Skeletal Dysplasia

Question 1

When should we suspect skeletal dysplasia?

Answer 1

disproportion, joint abn (limitation of motion), bone deformity (bowing, thumb deficiency), others

Question 2

dysplasia is:

Answer 2

bad growth caused by intrinsic bone abn

Question 3

dysostosis is:

Answer 3

deformity or maldevelopment of a single bone or body segment

Question 4

dystrophy is:

Answer 4

deformities caused by metabolic or nutritional problems

Question 5

chondrodystrophy is:

Answer 5

disturbance that includes various systems including bone

Question 6

chondrodysplasia:

Answer 6

generalized disturbance of bone modeling

Question 7

how are bone disorders classified?

Answer 7

anatomically, clinical features, radiographically, molecular/pathogenic

Question 8

When is bone remodeling occuring?

Answer 8

throughout life, most significant in 1st year

Question 9

Which bone ossifies first?

Answer 9

clavicle

Question 10

which group of bones ossify over time and are often used for bone age? first and last?

Answer 10

wrist

capitate (1st year)

pisiform (10th year)

Question 11

what is the most common type of dwarfism?

Answer 11

achondroplasia

Question 12

the disproportionate short stature is characterized by:

Answer 12

discrepancies in limb and trunk length

Question 13

what gene is associated with achondroplasia?

Answer 13

FGFR3

Question 14

what are some radiological findings of achondroplasia?

Answer 14

narrowing of the space in lumbar spine

short vertebral bodies

square iliac wings

radiolucency of the proximal femora (ends of bones don’t show up as well on X-ray)

Question 15

when is bone foreshortening typically seen on U/S

Answer 15

20-24wks

Question 16

what are the molecular genetics of achondroplasia?

Answer 16

AD pattern
>80% de novor ate
correlated with advanced paternal age
100% penetrance

Question 17

rhizomelic shows:

Answer 17

short proximal segments (humerus, femur)

Question 18

mesomelic shows:

Answer 18

short middle segments (radius, ulna, tibia, fibula)

Question 19

acrocentric limbs shows:

Answer 19

short distal segments (digits)

Question 20

what type of OI is most severe? characteristics?

Answer 20

type 2

prenatal fractures, poor bone mineralization, multiple healing fractures

Question 21

What genes are associated with OI?

Answer 21

COL1A1 and COL1A2

Question 22

what is the recurrence risk associated with OI if more than one affected child has been born to unaffected parents?

Answer 22

28%

Question 23

osteoporosis, achondrogenesis, Ellis-van Creveld syndrome, Rhizomelic chondrodysplasia, disatrophic dysplasia, and others are all examples of disorders with:

Answer 23

increased bone density