lecture 10; biomedical genetics

Question 1

what is an IEM

Answer 1

inborn error of metabolism

Question 2

how do we classify IEMs

Answer 2

• identifying which metabolites are high or low
• identify which pathway is disrupted
• enzyme; which is not working
• organelle involved; where abouts in the cell is it

Question 3

diagnostic tests for IEMs

Answer 3

• screening tests
• stress tests
• specific assays
• post mortem protocol

Question 4

which of these diagnostic tests would you use to detect many conditions

Answer 4

screening tests

Question 5

which of these diagnostic tests would you use when there is an idea for a disease

Answer 5

specific assays

Question 6

what are urea cycle defects

Answer 6

affect the bodies ability to remove ammonia from the bloodstream

failure to breakdown amino acids means they remain in the body as ammonia and this buildup of ammonia can cause brain damage, coma and if untreated can be fatal

Question 7

symptoms of urea cycle defects

Answer 7

poor feeding
vomiting
seizures
lethargy (lack of energy)

Question 8

what can be done to treat urea cycle defects

Answer 8

bringing the level of protein down with a high carb, low protein diet

Question 9

phenylketonuria

Answer 9

disorder resulting from the lack of phenylalanine hydroxylase (PAH)

the lack of PAH leads to a build up of phenylalanine in the blood and brain causing health problems

Question 10

if phenylketonuria is untreated what can it cause

Answer 10

dev. delays
seizures
behavioral problems

Question 11

how is phenylketonuria treated

Answer 11

diet low in phenylalanine which involves restricting foods high in protein

Question 12

treatment of IEMs

Answer 12

• decrease substrate
• excrete toxic metabolite
• replenish missing product
• increase substrate
• block production of toxic metabolites

Question 13

how would you decrease the substrate

Answer 13

dietary restriction of substrate
- Management of PKU typically involves reducing the intake of dietary phenylalanine through a special low-protein diet a

prevent absorption of substrate from gut

Question 14

examples of replenishing the missing product as a treatment of IEMs

Answer 14

• give carbs in glycogen storage disease
• give tyrosine in PKU
• give intermediates in urea cycle

Question 15

talk about increasing the substrate as a method of treatment for IEMs

Answer 15

usually used when the metabolic pathway is blocked by the deficiency of an enzyme

Question 16

name a lysosomal storage disorder

Answer 16

Hunter Syndrome also known as MPS II

Question 17

what is the cause of Hunter syndrome/MPS II

Answer 17

accumulation of glycosaminoglycan

Question 18

What is a way of treating MPS II/ Hunter Syndrome

Answer 18

treatment with bone marrow transplant can reduce symptoms

Question 19

lipoprotein metabolism - familial hypercholesterolemia

Answer 19

rare autosomal dominant type of disorder characterised by high levels of low- density lipoprotein cholesterol in the blood

Question 20

lipoprotein metabolism link to coronary artery disease

Answer 20

50% of males and 25% of women with lipoprotein metabolism have CAD by 50

Question 21

treatment of lipoprotein metabolism

Answer 21

statins (meds to lower cholesterol)
dietary restrictions
plasmapheresis (procedure to remove and replace blood plasma from the body)

Question 22

carbohydrate metabolism - galactosemia: what are the symptoms in new borns

Answer 22

vomiting
jaundice
food refusal
hepatomegaly (enlarged liver)
lethargy (fatigue)
edema

Question 23

treatment of galactosemia

Answer 23

avoiding lactose, fruit and veg

Question 24

newborn screening - rationale for screening

Answer 24

• it must be a disease that lots are screening for
• the test must be useful
• the disease must be easily identified
• parents must be able to give consent

Question 25

what are the pros and cons of having a low threshold for screening

Answer 25

miss no cases but there are many false positives

Question 26

what are the pros and cons of having a high threshold for screening

Answer 26

you miss cases but there are few false positives

Question 27

name some diseases that are currently screened for

Answer 27

PKU
Galactosaemia
maple syrup urine disease
cystic fibrosis
MCADD