Achondroplasia is an inherited disorder affecting bone growth. Although the name means "without cartilage formation," the body fails to convert cartilage into bone. Affecting an average of 1 in 25,000 births, this defect results in short stature and disproportionate limbs. Patients may display an abnormally large head, long torso and short limbs. Upon closer inspection, you may notice a pronounced forehead, and trident-like fingers (meaning the 3rd and 4th digits diverge to opposite sides). Patients may also exhibit abnormalities in joint movement; for instance, the elbow may not be capable of extending fully, while the knee may hyperextend without intention. Lordosis may be apparent in the lumbar spine, and the patients legs are often bowed. As seen in the MRI image above, patients also display a depressed nasal bridge, and a narrowed foramen magnum. While Achondroplasia patients tend to run slightly behind schedule with motor development, intelligence is not compromised. Megacephally, enlargement of the brain, is also common among these patients.
Diagnosis of Achondroplasia can come from many modalities. For example, before birth the defect may be detected with the use of ultrasound. If either of the parents, or both, are affected a molecular diagnosis may also be key. This disorder is an autosomal dominant trait, and all those who have the gene will have Achondroplasia. While these patients may lead normal lives, continued monitoring is often required especially of growth measurements. Weight management is also key because obesity can aggravate the existent joint problems.
