What is Achondroplasia?
It is a genetic disorder of bone growth and is the common cause of dwarfism. The literal meaning of Achondroplasia is “without cartilage formation”. Cartilage plays a crucial role in the early development of human beings. However, in children with achondroplasia, cartilage is unable to get converted in bones especially in the regions of arms and legs. It is one of the common forms of disproportionate short stature. Occurrence of achondroplasia is rare as it happens in one in 40,000 live births.
Achondroplasia is caused due to gene alteration in the Fibroblast Growth Factor Receptor 3 (FGFR3) gene. FGFR3 gene makes protein which is involved in converting cartilage to bone. The condition is mainly caused on people who have only a single copy of the normal FGFR3 gene and a single copy of FGFR3 gene mutation. While it is said to be inherited from parents, in most of the cases it was found that people with achondroplasia has average sized parents. The situation arises when FGFR3 occurs in one of the parent’s eggs or sperm cell before conception.
A person with achondroplasia has 50% chances of passing this to the new generations, which means, he or she may not have kids who are suffering from same. On the other hands, parents who are not having this syndrome may have kids who suffer from Achondroplasia. Usually, the new gene mutations which can cause this disorder are mainly the result of increased parental age. Mutations of couples with more than 35 years of age have more chances of a kid with symptoms of achondroplasia and as per the studies; they are more likely be inherited from father.
People with achondroplasia have an abnormal bone growth resulting in short stature affecting mainly the arms and legs. It is observed that the arms and legs are developed disproportionately. Persons suffering from achondroplasia also have a large head, short fingers, toes and a prominent forehead with small midface. The physical structure of the persons with achondroplasia, however, does not have any impact on the intelligence. The IQ of the persons appears to be normal and they also have a good life span. Because of weak muscle tone, infants born with achondroplasia found difficulty in walking and there might be some delays in learning other movements of the body. Spinal cord can be easily compressed which increases the chances of death during infancy. Other common health problems faced by achondroplasia affected persons include frequent ear infections, breathing problems, obesity, and sometimes back pan.
Achondroplasia can be diagnosed by clinical and X-ray findings. Preventative actions can be taken if the disease is diagnosed before child birth. The diagnosis is mainly done with the help of prenatal ultrasound and a DNA test which can be performed before birth of the child to determine the presence of homozygosity. In the condition of homozygosity, two copies of mutant gene are inherited which results in stillbirths. MRIs or CT scan can also evaluate the condition of spinal cord and how much it is compressed. The clinical features of achondroplasia like short limbs, prominent forehead, etc. (as mentioned above) can also be diagnosed at the initial stages. Leading clinical laboratories provide testing of FGFR3 gene mutation. Genetic testing is considered to be one of the best ways to identify mutations.
Achondroplasia has no treatments. For preventive measures and not to make the matters worse, children who are born with achondroplasia should have a proper checkup of their height, weight, etc. and parents are required to monitor their growth. More care should be taken during infancy as children born with this deformity have week spinal cord which can even cause death. Persons suffering from achondroplasia are prone to other health problems at early stages. Proper care should be taken to avoid obesity. Sometimes, adenoids and tonsils are removed surgically or a surgical opening is made in the airway. Few people have a myth that infusion of human growth hormone can help for the growth of muscles; however, it is not true. A surgery of limb lengthening can be done, but it is generally not recommended by the doctors. Surgery can also be performed to reduce pressure on the brain. Researchers are now exploring if gene based therapy can be done to treat any future occurrences of achondroplasia.
Achondroplasia is a non treatable disease. People with identifiable symptoms should be given enough support from society and they should be made realized that their IQ is normal and they can do normal activities. It is a myth that this condition is inherited as studies showed that over 85% of people with symptoms of achondroplasia have parents with normal structure. However, there is a possibility that if both or one of the couples have achondroplasia, there is a 25-50% chance of gene mutations which will result in dwarf children.