Hereditary Bone Conditions

Question 1

What is the most common form of Dwarfism?

Answer 1

Achondroplasia

Question 2

What is the most common disorder of growth plates of the appendicular skeleton?

Answer 2

Achondroplasia

Question 3

What gene is associated with decreased chondrocyte replications the growth plate in the most common type of dwarfism?

Answer 3

Autosomal dominant
(Fibroblast Growth Factor Receptor 3 (FGFR3))

Question 4

What physical attributes do you expect to see in patients with Achondroplasia?

Answer 4

• Normal sized torso, but shortened limbs (Rhizomelic appearance)
• head>face
• depressed nasal ridge
• thoracic hyperkyphosis
• lumbar hyperlordosis

Question 5

Do individuals with achondroplasia have a normal life expectancy?

Answer 5

Yes

Question 6

What radiographic characteristics do you expect to see in patients with Achondroplasia?

Answer 6

• bullet vertebrae
• post. vertebral scalloping
• congenital central stenosis
• Hyperlordosis w/ horizontal sacrum when skeletally mature
• Short broad metaphysis
• Champagne glass appearance
• flat ilia (paddle-shaped)

Question 7

Stenosis of the vertebral foramen is a major concern in what conditions?

Answer 7

Achondroplasia

Question 8

What collagen synthesis disorder has an increased chance of developing mitral valve prolapse and dissecting aneurysms?

Answer 8

Marfan’s Syndrome

Question 9

What gene mutation is commonly associated with Marfan’s Syndrome?

Answer 9

Autosomal dominant (FBN1 gene)

Question 10

What are some of the clinical characteristics of patients with Marfan’s Syndrome?

Answer 10

• M>F
• Tall, slender individuals (long extremities)
• Arachnodactyly
• Hypermobile joints
• Scoliosis
• pectus excavatum (sternum in)
• pectus carinatum (sternum out)

Question 11

What are some radiographic findings you would see with patients with Marfan’s syndrome?

Answer 11

• scoliosis
• elongated extremities (arachnodactyly)
• thin, gracile bones
• thin cortices
• delicate trabecular pattern

Question 12

What inherited collagen synthesis disorder is also known as Brittle Bone disease?

Answer 12

Osteogenesis imperfecta

Question 13

What type of OI is considered the most fatal and characterized by developmental defects including extremely brittle bones?

Answer 13

Osteogenesis Imperfecta Congenital

Question 14

What type of OI is characterized by the anterior bowing of the extremities, the sclera of the eyes turning blue, and hearing loss due to bony deformities?

Answer 14

Osteogenesis Imperfecta Tarda

Question 15

What conditions is characterized by the hypofunctioning of osteoclasts and is called Marble Bone Disease?

Answer 15

Osteopetrosis

Question 16

What radiographic finding would you expect to see in patients with Osteopetrosis?

Answer 16

• Widening of metaphysis (“Erlenmeyer Flask” appearance)
• Lack of defined medullary cavity (radiopaque bone appearance)
• Sandwich vertebrae

Question 17

What would you expect PTH levels to be in patients with Osteopetrosis?

Answer 17

Elevated (boobs)

Question 18

In a normal, healthy individual, PTH will have what effect in the kidney?

Answer 18

Increase production of calcitriol

Question 19

What is the heredity of cleidocranial dysplasia?

Answer 19

Autosomal dominant

Question 20

Etiology of cleidocranial dysplasia

Answer 20

Mutation of gene that helps encode osteoblasts

Question 21

Cleidocranial dysplasia results in deficiency of ____ ossification, affecting what bones?

Answer 21

Intramembranous
Flat bones (skull, clavicles)

Question 22

What are the clinical features of cleidocranial dysplasia?

Answer 22

• large head, small face
• hypermobile shoulders (scapulothoracic)
• reduced height
• narrow, cone-shaped thorax
• hearing loss
• normal life span

Question 23

What are the radiographic features of cleidocranial dysplasia?

Answer 23

• absent/hypoplastic clavicles
• pseudoarthrosis (mid portion missing)
• small, winged, elevated scapulae
• narrow, cone-shaped chest

Question 24

What tool is used to assess hypermobility?

Answer 24

Beighton Questionnaire

Question 25

Osteogenesis imperfecta has ____ genotypes, and ____ phenotypes

Answer 25

4
2

Question 26

Osteogenesis imperfecta is a defect in…

Answer 26

Type I collagen synthesis

Question 27

What are the clinical manifestations of osteogenesis imperfecta tarda?

Answer 27

• congenital osteoporosis
• blue sclera
• conductive hearing loss
• severe dental problems

Question 28

What are the radiographic findings of osteogenesis imperfecta?

Answer 28

• mild to severe generalized osteopenia
• multiple fractures in various stages of healing

Question 29

What is the heredity of osteopetrosis?

Answer 29

2 forms:
- autosomal dominant
- autosomal recessive

Question 30

What are the clinical features of osteopetrosis?

Answer 30

• possible growth disturbances
• facial palsies (facial n compressed)
• neurogenic hearing loss (CN VIII compressed)
• dental caries

Question 31

What are the possible complications of osteopetrosis?

Answer 31

• pathologic Fx
• anemia
• thrombocytopenia
• hepatosplenomegaly
• blindness/deafness/facial n palsies
• leukaemia & sarcomas