Biochemistry Autosomal Dominant Disorders

Question 1

What is the etiology behind Achondroplasia?

Answer 1

Mutation in FGFR3 makes it active and inhibits chondrocyte proliferation

Question 2

Clinical presentation of Achondroplasia

Answer 2

Dwarf, short limbs of long bones, normal torso, slightly large head but usually normal

Question 3

What are the two mutation in autosomal dominant polycystic kidney disease?

Answer 3

PKD1 mutation on Chromosome 16 (85%)

PKD2 mutation on Chromosome 4 (15%)

Question 4

What is the mutation in Familial adenomatous polyposis?

Answer 4

Mutation of APC gene on 5q

Question 5

What is the mutation in Familial hypercholesteremia

Answer 5

Defective or absent LDL receptor

Question 6

Clinical presentation of Familial hypercholesterolemia

Answer 6

Rapid onset severe atherosclerotic disease, corneal arcus, tendon xanthomas

Question 7

What is the other name of Hereditary hemorrhagic telengiectasia

Answer 7

Osler-Weber-Rendu syndrome

Question 8

Clinical findings of Osler-Weber-Rendu syndrome?

Answer 8

Telengiectasias, recurrent epistaxis (nosebleeds), skin discolorations, AVMs, GI bleeding, hematuria

Question 9

What defect leads to hereditary spherocytosis?

Answer 9

Spectrin or ankyrin defect. Leads to hemolytic anemia

Question 10

What is the defect in Li-Fraumeni syndrome?

Answer 10

Defective TP53

Question 11

Clinical manifestations of Li-Fraumeni syndrome

Answer 11

Sarcoma, breast, leukemia and adrenal gland cancers

Question 12

Which gene is mutated in Marfan syndrome?

Answer 12

Fibrillin (FBN1) on chromosome 15 (FIbrillin, FIfteen)

Question 13

Clinical manifestation of Marfan syndrome

Answer 13

Connective tissue disorder that affects skeleton, heart and eyes. Tall with long fingers, joints and extremities. Medial necrosis of aorta, aortic insufficiency, risk of dissection, floppy mitral valve. Dislocated lenses

Question 14

What are the chromosome mutations for NF-1 and NF-2, respectively?

Answer 14

17 and 22