Achondroplasia is a bone growth disorder characterized by a stunted body and disproportionate limb size. This condition is one of the most common types of bone growth disorders.
Achondroplasia is characterized by short arms and legs, causing sufferers to have a stunted body (dwarfism). Achondroplasia is a rare disorder that only occurs in 1 in 15,000–40,000 births worldwide.
Achondroplasia
The average height of adult patients with achondroplasia is 131 cm in males and 124 cm in females. Even though they have different physical conditions, people with achondroplasia have a normal level of intelligence, like normal people in general.
Causes of Achondroplasia
Achondroplasia is caused by a genetic mutation in the FGFR3 gene, which is a gene that produces the Fibroblast Growth Factor Receptor 3 protein. This protein plays an important role in the process of ossification, or the process of changing cartilage into hard bone.
The FGFR3 gene mutation causes the protein to not function properly, thus interfering with the transformation of cartilage into hard bone. As a result, the bones grow shorter with an abnormal shape, especially the ones in the arms and legs.
FGFR3 gene mutations in achondroplasia patients can occur in two ways, namely:
Spontaneous mutations
Most cases of achondroplasia are caused by gene mutations that are not inherited from parents. This mutation occurs spontaneously, and the cause is unknown.
Inherited mutation
About 20% of cases of achondroplasia are inherited from parents. If one parent has achondroplasia, the percentage of children with the condition can be as high as 50%. However, if both parents have achondroplasia, the child's risk of also having this condition is as follows:
- 25% chance of a normally-bodied child
- 50% chance that a child will have one defective gene causing achondroplasia
- There is a 25% chance a child will inherit two defective genes causing fatal achondroplasia (homozygous achondroplasia).
Symptoms of Achondroplasia
From birth, babies with achondroplasia can be identified by their physical characteristics, such as:
- Short stature, far below the average height for his age.
- Short size of arms, legs, and fingers
- The head size is larger, with a prominent forehead.
- Misaligned and adjacent teeth
- Deformity of the spine, which can be in the form of lordosis (curvature forward) or kyphosis (curvature backwards),
- Narrow spinal column
- The limbs form the letter O.
- The soles of the feet are short and wide.
- Weak muscle strength
When to see a doctor
If your family members have a history of achondroplasia, have a genetic test before planning a pregnancy. The goal is to find out how much risk there is of this disorder being passed on to the fetus.
If you or your child is diagnosed with achondroplasia, it is advisable to undergo routine examinations at the doctor's office to prevent complications. It should be noted that the risk of developing achondroplasia complications can increase over time, so early treatment is expected to prevent worsening of symptoms.
Diagnosis of achondroplasia
Achondroplasia can be diagnosed in the womb or when the baby is born. The following is a full explanation:
After the baby is born
As a first step, the doctor will examine the patient's physical symptoms and conduct a debriefing with the patient's parents regarding family medical history. Achondroplasia is usually recognized by the disproportionately short limbs, which can be measured by a thorough physical examination.
To confirm the diagnosis, the doctor can also carry out further examinations with a DNA test. This test is done by taking a DNA sample from the blood to be examined in the laboratory. The DNA sample is used to detect possible abnormalities in the FGFR3 gene.
During pregnancy
A diagnosis of achondroplasia can also be made during pregnancy, especially for parents who have the condition. Several tests that can be done to detect achondroplasia are:
Gynecological ultrasound
Gynecological ultrasound is used to examine the condition of the fetus in the uterus and detect signs of achondroplasia, such as a larger than normal head size. Ultrasound can be done through the mother's abdomen (transabdominal) or through the vagina (transvaginal ultrasound).
FGFR3 gene mutation detection
Gene mutation detection while still in the womb can be done by examining a sample of amniotic fluid (amniocentesis) or a sample of placental tissue (the placenta), which is called chorionic villus sampling. However, this action is at risk of causing a miscarriage.
Treatment of Achondroplasia
Until now, there has been no method to completely treat achondroplasia. Existing treatments are limited to relieving symptoms or preventing and treating complications that arise. These treatment methods include:
1. Medical check-up
Routine medical check-ups aim to monitor the patient's body growth. This examination includes measuring the ratio of the upper to the lower body. Doctors will also continue to monitor the patient's weight to prevent obesity.
2. Hormone therapy
For children with achondroplasia, the doctor will recommend regular hormone therapy. The aim is to increase the child's bone growth so that he can have better posture as an adult.
3. Dental care
Dental treatment aims to improve the overlapping tooth structure experienced by sufferers of achondroplasia.
4. Antibiotics
Antibiotics can be used to treat ear infections that are common with achondroplasia.
5. Anti-inflammatory drugs
Anti-inflammatory drugs can be given to treat people with achondroplasia who also experience joint problems.
6. Operation
Surgery can be done to relieve symptoms or overcome complications that occur. Operations that can be performed include:
Orthopedic procedures
Orthopedics is performed by doctors to correct the O shape of the leg.
Lumbar laminectomy
A lumbar laminectomy is performed to treat spinal stenosis.
Ventriculoperitoneal shunt
This operation is performed if the patient has hydrocephalus. This procedure is performed by inserting a flexible tube (catheter) to remove excess fluid from the brain cavity.
Caesarean section
Pregnant women with achondroplasia have small pelvic bones, so it is advisable to deliver by caesarean section. A caesarean section is also necessary if the fetus is diagnosed with achondroplasia in order to reduce the risk of bleeding due to the fetal head being too large for normal delivery.
Tonsillectomy and adenoidectomy
Doctors can perform surgical removal of the tonsils (tonsillectomy) and removal of the adenoid glands (adenoidectomy). This is because sufferers of achondroplasia can experience deformities of the bones of the middle face, which increase the risk of causing swelling of the tonsils and adenoid glands.
Achondroplasia complications
There are various complications that can be experienced by sufferers of achondroplasia, including:
- Overweight and obesity
- Recurrent ear infections are due to the narrowing of the ear canal.
- Restrictions in movement due to deformity of the arms and legs
- Spinal stenosis, which is a narrowing of the spinal column that causes pressure on the nerves in the spinal cord,
- Hydrocephalus is the accumulation of fluid in the cavities (ventricles) of the brain.
- Sleep apnea, which is a condition where the rhythm of stopping breathing occurs during sleep,
Prevention of achondroplasia
Until now, it has not been known exactly how to prevent achondroplasia. However, if you suffer from achondroplasia or have a family history of achondroplasia, it is advisable to consult a doctor to find out more about the risk of passing achondroplasia on to your child.
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