Collagen

Question 1

Name the 4 types of loct of different collagens

Answer 1

Type1–Bones (90% total coolagen in body)-decf in osteogenesis imperfecta type 1.
Type2–Cartilage
Type3–BV (defc in Ehnler Danlos syndrome)
Type4–BM

Question 2

Collagen function

Answer 2

Gives structure and strength to ECM

Question 3

Most abundant protei in our body?

Answer 3

COLLAGEN

Question 4

Gly-X-Y?

Answer 4

X-Lysine or Proline
Y-HydroxyLysine or HydroxyProline
-Gly-Glycine is 1/3 of collagen and varies the less

Question 5

Collagen synthesis and relating there disease..

Answer 5

1.Prepo-collagen (Gly-X-Y)
2.Hydroxylation of X, requieres vit c. (Scurvy arises)
3.glycosylation of pro-α chain of hydroxy-lysine residues and formation of procollagen via *hydrogen and disulfide bonds (triple helix of 3 collagen αchains)–>Faliure of formation of triple helix= osteogenesis imperfecta.
4.exocytosis of procollagen into extracellular space.
5.Proteolytic processing— cleavage of disulfide-rich terminal regions of pro-collagen–> insoluble tropocollagen.
6.Assembly and alignment—collagen assembles in fibrils and aligns for cross-linking.
7.Cross-linking—reinforcement of staggered tropocollagen molecules by covalent lysine-hydroxylysine cross-linkage to make collagen fibrils.Cross-linking of collagen increases with age.Problems with cross-linking–> Menkesdisease

Question 6

Other name for vit C

Answer 6

ascorbic acid

Question 7

swollen gums,easy bruising,petechiae,hemarthrosis,anemia,poor wound healing,perifollicula and subperiosteal hemorrhages,“corkscrew”hair, Weakened immune response.

Answer 7

SCURVY
-precipitated by tea and toast diet.

Question 8

What vitamine?

1.Antioxidant;also facilitates iron absorption by reducing it toFe2+state.
2.Necessary for hydroxylation of proline and lysine in collagen synthesis.
3.Necessary for dopamineβ-hydroxylase(converts dopamine to NE).

Answer 8

ascorbic acid

Question 9

-brittle, “kinky”hair ,growth and developmental delay, hypotonia, risk of cerebral aneurysms.
-impaired copper absorption and transport due to defective protein ATP7A(Absent copper)
-X-linked recessive connective tissue disease.

Answer 9

Menkes disease

Question 10

Diagnosis

decrease activity of lysyl oxidase

Answer 10

Menke disease
-decr activity of **collagen cross linking. **

Question 11

ATPB7 vs ATPA7

Answer 11

ATPB7=Wilson dis.(excessive Copper absp)

Question 12

-hyperextensible skin,hypermobile joints,and tendency to bleed(easybruising).
-ASS. with joint dislocation ,berry and aortic aneurysms,organ rupture.
-Diff types

Answer 12

Ehnler Danlos syndrome
-defective collagen synthesis.

Question 13

-COL1A1 and COL1A2 gene mutation
-autosomal dominant with production of otherwise normal type I collagen (altered triple helix formation).

Answer 13

Osteogenesis imperfecta

Question 14

-Multiple fractures and bone deformities after minimal trauma (birth)
-Blue sclera due to the translucent connective tissue ove rchoroidal veins
-Conductive hearing loss(abnormal ossicles)

Answer 14

Osteogenesis Imperfecta

Question 15

Answer 15

Blue sclerae (Osteogenesis Imperfecta)

Question 16

What is confused with osteogenesis imperfecta?

Answer 16

Child Abuse

Question 17

What to we treat osteogenesis imperfecta?

Answer 17

Biphosphonate
-Pyrophosphate analogs; bind hydroxy-apatite in bone,inhibiting osteoclast activity.

Question 18

Treatment

Osteoporosis,hypercalcemia,Paget disease of bone,metastatic bone disease,osteogenesis imperfecta.

Answer 18

Biphosphonate