Bones - Developmental Disorders

Question 1

What are 2 developmental disorders due to defects in Hormones and Signal Transduction Proteins?

Answer 1

1. Achondroplasia

2. Thanatophoric Dysplasia

Question 2

How is Achondroplasia inherited?

Answer 2

Autosomal Dominant

Question 3

What mutation causes Achondroplasia?

Answer 3

FGFR3 Gain of Function mutation

Question 4

What are the symptoms of Achondroplasia?

Answer 4

Dwarfism

- Short extremities, NORMAL trunk length, enlarged head

Question 5

With Achondroplasia, is there a change in the patient’s longevity, intellect or reproductive organs?

Answer 5

NO

Question 6

Achondroplasia is a form of dwarfism. What part of their body is of normal length?

Answer 6

Normal trunk length

Question 7

What mutation is present with Thanatophoric Dysplasia?

Answer 7

A different FGFR3 gain of function mutation than one that is present with Achondroplasia

Question 8

What disease is the more LETHAL form of Dwarfism?

Answer 8

Thanatophoric Dysplasia

Question 9

What dwarfism symptom can help to differentiate Thanatophoric Dysplasia?

Answer 9

Small chest cavity!

Question 10

With Thanatophoric Dysplasia, is there a change in the patient’s longevity?

Answer 10

Yes – die soon after birth

Question 11

What is 1 developmental disorder that is due to defects in Extracellular Proteins?

Answer 11

Osteogenesis Imperfecta

Question 12

What is deficient with Osteogenesis Imperfecta?

Answer 12

Deficient Type 1 Collagen Synthesis
– usually alpha 1 or alpha 2 chains

(COL1A1/2)

Question 13

What is deficient with Osteogenesis Imperfecta?

Answer 13

Deficient Type 1 Collagen Synthesis

Question 14

What are the signs of Osteogenesis Imperfecta?

Answer 14

Brittle bones
Blue sclera
Hearing loss
Dental imperfections

Question 15

What are the signs of Osteogenesis Imperfecta?

Answer 15

Brittle bones
Blue sclera
Dental imperfections
Hearing loss

Question 16

There are 4 subtypes of Osteogenesis Imperfecta. Some of which have mutant collagen and some have decreased normal collagen. Which is more severe?

Answer 16

Mutant collagen

Question 17

Rank the best -> worst prognosis of the types of Osteogenesis Imperfecta?

Answer 17

1
4
3
2

Question 18

Type 1 Osteogenesis Imperfecta life span and when fractures present?

Answer 18

NORMAL life span

– Fractures decrease in frequency AFTER puberty

Question 19

A patient presents with a wedge shaped face, loose joints and normal stature. What type of Osteogenesis Imperfecta do they have?

Answer 19

Type 1

Question 20

Type 2 Osteogenesis Imperfecta involves what not being formed?

Answer 20

Triple helix formation does NOT happen

Question 21

Type 2 Osteogenesis Imperfecta has what type of outlook?

Answer 21

FATAL in utero usually

Question 22

A fetus has respiratory problems, severe bone deformities and a small stature. They ultimately die in utero. What type of Osteogenesis Imperfecta did they have?

Answer 22

Type 2

Question 23

What is the treatment for Osteogenesis Imperfecta?

Answer 23

Surgical rodding of long bones

Question 24

Fractures that occur in child abuse are similar to those seen with Osteogenesis Imperfecta. What types of fractures?

Answer 24

Spiral
Rib
Fractures in multiple stages of healing with no signs of trauma

Question 25

What is 1 developmental disorder that is due to defects in Metabolic Pathways?

Answer 25

Osteopetrosis

Question 26

What is deficient with Osteopetrosis?

Answer 26

Deficient Osteoclasts | = Decreased bone resorption

Question 27

What is deficient with Osteopetrosis?

Answer 27

Deficient Osteoclasts | = Decreased bone resorption

Question 28

Albers-Schonberg Disease is the Autosomal Dominant form of Osteopetrosis. What is its mutation and symptom severity?

Answer 28

MILD symptoms | -- CLCN7 mutation

Question 29

The Autosomal Recessive forms of Osteopetrosis involve what possible mutations are symptom severity?

Answer 29

SEVERE symptoms - - TCIRG1 mutations - - Carbonic Anhydrase 2 mutations

Question 30

With Osteopetrosis, what changes are present with bones?

Answer 30

``` LACK medullary cavity Bulbous ends (look like erlenmeyer flasks) ```

Question 31

With Osteopetrosis, cranial nerves can be compressed due to deficient osteoclasts. What are some symptoms?

Answer 31

Deafness Optic atrophy Facial paralysis

Question 32

Besides the cranial nerve symptoms, what are the other symptoms seen with Osteopetrosis?

Answer 32

Fractures Anemia Leukopenia and infections

Question 33

With what disease do bones lack medullary cavities and have bulbous ends?

Answer 33

Osteopetrosis

Question 34

What is a group of developmental disorders due to defects in degradation of macromolcules?

Answer 34

Mucopolysaccharidoses - lysosomal storage diseases

Question 35

Where do Mucopolysaccharides accumulate?

Answer 35

In Chondrocytes and extracellular space