Topic 2.7-2.8 - CF Treatments & Testing Flashcards
Name the five types of treatment currently available for CF.
Medication, Diet, Digestive Enzyme Supplements, Physiotherapy, and Heart and Lung Transplants.
How are scientists hoping to treat CF in the future?
Gene Therapy.
How does Gene Therapy treat CF?
Normal alleles for the target cells affected by the disease are inserted by a genetically modified virus or liposomes. The normal form of the gene is then transcribed and translated. Finally, the functioning protein is produced in the target cells.
How are genes inserted using a modified virus?
The DNA sequence that allows the virus to replicate is replaced with the normal allele. The patient is then infected with the virus, and the viral DNA is incorporated into the target cells’ DNA.
What are the downsides of using a modified virus to insert DNA?
Patients experience symptoms such as headache, fatigue, fever, and raised heartrate.
How are genes inserted using liposomes?
A copy of the normal allele is inserted into a plasmid. The plasmids are then combined with liposomes, which are spherical phospholipid bilayers. The positively charged heads of the phospholipids combine with the DNA to form a liposome-DNA complex. The patient inhales these complexes using a nebuliser. The liposomes fuse with epithelial cells, and the DNA is carried into the target cells.
What are somatic cells?
Body cells.
What are germ cells?
Sex cells.
What can genetic screening be used to identify?
Mutations in the CFTR gene (identifying CF) or abnormal alleles (identifying carriers).
Which two genetic screening techniques can be used to identify whether a foetus has CF?
Amniocentesis or Chorionic Villus Sampling (CVS).
Explain what happens during amniocentesis.
A needle is passed through the patient’s abdomen and uterus to collect a sample of amniotic fluid. This fluid will contain cells from the placenta and foetus that can be tested.
Explain what happens during CVS.
A needle is passed through the patient’s cervix to collect a sample of placental tissue to be tested.
At what point in the pregnancy can amniocentesis be carried out?
16 weeks onward.
At what point in the pregnancy can CVS be carried out?
After 9 weeks.
What is a downside to both amniocentesis and CVS?
They can both slightly increase the chance of a miscarriage. (Amniocentesis 1/100 - CVS 2/100).
