Achondroplasia - Causes, Diagnosis, Treatment and Prevention

What Is Achondroplasia?

Achondroplasia is a type of bone disorder in which the affected individual has disproportionately developed bones. This might result in dwarfism. Dwarfism is a condition in which the affected individual appears very short, compared to other individuals of the same age. The hands and legs of the achondroplasia patients are relatively small. Achondroplasia is the most commonly occurring disproportionate dwarfism. The most important characteristic of achondroplasia is the abnormality in the growth of the bones. The spine, skull, and other parts of the bone might be affected. The term 'achondroplasia' was first used in 1878 by Mr. Parrot, referring to the absence of cartilage formation.

How Does Achondroplasia Occur in Children?

In children, strong and flexible tissues are found as a result of achondroplasia. The head appears large, and the arms and legs are very short. The average height of a boy with achondroplasia is about four feet and four inches. The average height of a girl with achondroplasia is around four feet and one inch. The child's intelligence level is not affected, and they can enjoy a normal lifespan. Children require constant support from a health care provider.

What Is the Epidemiology of Achondroplasia?

The highest number of affected people are found in the United States of America. This skeletal disorder is known to affect one out of every 40,000 people. Reports from the European Surveillance of Congenital Anomalies (EUROCAT) suggest an incidence of 3.72 percent in every 100,000 births. This condition can affect both male and female genders equally. It is also known to affect people belonging to all races. But, achondroplasia can occur in greater ranges if the parents are also affected.

What Are the Types of Achondroplasia?

Achondroplasia is categorized into three types depending on the site of involvement of the limbs. They are:

• Acromelic: In this type, the distal portion of the limb is affected.

• Mesomelic: In the mesomelic type, the middle part of the limb is commonly affected.

• Rhizomelic: In the third type, the proximal portion of the limb is affected. In addition to this, the hands, legs, feet, and forearms are extensively involved compared to the other types.

What Are the Special Features of Achondroplasia Patients?

Achondroplasia patients have one notable unique feature. Most health conditions might interrupt the occupation and routine life of an individual. But, patients who are affected by achondroplasia have a strong cartilage formation that will encourage them to become wrestlers and bodybuilders. The short stature of the affected individuals will not stop them from choosing their profession as fitness persons.

What Are the Causes of Achondroplasia?

The various causes of achondroplasia are:

• Genetics: More than 80 percent of the reported cases are affected by genetic mutations. When both parents are affected by achondroplasia, more than 50 percent of their kids have the possibility of developing achondroplasia.

• Abnormality in the Growth Factor: Fibroblast is an important component that is associated with the cells’ growth. They play an important role in the functioning and healing of wounds. Any mutation in the fibroblast growth factor- 3 is responsible for the occurrence of achondroplasia.

What Are the Signs and Symptoms of Achondroplasia?

The various signs and symptoms associated with achondroplasia differ according to age. At birth, achondroplasia produces the following symptoms.

• Short thighs and arms when compared to the whole body height.

• A short middle and ring finger that always points away from one another.

• Flattened nose.

• Large size head with a broad forehead.

• Bowed lower legs.

• Crowded teeth.

• Instability of shoulders when the child begins to walk.

• A curved lower spine will result in a condition called lordosis or kyphosis.

• Additional spaces between the fingers will result in trident hands.

• The foot appears flat and broad.

• Poor tonicity of the muscles and loose joints.

• Slow breathing.

• Delayed development.

• Middle ear infections that might result in hearing loss.

What Are the Complications Faced by Patients With Achondroplasia?

1. Patients who are affected by achondroplasia suffer various complications associated with motor ability.

2. In addition to this, they have obesity problems that might cause difficulty in the standard walking patterns of the individual.

3. Lodging of water in the brain will result in hydrocephalus.

4. The adults might suffer from spinal stenosis in which there is a narrowing of the spinal canal that will result in the compression of the spinal cord.

5. A severe case of spinal stenosis might result in the death of the patient.

6. Breathing problems might occur.

7. Dental complications might include severe malocclusion, and they need the help of an orthodontist to correct it.

When the patient experiences the following symptoms, consult a medical professional as soon as possible:

• Prolonged breathing difficulty.

• Weakness and tingling sensation in the legs.

• Back pain.

How Is Achondroplasia Diagnosed?

• Fetal Ultrasound: The diagnosis of achondroplasia can be made using a fetal ultrasound. This is done during pregnancy. The ultrasound waves help in identifying the abnormally large shape of the head and hydrocephalus condition.

• DNA Test: The abnormal pattern in the genes and DNA of the child can be detected in the DNA testing procedure.

• Radiologic Examination: This is usually done after childbirth. The narrowing of the spinal canal and deformity in the bones are detected using radiologic findings. The length of the bones are calculated and used for making the confirmatory diagnosis for achondroplasia.

• Blood Test: Blood tests are helpful for finding the defects in fibroblast growth factor-3.

What Are the Treatment Options for Achondroplasia?

There is no exact cure for achondroplasia. The treatment plan can be aimed at providing comfort from the painful symptoms. Correcting the levels of growth hormone has no known advantages. The main aspect of treatment should be aimed at treating the problems associated with the bone. The pain caused due to the abnormal growth of the bones can be relieved with the help of suitable painkillers. In order to overcome the risk of hearing loss, the infections in the ear should be treated at a very earlier stage. As the dental problem is very common in achondroplasia patients, alignment of the teeth should be done under the guidance of a qualified orthodontist. Surgical procedures might be required to treat the bowing of the legs and kyphosis conditions. Patients who are suffering from breathing problems might require removal of the tonsils to correct the condition, but this surgical procedure might invite other problems. The patient might require breathing support if there are severe breathing issues.

How Can You Prevent Achondroplasia?

There is no specific method to prevent achondroplasia. If a family history of achondroplasia is detected, then genetic counseling should be taken. This will prevent the inheritance of achondroplasia to the next generation. The possibility of passing the condition to the kids will be discussed by a genetic counselor. General health checkups should be regularly done by both the affected parents and their offspring.

Conclusion

There is no specific treatment or preventive strategy for achondroplasia. But this should not stop you from consulting healthcare professionals. Talking to a genetic counselor and undergoing premarital counseling and tests can help make a decision about having children.