Genetics Flashcards
What are the reasons for referral to genetics?
FH Diagnosis of genetic conditions Management of genetic conditions Genetic counselling -Aiding decision making -Increasing understandment
What are the different types of genetic screening?
Antenatal Neonatal Child Adult Pre-pregnancy In maturity
What is reproductive choice?
Nothing/test at birth Chorionic villus sampling Amniocentesis Pre-implantation genetic diagnosis (PGD) Adoption Gamete donation Non-invasive prenatal diagnosis and testing
What happens in an amnicentesis?
Amniotic fluid withdrawn and a karyotype is done
Can cause a miscarriage
What is non-invasive prenatal diagnosis and testing?
can be performed beginning around the 10th week of pregnancy
Small fragments of cell free DNA from the placenta enter the mothers bloodstream
This is then analysed for evidence of extra or missing fetal DNA segments
What is duchenne muscular dystrophy?
It is x-linked Fatal in early life Carrier testing Prenatal diagnosis Pre-implantation diagnosis
When is screening for downs syndrome done?
Maternal age Triple screening CUBS screeniong Selection for amniocentesis Free fetal DNA -Private @£500 -Coming to NHS -Needs checked
What are common disorders that raise screening issues?
CF Sickle cell disease Thalassaemias Tay-sachs disease Breast/ovarian cancer BRCA1
What is CF?
Defects of cellular chloride transport
Lung infections
Pancreatic insufficiency
Diagnosis = immunoreceptive trypsin, sweat test and genotyping
More than 1000 gene mutations cause disease
Some are common
90% in Scotland are detected with 25 mutation panel
What is Sickle cell?
Abnormal HB gene Sickle commonest UK Sickling -Pain -Cold, dehydration, infections -Jaundice, stroke, ulcers, eyes, kidney -Anaesthetic issues
What is Tay-Sachs disease?
Progressive, genetic, lysosomal storage disease
-Hex-A deficiency = build up of GM2 in nerve cells and brain
Usually develops normally until 6M then progressive neuro deterioration
Fatal by 3-5 years
Why do we screen babies?
Early detection of pre-symptomatic babies
Enables early treatment to improve health
To reduce anxiety
What do we screen babies for?
PKU Chronic hypothyroidism Sickle cell CF Medium chain acyl-CoA dehydrogenase deficiency Homocyeteinuria Isovaleric acidaemia Maple syrup urine disease Glutaric aciduria type 1
