies: Therapies can be tailored to the genetic profile of the patient.
Psychological preparedness: Knowledge of risk can help individuals plan for the future.
Examples of Genetic Screening in Practice
1. Breast Cancer – BRCA1 and BRCA2
Mutations in the BRCA1 and BRCA2 genes significantly increase the lifetime risk of breast and ovarian cancer.
Risk assessment: Women carrying pathogenic variants have up to a 70% risk of developing breast cancer.
Preventive options: Prophylactic mastectomy, increased surveillance (annual MRI), and chemoprevention.
Family cascade testing: Relatives can be screened to identify other carriers.
2. Huntington’s Disease
Huntington’s disease (HD) is caused by an expanded CAG repeat in the HTT gene. It is an autosomal dominant neurodegenerative disorder.
Predictive testing: Allows individuals with a family history to know their status before symptom onset (average onset at age 30‑50).
Life planning: Enables decisions about career, finances, and family.
Research participation: Identified carriers can join clinical trials for emerging therapies.
3. Cystic Fibrosis
Cystic fibrosis (CF) results from mutations in the CFTR gene, most commonly the ΔF508 deletion.
Newborn screening: Early diagnosis leads to prompt treatment (physiotherapy, antibiotics, CFTR modulators) improving survival.
Carrier screening: Couples can be identified as carriers before conception, allowing informed reproductive choices.
Targeted therapy: Knowledge of the specific mutation guides use of drugs such as ivacaftor.
Summary Table of Advantages by Disease
Disease
Key Gene(s)
Primary Advantages of Screening
Breast Cancer
BRCA1, BRCA2
Early risk identification
Preventive surgery or chemoprevention
Enhanced surveillance protocols
Family cascade testing
Huntington’s Disease
HTT (CAG repeat expansion)
Predictive knowledge before symptoms
Informed life and career planning
Eligibility for clinical trials
Cystic Fibrosis
CFTR (e.g., ΔF508)
Newborn detection → early treatment
Carrier screening for reproductive decisions
Mutation‑specific drug selection
Suggested diagram: Flowchart showing the steps of genetic screening from sample collection to counselling and clinical action for each disease.
Key Take‑aways
Genetic screening provides crucial information that can dramatically alter disease outcomes.
Each disease benefits from specific screening strategies (e.g., population‑based, predictive, newborn).
Ethical considerations, such as informed consent and psychological support, are essential components of any screening programme.