Cellular & Molecular Basis of Disease

Question 1

Enzyme defect pathology

Answer 1

Causes either an accumulation of the substrate or a deficiency of the product

Question 2

PKU

Answer 2

Autosomal recessive
Mutation in phenylalanine hydrogenase
Normal; convert Phe to Tyr
Without enzyme, buildup of Phe in tissue can lead to mental retardation

Question 3

Tay-Sachs

Answer 3

Autosomal recessive
Most common lysosomal storage disorder
Mutation in gene for alpha subunit of hexosaminidase A
10x more common in Cajuns than in the general population

Question 4

Albinism

Answer 4

Tyrosinase deficiency
Tyrosine–>DOPA–>melanin
Lack of fovea development

Question 5

G6PD deficiency

Answer 5

Most common human enzyme deficiency
More common in AA male
Results in hemolytic anemia in states of oxidative stress
Heinz bodies–advantageous against malaria

Question 6

Familial hypercholesterolemia

Answer 6

Autosomal dominant
Mutated gene for LDL receptor
Xanthomas, coronary artery disease

Question 7

Cystic fibrosis

Answer 7

Frameshift mutation in chloride ion channel

Carriers may have been more resistant to cholera

Question 8

Duchenne muscular dystrophy

Answer 8

100x increase in creatine kinase
X-linked recessive inheritance
Largest gene ever

Question 9

Osteogenesis Imperfecta

Answer 9

Defect in Type I collagen
Brittle bone disease
Blue sclera

Question 10

Thalassemia

Answer 10

Mutations in either alpha or beta globin gene

Question 11

Trinucleotide repeat disorders

Answer 11

Friedrich’s ataxia
Fragile X
Myotony dystrophy
Huntington’s