Achondroplasia
Overview
Achondroplasia is a genetic disorder that is the most common cause of dwarfism, a condition characterized by short stature. It is a form of short-limbed dwarfism, meaning that the arms and legs are disproportionately short compared to the torso. The condition is caused by a mutation in the FGFR3 gene, which is involved in the development and maintenance of bone and brain tissue.
Genetics
Achondroplasia is an autosomal dominant disorder, which means that an individual only needs to inherit one copy of the mutated gene to develop the condition. Most cases of achondroplasia are the result of new mutations and occur in people with no history of the disorder in their family. The FGFR3 gene mutation responsible for achondroplasia results in an abnormally active protein that interferes with skeletal development, leading to the characteristic features of the condition.
Symptoms and Diagnosis
The symptoms of achondroplasia are usually apparent at birth. The most common features include short stature, disproportionately short arms and legs, a large head with a prominent forehead and flat nasal bridge, and a trident hand (a hand in which the space between the third and fourth fingers is wider than normal). Other symptoms may include spinal stenosis (narrowing of the spinal canal), lordosis (excessive inward curvature of the spine), and recurrent ear infections due to narrow eustachian tubes.
Diagnosis of achondroplasia is usually based on the characteristic physical features. Genetic testing can confirm the diagnosis by identifying the FGFR3 gene mutation. Prenatal diagnosis is possible through amniocentesis or chorionic villus sampling (CVS), which can detect the FGFR3 mutation in fetal cells.
Treatment and Management
There is currently no cure for achondroplasia, and treatment focuses on managing the symptoms and preventing complications. This may involve physical therapy to improve muscle tone and strength, and surgery to address skeletal abnormalities. Regular monitoring is necessary to detect and manage potential complications such as spinal stenosis and ear infections.
Prognosis and Life Expectancy
With appropriate management, individuals with achondroplasia can lead healthy, productive lives. Life expectancy is generally normal, although there may be an increased risk of certain health problems such as obesity and sleep apnea. It is important for individuals with achondroplasia and their families to have access to appropriate support and resources to manage the condition.