Achondroplasia is a bone disorder that affects about 1 in every 10,000 infants. This disease is caused by a mutation in the FGFR3 gene that impairs the growth of bone in the limbs and causes abnormal growth in the spine and skull.
There is an approximate of about 20-50% of children who are suffering with achondroplasia will experience a neurological impairment. This is caused by compression created as they literally grow faster than their bones.
The stunted bone growth at the base of the skull and the spine can cause the spinal cord and brain stem to become compressed.
Achondroplasia can further lead to key nervous system structures such as the brain stem, spinal cord, spinal nerve roots and cerebrospinal fluid (CSF) spaces to also compress.
How is achondroplasia diagnosed?
Achondroplasia can easily be diagnosed prior to birth via fetal ultrasound or after birth via complete medical history and physical examination.
There is now an availability of DNA testing before birth to confirm fetal ultrasound findings for parents who are at increased risk for having a child with achondroplasia.
One should be looking carefully for signs of muscle weakness, changes in bowel or bladder function, asymmetrical reflexes or respiratory problems like sleep apnea, if his child has been diagnosed with achondroplasia.
If any of above mentioned symptoms is present in your child, you’ll want to obtain a thorough work-up of him by consulting a pediatric neurologist, pediatric neurosurgeon or pediatric orthopedist, along with magnetic resonance imaging (MRI) of the child’s head, neck or spine.
Symptoms of achondroplasia
The following are the most common symptoms of achondroplasia. However, each child may experience symptoms differently. Some of the symptoms of achondroplasia may include:
- shortened arms and legs, with the upper arms and thighs more shortened than the forearms and lower legs
- big head size with prominent forehead and a flattened nasal bridge
- crowded or misaligned teeth
- Curved lower spine – a condition also called lordosis (or "sway-back") which may lead to kyphosis, or the development of a small hump near the shoulders that usually goes away after the child begins walking.
- bowed lower legs
- flat feet which are short and broad
- Extra space between the middle and ring fingers (Also called a trident hand.)
- poor muscle tone and loose joints
- frequent middle ear infections which may lead to hearing loss
- normal intelligence
- delayed developmental milestones like walking
The symptoms of achondroplasia may resemble other problems or medical conditions. Always talk with your child's doctor for a diagnosis.
Treatment for achondroplasia
A surgeon can remove bone and ligaments from the problem area to make more room for neural structures, if a dangerously compressed region of the foramen magnum or spinal column is found.
Surgical decompression is considered to be the most successful when it is performed quickly as symptoms are allowed to progress for months or years can become permanent.
One end is placed in the child’s ventricle and the other in his or her abdomen. CSF is allowed to flow at a controlled pace out of the child’s head into his or her abdomen, where it can be quickly and safely absorbed into the bloodstream.
When symptoms are determined and acted upon in a timely manner, modern medical and surgical care allows achondroplastic children to grow up with intellectual and social capacities equal to that of other children.