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Flashcards in Skeletal dysplasia Deck (19):
1

Most common form of short-limbed dwarfism

Achondroplasia

2

Inheritance of achondroplasia?

Autosomal dominant, 80% new mutations

3

Most consistent sonographic finding in achondroplasia?

Short long bones, esp femur, btw 21-27w (<3rd percentile) - but important finding is initially normal 1st & 2nd trimester measurements

4

Other sonographic features of achondroplasia

Normal shape of femur
Macrocrania
Frontal bossing
Protuberant abdomen
Trident-shaped hand
Polyhydramnios

5

What is diastropic dysplasia?

A recessively inherited form of short-limbed dwarfism, with the additional findings of thickening of the external ear and the characteristic "hitch-hiker" thumbs.

6

What is achondrogenesis?

A lethal, recessively inherited condition, there is deficient ossification of the vertebral bodies. As compared with achondroplasia, a greater discrepancy between head size and trunk exists in achondrogenesis.

7

What is Ellis-van Creveld syndrome?

Chondroectodermal dysplasia
Progressive distal shortening of the extremities and postaxial polydactyly are present
Congenital heart malformations are present in 50% of cases.

8

What is hypochrondroplasia?

The major findings are short stature and an increased upper-to-lower body segment ratio. The facial features are within normal limits.

9

What is the gene mutation in achondroplasia?

FGFR3

10

What is the most common lethal skeletal dysplasia?

Thanatophoric dysplasia

11

What are the classic features of thanatophoric dysplasia?

Cloverleaf skull in Type II
Micromelic limbs
Short ribs
Narrow thorax
Relative macrocephaly
Frontal bossing
Mid-face hypoplasia,
Reduced height of the vertebral bodies
Central nervous system abnormalities

12

Definition of micromelia

Shortening of the extremities involving the entire limb

13

Definition of rhizomelia

Shortening of the extremities involving the proximal segment

14

Definition of mesomelia

Shortening of the extremities involving the intermediate segment

15

Definition of acromelia

Shortening of the extremities involving the distal segment

16

Characteristics of osteogenesis imperfecta

Blue sclerae
hearing abnormalities
defective dentition
hyperlaxity of the joints
normal intelligence

17

Types and severity of OI?

Type I is the common mild form, type II is the perinatal lethal form, type III is the severe form, and type IV is the moderately clinically severe form.
More recently, an additional three types (V, VI, and VII) have been described.
The clinical severity of OI is type II> type III> types IV = V = VI = VII > type I.

18

What is campomelic dysplasia?

Symmetric bowing of the long bones of the lower extremities - acute femoral angulation, which typically occurs at the junction of the upper third and lower third of both femora, with resulting symmetrical shortening
Phenotypic sex reversal in some chromosomally male infants
Associated abnormalities including cleft palate, flat facies, micrognathia, hydrocephalus, and renal abnormalities.

19

What is short-rib polydactyly syndrome?

A group of rare, generally lethal skeletal dysplasias
Short horizontal ribs and long tubular bone changes that result in severe micromelia.