Achondroplasia Flashcards
True or False: Achondroplasia is the most common condition associated w severe disproportionate short stature
True!
How is Achondroplasia inherited?
Autosomal dominent, although 75% are NEW dominant mutations
True or false: advanced maternal age is associated with increased risk of achondroplasia
FALSE! Advanced paternal age is associated with achondroplasia and occurs almost exclusively in spermatogenesis
What gene is affected in achrondroplasia?
Fibroblast growth factor receptor 3 (FGFR3) gene
What can happen if both parents have achondroplasia and they decide to have a child?
Can have two bad scenarios:
- Double heterozygosity (life-threatening)
- Homozygosity (stillborn/die shortly after birth)
What are 2 MSK features of achondroplasia
- Bowing of lower legs
2. Proximal limb shortening
What is a common ENT complication?
Otitis media causing hearing loss
What are 2 developmental features of achondroplasia?
- Delayed motor milestones
2. Normal intelligence
What are 2 respiratory features of achondroplasia
- Restrictive pulmonary disease if <3yo
2. OSA
Name 4 facial features of achondroplasia
and 3 Body features
- Flattened midface
- Prominent forehead
- Macrocephaly
- Dental malocclusion
- Normal length trunk
- Trident shaped hands
- Proximal shortening of long bones
What are 4 uncommon but serious complications associated with achondroplasia?
- Hydrocephalus
- Craniocervical junction compression
- Upper a/w obstruction
- Thoracolumbar kyphosis
Name 5 radiographic features of achondroplasia
- Square shaped pelvis with a small sacrosciatic notch
- Short pedicles of vertebrae
- Proximal femoral lucency
- Chevron shape of distal femur (inverted V shape)
- Proximal shortening of long bones
How do you diagnose achondroplasia?
Clinically, only do molecular testing if atypical.
Why are CT/MRI commonly done in children with achondroplasia?
To asses the foramen magnum size.
note you should monitor head circumference closely in the first 2 years
How often should hearing be checked in achondroplasia?
Annually.
What are 3 special considerations for children with achondroplasia.
- No unsupported sitting until trunk muscles fully developed, and avoid curved or “C sitting” in the first year of life as it can increase risk of kyphosis
- Greater than average sweating is normal
- Psychosocial impact of short stature (adapt environment)
What is the natural history of achondroplasia?
- Average adult height approx 4ft
- Normal lifespan
- Normal intelligence
What is a longterm complication that can occur with achondroplasia?
- Lumbosacral spinal stenosis w compression of spinal cord/nerve roots
What are 2 special considerations for pregnant women with achondroplasia
- Mom can have respiratory compromise
2. C/S required for delivery due to small pelvis size.
