Inherited diseases, embryonic screening and gene therapy

What are inherited disorders?

Inherited disorders are genetic conditions caused by faulty alleles that can be passed from parents to offspring through genes.

• Some disorders are caused by dominant alleles, while others are caused by recessive alleles.

What is cystic fibrosis, and how is it inherited?

Cystic fibrosis (CF) is a recessive genetic disorder that affects the lungs and digestive system by producing thick, sticky mucus.

What is polydactyly, and how is it inherited?

• Polydactyly is a disorder that causes a person to have extra fingers or toes. ( however this can easily be removed through surgery)

• It is caused by a dominant allele (P), meaning only one copy is needed for the disorder to be present.

What is embryonic screening?

Embryonic screening is a process used to test embryos for genetic disorders before implantation or birth.

What are the two types of genetic screening?

1. Pre-implantation Genetic Diagnosis (PGD)

• Used in IVF before implantation.

• Only healthy embryos are implanted into the mother.

2. Prenatal Testing (Amniocentesis & CVS)

• Used to test for genetic conditions in a developing fetus.

• Amniocentesis – Sample of amniotic fluid taken at 15-20 weeks of pregnancy. ( risky as can cause a miscarriage)

What are the advantages of embryonic screening?

1. gives mum a choice

2. reduction in the prevalence of a disease in a population

3. saves NHS money as treatment and research of genetic disorders is expensive

4. can avoid sufferring by stopping children being born with genetic disorders

5. there are laws in place to stop embryo screening being abused so that parents don’t choose embryos with desirable trait

What are the disadvantages and ethical concerns of embryonic screening?

1. the process implies that people with genetic disorders are undesirable

2. it’s very expensive and therefore not accessible to everyone

3. Could lead to ‘designer babies’ – Risk of choosing babies with desirable traits

What is gene therapy?

Gene therapy is a technique that replaces faulty genes with healthy ones to treat genetic disorders.

What are the advantages of gene therapy?

Potential cure for genetic diseases – Unlike medicines, it fixes the problem at the source.
Could save lives – Helps patients with fatal conditions.
Reduces symptoms – Improves quality of life for patients with disorders like cystic fibrosis.

What are the disadvantages of gene therapy?

1. many believe that gene alteration is unnatural

2. Expensive – Not widely available.

3. Unpredictable long-term effects – The inserted gene may not work properly as it’s still relatively experimental