Skeletal Dysplasias Flashcards
What disease has absent or hypoplastic clavicles?
cleidocranial dysplasia; RUNx2/CBFA1 mutation
What is the mutation in clediocranial dysplasia?
RUNX2/CBFA1; will see absent clavicles (due to defect in intramembranous ossification)
What are physical exam findings of cleidocranial dysplasia?
1) Proportionate dwarphism
2) hypermobility of shoulders
3) frontal bossing
4) wormian bones
5) abnormal hip ROM (severe coxa vara)
What is the genetic defect a/w Multiple Epiphyseal Dysplasia?
COMP (cartilage oligomeric matrix protein); caused by failure of secondary ossification formation (epiphysis)
What are radiographic findings in MED?
1) Double layer patella
2) bilateral and symmetric appearance that mimics Legg-Calve-Perthes
3) short stunted metacarpals
4) Valgus knee
What is the inheritance pattern for achondroplasia?
AD; due to mutation of FGF3 on Ch4
Results in abnormal chondroid production
Is a quantitative mutation
What is the most likely cause of disability in achondroplastic dwarves?
Lumbar spinal stenosis due to short pedicles, can also have thoracolumbar kyphosis; leads to:
pseudoclaudication and standing discomfort
numbness and paresthesias
subjective weakness
What neurologic condition may need urgent decompression in achondroplastic dwarves?
Foramen magnum compression
What type of shortening is typical of achondroplastic dwarves?
rhizomelic; proximal long bones shorter than distal long bones
What physeal zone is affected by achondroplasia?
Zone of proliferation
What is the mutation a/w diastrophic dysplasia?
Mutation of DTDST gene (SLC26A2) on chromosome 5 which encodes for sulfate transporter protein; AR
What are physical features of diastrophic dwarves?
1) Cauliflower ears
2) Hitchhiker’s thumb
3) Severe cervical kyphosis
4) Cleft palate
5) Rigid equinocavovarus
