Genetics Flashcards
What prenatal investigations can be used to look at genetics?
Amniocentesis
Chorionic villus sampling
What are the features of autosomal dominant inheritance?
Each child has 50% chance of inheriting mutation
No “skipped generation”
Equally transmitted by men and women
What are some common recessive disorders that raise screening issues?
North Europe cystic fibrosis African sickle cell disease Mediterranean and Asian thalassaemias Ashkenazi Jews Tay-Sachs disease Breast ovarian cancer BRAC1 CF W1282X
What is cystic fibrosis?
Defect of cellular chloride transporter (CFTR)
How is a cystic fibrosis diagnosis made?
Immunoreactive trypsin (6 wks)
Sweat test
Genotyping
What is sickle cell disease?
Abnormal Hb gene
What are the effects of sickle cell disease?
Pain
Cold, dehydration, infections
Jaundice, stoke, leg ulcers
Anaesthetic issues
What is Tay-Sachs disease?
Progressive genetic lysosomal storage disease
Hexoaminidase A deficiency results in build up of lipid GM ganglioside
What particular group are associated with Tay-Sachs disease?
Ashkenazi Jews (1 in 25 are carriers)
What is screened for in the newborn screening programme?
Phenylketonuria (PKU) Congenital hypothyroidism Sickle cell disorders Cystic fibrosis Maple syrup urine disease Medium chain acyl-CoA dehydogenase deficiency
What is phenylketonuria?
Babies are unable to break down phenylalanine (amino acid in protein)
How is PKU treated?
Early treatment with a strictly controlled diet prevents disability
What is congenital hypothyroidism?
Not enough thyroxine
What is the treatment for congenital hypothyroidism?
Early treatment with thyroxine tablets
What is MCADD?
Cannot easily break down fats to make energy for the body
