Overview Of Achondroplasia (ACH)
Achondroplasia is a disorder that impacts bone growth. It is known to cause the most common variety of dwarfism.
Commonly Associated With
Achondroplastic dwarfism
Cause Of Achondroplasia (ACH)
Achondroplasia belongs to a group of disorders that medical professionals refer to as either chondrodystrophies or osteochondrodysplasias.
Achondroplasia is considered a genetic trait, and can be inherited as an autosomal dominant trait. This means that the child only needs one defective gene from one parent to inherit the disorder. If one of the parents has achondroplasia, the child will have a 50% chance of inheriting the disorder. If both parents have the disorder, the child’s chances of being affected increase to 75%. (The reason the percentage is not 100 is that when 2 copies of the defective gene are present, the child tends to be stillborn or die shortly after birth, and is therefore not in the statistics)
Most cases of achondroplasia occur due to spontaneous mutations, meaning that neither parent has the condition, but they produce a child that does.
Symptoms Of Achondroplasia (ACH)
The typical appearance of achondroplastic dwarfism are present at birth. Symptoms can include:
- A disproportionately large head-to-body size differential
- Bowed legs
- An abnormal structure of the hands, with an unusual spacing between the ring and long fingers
- Spine curvatures, such as lordosis or kyphosis
- A prominent forehead (often referred to as frontal bossing)
- A short stature that is significantly below average for a person of the same sex and age
- Decreased muscle tone
- Shortened legs and arms, especially in the upper thigh and arm
- A narrowing of the spinal column, called spinal stenosis
Exams and Tests
Doctors often see excessive amniotic fluid surrounding the fetus on prenatal ultrasounds, and use this as a method of diagnosis.
Examination of the infant after they are born can show an increased head size, especially for the front-to-back. There can also be signs of hydrocephalus (excess fluid within the brain that can cause a harmful increase in pressure)
X-rays of the long bones in the newborn can reveal achondroplasia as well.
Treatment Of Achondroplasia (ACH)
There are no specific treatments available for achondroplasia. However, abnormalities associated with the condition, such as spinal cord compression and spinal stenosis, should be addressed when or if they cause problems for the patient.
Outlook (Prognosis) Of Achondroplasia (ACH)
Those with achondroplasia rarely reach 5 feet (1.5 meters) tall. It rarely affects their intelligence, and they are most often in the normal range. As stated previously, infants who receive 2 copies of the defective gene are often stillborn, and those who are not do not tend to survive beyond a few months.
Possible Complications
Health problems that can develop include:
● Lung problems due to a smaller than normal ribcage
● Breathing problems due to a small upper airway and/or pressure on the region of the brain that normally controls breathing
When to Contact a Medical Professional
Those with a family history of achondroplasia may find it helpful to discuss their options with a health care provider if they plan to have children in the future.
Prevention Of Achondroplasia (ACH)
Genetic counseling can be a helpful resource for prospective parents when one or both have achondroplasia. However, given that achondroplasia most often appears spontaneously, prevention is not always possible.
