Glycogen storage diseases

Question 1

What are glycogen storage disease?

Answer 1

inherited disorders that affect glycogen metabolism

Question 2

What areas in the body affected by glycogen storage disease?

Answer 2

liver and skeletal muscle

Question 3

What do the disorders that affect the liver result in?

Answer 3

Hepatomegaly - enlarged liver

Hypoglycaemia - low blood sugar levels

Question 4

What do the disorders that affect the muscle cause?

Answer 4

muscle cramps and weakness

Question 5

What can glycogen storage disease also cause disturbances on?

Answer 5

Renal and CV

Question 6

What is type 1 glyocogen disease?

Answer 6

Glucose-6-phosphatase defiency, von gierkes diseases

Question 7

What does glucose-6-phosphatase do?

Answer 7

Catalyses the release of phosphate group allows free glucose to be released from the liver into the bloodstream

Question 8

What does a defiency in glucose-6-phosphatase result in?

Answer 8

Large increase in intra-cellular G-6-P

Question 9

What does type 1 defiency cause?

Answer 9

large accumulation of glycogen in the liver and kidney and inability to increase blood sugar levels in response to glucagon and adrenaline release

Question 10

What are symptons of von gierkes disease?

Answer 10

Severe hepatomegaly and severe hypoglycaemia

Question 11

What are the treatments for von gierkes disease?

Answer 11

treat hypoglycaemia of drug induced inhibition and continous intra-gastric feeding overnight
liver transplant

Question 12

What is the surgical option for von gierkes disease?

Answer 12

surgical transposition of the portal vein - portal vein delivers glucose rich blood from the intestines to the liver - diverts glucose to peripheral tissues first

Question 13

What is type 2 disease?

Answer 13

Pompes disease a-1,4 glucosidase defiency

Question 14

What happens with type 2 disease?

Answer 14

most severe - die of cardio-resp failure before 1yr

Question 15

What is enzyme a-1,4 glucosidase in involved in ?

Answer 15

gylcogen degradation in lysosomes - glycogen granules taken up by lysosomes and broken down

Question 16

What does type 2 causes?

Answer 16

Accumulation of glycogen in lysosomes of all cells - disrupts lysosomal functions

Question 17

how can type 2 disease detected by?

Answer 17

blood tests for mutations 1/85 people carry recessive trait

Question 18

What does mutations cause?

Answer 18

destroy protein - infant onset pompes disease

mutations that leave enzyme intact adult/juve disease

Question 19

What is treatment for type 2 disease?

Answer 19

without a-1-4 glucosidase glycogen builds up inside lysosome and ruptures damaging muscle tissue
GAA or enzyme replacement therapy

Question 20

what is type 3 disease?

Answer 20

Coris disease - amylo1,6,glucosidase, debranching enzyme

Question 21

What happens in type 3 disease?

Answer 21

Glycogen formed has abnormal structure and buils up - short outer chain accumulates in liver and muscle

Question 22

What happens in type 3?

Answer 22

Absence of debranching enzyme - gylcogen cant be completely degraded, symptons appear in puberty

Question 23

What are symptons of type 3 coris disease?

Answer 23

muscle weakness and liver problems, similiar to type 1 - not as sever hypoglycaemia

Question 24

How do treat type 3 disease?

Answer 24

frequent feeding and high protein diet

Question 25

What is type IV - 4 andersons disease?

Answer 25

deficiency of glycogen branching enzyme, amylo-transglycosylase

Question 26

What does type IV do?

Answer 26

adds new branches in glycogen molecule during synthesis - results in reduced ability to store glucose residues as glycogen

Question 27

What is severity of type IV 4?

Answer 27

one of most sever - rarely survive past age 4 - long unbranched chains make it very insoluve

Question 28

What is main sympton of andersons disease?

Answer 28

liver dysfunction - immune response to abnormal glycogen

Question 29

What is type V - 5 mcardles disease?

Answer 29

Muscle phosphorylase defiency

Question 30

What happens in type V - 5?

Answer 30

glucose residues are removed from glycogen as G1-P by glycogen phosphorylase

Question 31

What is affected in type 5?

Answer 31

glycogen breakdown in muscle affected leads to lack of glucose for glycolysis to produce ATP

Question 32

What are symptons of type 5?

Answer 32

painful muscle cramps after exertion - muscle cant convert glycogen to glucose to lactate - muscle tissue breaksdown due to lack lactate

Question 33

What is treatment of type V -5 ?

Answer 33

disease not fatal, quite harmless as long as strenuous exercise is avoided

Question 34

What is type VI - 6 disease?

Answer 34

Liver phosphorlase defiency - Her's disease

Question 35

What happens in VI - 6 disease?

Answer 35

similiar to type 1, lack of glycogen phosphorylase in the liver - mild symptons

Question 36

What are symptons of hers type 6 disease?

Answer 36

enlarged liver with mild hypoglycaemia - mild ketosis and retarded growth

Question 37

Why does hypoglycaemia results from and ketosis?

Answer 37

Hypoglycaemia - inability to breakdown liver glycogen to increase blood glucose levels Ketosis - non functioning TCA cycle

Question 38

What is type VII disease? 7

Answer 38

muscle phosphofructokinase defiency taruis disease

Question 39

What happens in type 7 disease?

Answer 39

defiency of phosphofuctokinase in muscle disrupts glycolysis - leads to build up of glucose-6,fructose,6 phosphate

Question 40

What happens in type 7 disease?

Answer 40

high conc of glucose -6-phosphate increases the activity of glycogen synthase and UDP-glucose pyrophosphorylase

Question 41

What does type 7 cause?

Answer 41

Build up of glycogen in the muscle - painful muscle cramps

Question 42

What is type VIII - 8 ?

Answer 42

X-linked phosphorylase kinase defiency

Question 43

What happens in type 8 disease?

Answer 43

defective phosphorylase kinase cant add phosphate to convert glycogen to phos b to active phos a

Question 44

Why is glycogen not broken down?

Answer 44

lack of phosphorylated active form of glycogen phosphorylase - similiar symptons to type 6, this is x-linked

Question 45

What is type XI? 9 ?

Answer 45

phosphorylase kinase defiency

Question 46

What does type 9 disease cause?

Answer 46

autosomal recessive disease - from mutations in genes that encode phosphorylase kinase subunits

Question 47

What is symptons of type 9?

Answer 47

different tisses have different isoenzymes of phosphorylase kinase - depends on affected organ

Question 48

What is type 0 disease?

Answer 48

Liver glycogen synthase defiency

Question 49

What does type 0 disease cause?

Answer 49

only glycogen with too little glycogen - glycogen synthase activity is low and suffer from hypoglycaemia after meals