Achondroplasia: The Most Common Form of Dwarfism

1. Introduction

Achondroplasia is a genetic disorder that is characterized by short stature and abnormally short limbs. This condition is caused by a mutation in the FGFR3 gene, which is responsible for the proper development of bones and joints. Achondroplasia is the most common form of dwarfism, accounting for about 70% of all cases.

2. What is Achondroplasia?

Achondroplasia is a genetic disorder that is characterized by short stature and abnormally short limbs. This condition is caused by a mutation in the FGFR3 gene, which is responsible for the proper development of bones and joints. Achondroplasia is the most common form of dwarfism, accounting for about 70% of all cases.

3. The Genes Involved in Achondroplasia

The FGFR3 gene provides instructions for making a protein called fibroblast growth factor receptor 3. This protein is involved in the development and maintenance of bone and joint tissue. Mutations in the FGFR3 gene cause achondroplasia, the most common form of dwarfism.

4. How is Achondroplasia Inherited?

Achondroplasia is inherited in an autosomal dominant pattern, which means one copy of the mutated FGFR3 gene in each cell is sufficient to cause the disorder. In most cases, the mutated gene is inherited from an affected parent. Approximately 75% of people with achondroplasia have parents of average height. However, 25% of affected individuals are born to two parents with normal stature; these cases occur when each parent carries one copy of the mutated gene (referred to as carriers). If both parents are carriers of a mutation in the FGFR3 gene, their children have a 25% chance with each pregnancy of inheriting two mutated copies of the gene (and being affected with achondroplasia), a 50% chance of inheriting one mutated copy and one normal copy (and being carriers), and a 25% chance of inheriting two normal copies (and having no involvement with this disorder). People who inherit only one mutated copy of the FGFR3 gene do not usually experience any signs or symptoms associated with achondroplasia because they also have one normal copy that compensates for the mutated copy. However, they can pass on the mutation to their children.

5. What are the Clinical Features of Achondroplasia?

Achondroplasia causes abnormalities in bone growth, resulting in dwarfism and other skeletal abnormalities. The average height for adults with achondroplasia is 4 feet (122 cm). People with this disorder typically have disproportionately short limbs, particularly the upper arms and thighs, compared to their trunk ( torso). In addition, their hands and feet may be small and stubby, and their fingers may be stubbier than usual. As infants grow older, it becomes increasingly difficult for them to turn their heads because their skulls are relatively large compared to their bodies; this can lead to compression of the spinal cord (spinal stenosis). In addition to skeletal abnormalities, people with achondroplasia may also experience hydrocephalus, sleep apnea, recurrent ear infections, and defects in the structure of the larynx (laryngeal stenosis).

6. Management and Treatment of Achondroplasia

There is no cure for achondroplasia, but there are treatments available to help manage the symptoms associated with this disorder. Growth hormone therapy is often prescribed for children with achondroplasia to help them reach their full potential height. There are also a number of surgeries that can be performed to correct some of the skeletal abnormalities associated with this disorder, such as lengthening of the bones or decompression of the spinal cord. In addition, people with achondroplasia should be monitored closely by a team of specialists to ensure that they are receiving the best possible care.

7. Prognosis of Achondroplasia

The life expectancy for people with achondroplasia is typically normal. However, there are a number of complications associated with this disorder that can affect quality of life and life expectancy. These complications include spinal stenosis, which can lead to paralysis; hydrocephalus, which can cause brain damage; and laryngeal stenosis, which can restrict breathing. In addition, people with achondroplasia are at an increased risk for certain types of cancer, such as osteosarcoma. With early diagnosis and prompt treatment, most people with achondroplasia live happy and healthy lives.

If you or someone you know has achondroplasia, there are a number of resources available to help you cope with this disorder. The following organizations can provide you with information and support:

Achondroplasia Family Network: www.achondroplasia.org
Achondroplasia Support Group: www.achondroplasiasupportgroup.com
Little People of America: www.lpaonline.org

FAQ

Achondroplasia is a genetic disorder that results in dwarfism.

Achondroplasia is caused by a mutation in the FGFR3 gene. This gene provides instructions for making a protein that is involved in bone growth. The mutation leads to abnormally short bones and an unusually large head.

Achondroplasia can be inherited in one of two ways: -It can be passed down from parents to their children through what’s called an autosomal dominant pattern of inheritance. In this case, one parent must have the mutated gene in order for the child to inherit the disorder. -Achondroplasia can also occur as a spontaneous mutation, which means it occurs randomly with no family history of the disorder.

Symptoms of achondroplasia include: short stature, disproportionate shortening of arms and legs, restricted movement at elbows and knees, small hands and feet with shortened fingers and toes, enlargement of space between first and second toes (clinodactyly), bowed thighs, curvature of the lower spine (lordosis), Kyphosis (an outward curve) of the upper back ,relative prominence of forehead ,and underdevelopment of midface .