Producing human proteins using genetic technology

Recombinant DNA technology is a technique to produce human proteins in bacterial, yeast, and mammalian cell cultures. It avoids the need for sourcing these proteins from animals or human donors.

This method offers numerous benefits:

• Cell cultures typically have simple nutritional requirements.
• They are capable of high-volume production.
• Minimal space is required for production.
• Production is feasible on a global scale.
• This eliminates risks associated with sources from humans or non-human animals.

Examples of uses of recombinant DNA technology

Several medically useful proteins can be produced using recombinant DNA technology.

1. Factor VIII

• This is a vital blood clotting factor produced in genetically modified hamster cells.
• These can be extracted and administered to individuals with haemophilia.
• This reduces the risk of disease transmission from human blood donations, which is the main alternative treatment.

1. Adenosine deaminase (ADA) enzyme

• This can be produced in bacteria and then injected into individuals with severe combined immunodeficiency (SCID).
• ADA then breaks down toxic deoxyadenosine in T lymphocytes, offering a treatment for the disorder.

1. Insulin

• This protein is vital in the treatment of many individuals with diabetes.
• Recombinant DNA technology enables the production of insulin in large quantities.
• This removes the reliance on animal-sourced diabetes treatment.

Genetic screening

Genetic screening involves analysing DNA to detect genes linked to diseases.

It can be conducted at various life stages, including before birth (prenatal testing) to detect genetic abnormalities early in pregnancy. This type of genetic screening enables prospective parents to better understand the risks of passing genetic diseases to their children.

Benefits of genetic screening:

• Facilitates early intervention and the adoption of prevention strategies.
• Informs family planning decisions.
• Identifies personalised treatment options, enhancing healthcare outcomes.

Ethical issues of genetic screening:

• It may reveal untreatable conditions, which could impact life quality.
• It may lead to embryo screening for non-medical traits, such as sex selection, raising ethical concerns.

Examples of uses of genetic screening

There are several examples of the applications of genetic screening in treating and preventing disease.

1. Cystic fibrosis (CF)

• Screening helps carriers understand the risk of their offspring inheriting CF.
• This means parents can make informed IVF decisions to prevent CF inheritance.

1.*** BRCA* genes**

• Screening can identify mutations in BRCA-1 and BRCA-2 genes.
• Mutations in these genes are associated with a higher risk of breast and ovarian cancers.
• This guides treatment to help prevent the development of these cancers.

Gene therapy for genetic diseases

Gene therapy involves treatment of genetic diseases by inserting functional genes into affected cells, often using viruses as vectors. Despite its promise, there are challenges in delivery of the functional genes into cells, and their durability.

Examples of genetic diseases treated with gene therapy:

1. SCID - Introducing the ADA gene into T lymphocytes or bone marrow stem cells allows them to function properly, improving immune function.
2. Leber congenital amaurosis - Introducing the functional dominant allele into individuals who are homozygous recessive for this gene allows the regeneration of pigments in retinal cells and prevents blindness.

Social and ethical issues with gene therapy

The potential health and economic benefits of gene therapy are significant, yet they also introduce ethical issues.

Concerns include:

• The potential for an immune response against the therapy.
• Ethical implications of modifying germline cells, which could have unknown effects on future generations.
• The research costs are high compared to the relatively small number of patients benefitting so far.
• There are challenges related to the efficacy and safety of gene therapy.
• Gene therapy introduces ethical dilemmas, like the risk of promoting eugenics by eliminating certain traits deemed 'inferior'.