Step 1 Biochem

Question 1

Fabry

Answer 1

Deficiency: alpha galactosidase A
Build up: ceramide trihexoside
Inheritance: x linked recessive

neuropathy
angiokeratomas
renal failure
CV disease

Question 2

Metachromatic Leukodystrophy

Answer 2

Deficiency: Arylsulfatase A
Build up: cerebroside
Inheritance: autosomal recessive

central and peripheral demylination
ataxia
dementia

Question 3

Krabbe Disease

Answer 3

Deficiency: galactocerebrosidase
Build up: galactocerebroside, psychosine
Inheritence: autosomal recessive

neuropahty
oligodendrocyte destruction
globoid cells
developmental delay
optic atrophy

Question 4

Gaucher

Answer 4

Deficiency: glucocerebrosidase
Build up: glucocerebroside
Inheritence: autosomal recessive

Tx: recombinate glucocerebrosidase
gaucher- crumbled paper cells, lipid laden macrophages
hepatosplenomegaly
pancytopenia
osteoporosis
avascular necrosis of femur
bone crisis

Question 5

Tay-Sachs Disease

Answer 5

tAy saX disease

Deficiency: hexosamindase A
Build up: GM2 ganglioside
Inheritance: autosomal recessive

neurodegeneration
“cherry red” spot macula
lysosomes w/ onion skin
no hepatosplenomegaly

Question 6

Niemann-Pick Disease

Answer 6

Deficiency: sphingomyelinase
Build up: sphingomyelin
Inheritance: autosomal recessive

“cherry red” macula
foam cells- macrophage with lipid
hepatosplenomegaly

Question 7

Huler Syndrome

Answer 7

Deficiency: alpha-L-iduronidase
Build up: heparin sulfate, dermatin sulfate
Inheritence: auto recessive

developmental delay
corneal clouding
hepatosplenomegaly

Question 8

Hunter Syndrome

Answer 8

Deficiency: idurona/te-2(two)-sulfaTase
build up: heparin sulfate, dermatin sulfate
Inheritance: X linked recessive

milder huler
no corneal deposits
aggressive behavior
developmental delay
hepatosplenomegaly

Question 9

I cell disease

Answer 9

Deficiency: N-acetylglucosaminyl-1-phosphotransferase
decrease mannose-6-phosphage
Build up: cellular debris
Inheritance: AR

golgi apparatus cannot phosphorylate mannose residue
inclusion bodies

Question 10

Von Gierke

Answer 10

1st glycogen storage disorder
Deficient: glucose-6-phosphtase

increase:
glycogen in liver in kidney
lactase
triglyceridse
uric acid-gout
hepatomegaly

tx: increase oral glucose/corn starch
decrease fructose and galactose

Question 11

Pompe

Answer 11

2nd glycogen storage disorder
Deficient: alpha 1,4 glucosidase

cardiomegaly
enlarge tongue
exercise intolerance
hypotonia
early death

Question 12

Cori

Answer 12

3rd glycogen storage disorder
Deficient: alpha 1,6 glucosidase and 4-alpha-D-glucotransferase

ABCD- cori is debranching deficiency

similar to Von Gierke
but normal lactase
limit dextrin like structure in cytosol
muscle involvement

Question 13

Anderson

Answer 13

4th Glycogen storage disorder
Deficient: Branching enzymes (ABCD)

hepatosplenomegaly
failure to thrive
neuromuscular disorder in adults
cardiomegaly
muscular weakness
infantile cirrhosis

Question 14

McArdle

Answer 14

5th glycogen storage disorder
Deficient: muscle glycogen phosphorylase, AKA myophosphorylase

flat venous lactase curve with normal ammonia rise during exercise
blood glucose not affected
muscle cramps
2nd wind

Question 15

Essential Fructosuria

Answer 15

Deficient: fructoKinase (kinder)
fructose in blood in urine
typically asymptomatic

Question 16

Hereditary B Deficiency

Answer 16

Deficient: Aldose B

Tx: decrease fructose intake, decrease sucrose and sorbitol

Becomes symptomatic when weaning off breast feeding

Question 17

Galactokinase Deficiency

Answer 17

infantile cataracts
galactose in blood and urine
less severe

Question 18

Classic Galactosemia

Answer 18

Deficient: galactose-1-phosphate uridyltransferase

breast feeding
infantile cataracts
failure to thrive
intellectual disability
jaundice
hepatomegaly
predispose to E coli