Ch. 20 - Congenital bone/cartilage diseases

Question 1

Musculoskeletal system (MSK) is also known as what?

Answer 1

The locomotor system

Question 2

Tissues involved in the musculoskeletal system?

Answer 2

osseous, muscular, connective

Question 3

The musculoskeletal system integrates with what other system?

Answer 3

The nervous system

Question 4

Congenital disorders?

Answer 4

Dystosis 
Dysplasia
osteogenesis imperfect (O.I.)
achondroplasia
osteopetrosis

Question 5

What is dysostosis?

Answer 5

Developmental anomaly of bone

Question 6

Dysostosis includes what features?

Answer 6

Abnormal mesenchymal migration

Defective ossification of fetal cartilage

Question 7

Dysostosis can either be ______ or part of a _____?

Answer 7

Sporadic (isolated)

syndromes

Question 8

Dysostosis contains what kind of gene alterations?

Answer 8

homeobox gene alterations

Question 9

The homeobox gene deals with what?

Answer 9

Structural development during embryologic development

Question 10

This condition shows: 1) aplasia, 2) supernumary digits, and 3) abnormal fusion of bones.

Answer 10

dysostosis

Question 11

Mutations that interfere with growth or homeostasis (dwarfism). (condition)

Answer 11

dysplasia

Question 12

Dysplasia in bone called:

Answer 12

osteodysplasia

Question 13

Dysplasia in cartilage called:

Answer 13

chondrodysplasia

Question 14

Dysplasia in this context is ____ pre-cancerous?

Answer 14

NOT

Question 15

A type of dysostosis that shows Sprengel’s Deformity, is idiopathic, and has congenital fusion of any 2 cervical vertebrae

Answer 15

Klippel -Feil syndrome

Question 16

What is the MC congenital malformation of the limbs?

Answer 16

syndactyly

Question 17

What is the ratio of live births showing syndactyly?

Answer 17

1:2000-3000 live births

Question 18

Two features of digits that show up in dysostosis?

Answer 18

Syndactyly and

polydactyly

Question 19

Osteogenesis imperfect (O.I.) is also known as what?

Answer 19

Brittle bone disease

Question 20

O.I. has mutations of what?

Answer 20

Type 1 collagen (alpha1 or alpha2 chains)

Question 21

The type of mutations in O.I. of collagen type 1 is _____ dominant.

Answer 21

autosomal dominant

Question 22

Abnormal collagen in O.I. leads to what?

Answer 22

Premature breakdown

Question 23

Abnormal extracellular matrix in O.I. affects what areas?

Answer 23

Eyes, inner ear bones, skin, joins, teeth

Question 24

Type I O.I. life expectancy

Answer 24

Normal lifespan

Question 25

Type II O.I. life expectancy

Answer 25

Lethal in uteral

Question 26

Type II O.I. causes what to happen in utero?

Answer 26

Cerebral hemorrhage, | Respiratory failure.

Question 27

When is type I O.I. diagnosed?

Answer 27

In childhood

Question 28

What are common things associated with type 1 O.I.

Answer 28

Fractures, extremity bowing, scoliosis, ligamentous laxity (dislocations), hearing loss, short stature

Question 29

Children with O.I. who have been treated with biophosphates (cyclical) show what sign on radiography?

Answer 29

Zebra stripe sign

Question 30

What is the MC form of dwarfism?

Answer 30

Achondroplasia

Question 31

How does achondroplasia lead to dwarfism?

Answer 31

Decreased cartilage synthesis leads to deceased growth plate expansion.

Question 32

What inhibits the epiphyseal (growth plate) chondrocytes?

Answer 32

FGFR3 (Fibroblast growth factor receptor) mutation

Question 33

What is the percentage of spontaneous achondroplasia?

Answer 33

75%

Question 34

What is the percentage of autosomal dominant achondroplasia?

Answer 34

25%

Question 35

What are some feature of those with achondroplasia?

Answer 35

Short proximal extremities, lower extremity bowing, frontal bossing, mid-face hypoplasia (low nasal bridging)

Question 36

The lollipop kids on "The WIzard of Oz" are which kind of dwarfism?

Answer 36

hypopituitary dwarfism

Question 37

What are some other causes of dwarfism?

Answer 37

Turner syndrome Hypothyroidism Malnutrition O.I.

Question 38

What is the incidence of achondroplasia?

Answer 38

1:10,000

Question 39

What are some features of the spinal column in achondroplasia?

Answer 39

hyperlordosis and kyphosis at birth Bullet vertebrae Scoliosis Spinal stenosis

Question 40

What other types of stenosis can occur in achondroplasia?

Answer 40

foramen magnum stenosis | Spinal canal stenosis

Question 41

What can cause death in achondroplasia?

Answer 41

Brain stem compression

Question 42

What else can be lethal with achondroplasia?

Answer 42

Cardiovascular abnormalities

Question 43

What is the fatal type of dwarfism?

Answer 43

thanatophoric dwarfism

Question 44

What is the incidence of thanatophoric dwarfism?

Answer 44

1 : 20,000 births

Question 45

What happens in thanatophoric dwarfism?

Answer 45

Extremely small thorax and shortened long bones that lead to perinatal respiratory failure.

Question 46

What is osteopetrosis?

Answer 46

A group of rare genetic disorders that decrease osteoclast-mediated bone reabsorption.

Question 47

Osteopetrosis creates what?

Answer 47

Skeletal sclerosis or "stone-like" bone

Question 48

Skeletal sclerosis in osteopetrosis can lead to what?

Answer 48

Increased fractures.

Question 49

Besides increase fractures what other things happen with osteopetrosis?

Answer 49

formainal stenosis --> cranial nerve palsied | medullary cavity fills --> deranged hematopoies

Question 50

In osteopetrosis, when the medullary cavity fills it also can lead to what?

Answer 50

``` hepatosplenomegaly Recurrent infections (anemia) ```

Question 51

What is the treatment for osteopetrosis?

Answer 51

Stem cell replacement

Question 52

What are some features on x-ray of osteopetrosis?

Answer 52

White bone because of no medulla and | Erlenmeyer flask deformity