Inherited metabolic disorders

Question 1

Name the 4 types of glycogen storage disease

Answer 1

Von Gierke’s disease (type I)
Pompe’s disease (type II)
Cori disease (type III)
McArdle’s disease (type V)

Question 2

Glucose-6-phosphatase deficiency
Hepatic glycogen accumulation.

Key features include hypoglycaemia, lactic acidosis, hepatomegaly

Answer 2

Von Gierke’s disease (type I)

Question 3

Lysosomal alpha-1,4-glucosidase deficiency
Cardiac, hepatic and muscle glycogen accumulation.

Key features include cardiomegaly

Answer 3

Pompe’s disease (type II)

Question 4

Alpha-1,6-glucosidase (debranching enzyme) deficiency Hepatic, cardiac glycogen accumulation.

Key features include muscle hypotonia

Answer 4

Cori disease (type III)

Question 5

Glycogen phosphorylase (myophosphorylase) deficiency
Skeletal muscle glycogen accumulation.

Key features include myalgia, myoglobinuria with exercise

Answer 5

McArdle’s disease (type V)

Question 6

Give examples of Lysosomal storage disease

Answer 6

Gaucher’s disease
Tay-Sachs disease
Niemann-Pick disease
Fabry disease
Krabbe’s disease
Metachromatic leukodystrophy

Question 7

Beta-glucocerebrosidase defect
Most common lipid storage disorder resulting in accumulation of glucocerebrosidase in the brain, liver and spleen.

Key features include hepatosplenomegaly, aseptic necrosis of the femur

Answer 7

Gaucher’s disease

Question 8

Hexosaminidase A defect
Accumulation of GM2 ganglioside within lysosomes.

Key features include developmental delay, cherry red spot on the macula, liver and spleen normal size

Answer 8

Tay-Sachs

Question 8

Sphingomyelinase defect

Key features include hepatosplenomegaly, cherry red spot on the macula

Answer 8

Niemann-Pick disease

Question 9

Alpha-galactosidase-A defect
Accumulation of ceramide trihexoside.

Key features include angiokeratomas, peripheral neuropathy of extemeties, renal failure

Answer 9

Fabry disease

Question 10

Galactocerebrosidase defect

Key features include peripheral neuropathy, optic atrophy, globoid cells

Answer 10

Krabbe’s disease

Question 11

Arylsulfatase A defect
Demyelination of the central and peripheral nervous system

Answer 11

Metachromatic leukodystrophy

Question 12

Mucopolysaccharidoses

Answer 12

Hurler Syndrome (Type 1)
Hunter Syndrome (type 2)

Question 13

Alpha-1-iduronidase defect
Accumulation of glycosaminoglycans (heparan and dermatan sulfate).

Key features include gargoylism, hepatosplenomegaly, corneal clouding

Answer 13

hurler Syndrome (Type 1)

Question 14

Iduronate sulfatase defect
Accumulation of glycosaminoglycans (heparan and dermatan sulfate).

Key features include coarse facial features, behavioural problems/learning difficulties short stature, no corneal clouding

Answer 14

Hunter Syndrome (Type 2)