Achondroplasia
Cause of Disorder
Achondroplasia is a single gene disorder that causes birth defects and results in short-limbed dwarfism. It is caused by mutations to the FGFR3 gene on chromosome 4. This gene prevents the growth of cartilage at the growth plate. FGFR3 encodes a protein called Fibroblast Growth Factor Receptor 3. This protein is the site of action of a major growth factor responsible for lengthening bones. When this growth factor cannot act properly due to the absence of its receptor, the growth of bones, at the growth plate's cartilage, is slowed. This leads to shorter bones, abnormally shaped bones, and shorter stature. It is caused by an autosomal dominant gene mutation.
Symptoms
•Short stature, a long trunk, and shortened limbs, which are noticeable at birth
•An adult height of between 42-56 inches
•A head that is large and a forehead that is prominent
•Portions of the face can be underdeveloped
•At birth, the legs appear straight, but as a child begins to walk, he or she develops a knock-knee or bowed-leg deformity
•The hands and the feet appear large, but the fingers and toes are short and stubby
•Children may develop an excessive curve of the lower back and a waddling walking pattern
•Dental problems from overcrowding teeth
•Neurologic and respiratory problems
• Fatigue, pain, and numbness in the lower back
Treatments
Growth hormones may be subscribed and can achieve a moderate change in growth in some children. Surgeries are sometimes needed to correct certain skeletal deformities, such as a Laminectomy to relieve spinal compression and Osteotomy to correct bowed legs.
Cures
There is no cure for Achondroplasia.
Screening
Fetal ultrasound – may show excessive amniotic fluid surrounding the fetus
Images taken of bodily structures using – Radiographs, X-rays, MRI scan, and CT scan
DNA testing – for the FGFR3 gene mutation