Gene therapy is the insertion of a normal allele of a gene into cells to replace a faulty allele that causes an inherited disorder. This could be done in the very early embryo (germ line therapy) or in the affected body parts (somatic therapy)
- Step 1- identify the gene involved, for example the gene for CF is found on chromosome 7.
- Step 2- make copies of the normal allele and insert into a vector- the two most common vectors for human cells are viruses and lipsomes.
- Step 3- use the vector to insert the allele into the target cells.
Trials of gene therapy for CF have successfully transferred the normal CFTR allele to the epithelial cells in the lungs of CF patients. After insertion of the normal allele into the genome of the target cell it can make the functioning CFTR and therefore allow normal chloride movement.
Avoidance and early treatment
- Avoid having a child with such a condition
- Start treatment immediately after birth.
These options may involve genetic screening, which includes:
- Newborn babies could be tested for faulty alleles of CF gene, however the CF gene has many mutations and no test can cover all of them, so a negative result could be false.
- DNA testing of adults to identify carriers.
- Pre-natal DNA testing of embryonic cells using amniocentesis or chronionic villus sampling so parents can decided whether to have the baby or not.
- PGID, embryo created through in vitro fertilisation (IVF) and is tested to see if they carry the faulty allele, only those which do not are implanred into the woman.