Pseudoachondroplasia

Pseudoachondroplasia is a type of short-limb dwarfism. It is a genetic autosomal dominant disorder. It is generally not discovered until 2-3 years of age, since growth is normal at first. Pseudoachondroplasia is usually first detected by a delay in crawling, walking, or a curious, waddling gait.

Presentation
As the growth rate slows, lumbar lordosis and rhizomelic shortening of the limbs becomes apparent. Most pseudoachondroplasiacs are 80-130 centimeters (31-51 inches) in height. Knee deformities (bow-leggedness, knock-knees) are also common. Joint hypermobility at the wrist and fingers can be seen, although mobility at the elbow is slightly impaired. Osteoarthritis is a common characteristic of pseudoachondroplasiacs.

Genetics
The gene for pseudoachondroplasia was located, and is called cartilage oligomeric matrix protein (COMP).