Brona+C

RAFT Project- Genetic Disorders Role: Genetic Counselor Audience: Future Parents Format: Wiki Page Topic: Achondroplasia By: Brona Campbell

Description:
Achondroplasia is a disorder of bone growth that causes the most common type of dwarfism. Achondroplasia literally means "without cartilage." Although, this is not completely true. the real problem is when the cartilage has difficulty converting to bone, especially in the long bones of the arm.

Symptoms/Side Effects:

 * ring and middle finger may diverge forming a trident look
 * bowed legs
 * decrease muscle tone
 * large head and prominent forehead
 * shortened arms and legs (especially in the upper arm an thigh)
 * short statue male adults: 4'4 female adults: 4'1
 * spinal stenosis (narrowing of the spinal column that causes pressure on the spinal cord)
 * ear infections
 * obesity
 * crowed teeth

Common Treatments:
There is no specific treatments to treat achondroplasia, but some abnormalities including spinal stenosis and spinal cord compression, should be treated when they cause problems

Prevention/control of the Disease:
If one parent or both parents have achondroplasia and want to have a child, it would be best to schedule an appointment with a genetic counselor.
 * Prevention is not always possible because achondroplasia mostly occurs spontaneously.**

FGFR3 Gene:
the FGFR3 gene is a mutation that causes achondroplasia. FGFR3 is an acronym for fibroblast growth factor receptor 3. Normally, the protein made by the gene is a receptor that regulates bone growth by limiting the formation of bone from cartilage. But, people with achondroplasia, there FGFR3 gene mutates causing the receptor to be overly active, which intereres with ossification and leads to the disterbances in the bone growth seen with this disorder

How is it Inherited?:

 * even though achondroplasia mostly occurs spontaneously, it can also be an autosomal dominant trait, and a child receives it from one defective gene of a parent. **

if one parent has the disease, there is a 50% chance of passing it down to their child, but i both parents have achondroplasia, there is a 75% chance of their child receiving the defective gene. Surprisingly, 80% of the time achondroplasia gets passed down to a child when neither of their parents have the defective gene.

**Populations with Predispositions to Achondroplasia:**
occurs in 1 to 15,000 in 40,000 births, and it occurs in all races ad both males and females equally.

** W ** **ork Cited:**
Kaneshiro, Neil Zeive, David. "Achondroplasia." //PubMed Health,// A.D.A.M. http://www.ncbi.nlm.nih.gov/pubmedhealth 13 Nov. 2011. 30 Jan. 2013.

Stoppler, Melissa. "Achondroplasia." //MedicineNet.com.// http://www.medicinenet.com 6 Feb. 2012. 30 Jan. 2013

Schoenstadt, Arthur. "Achondroplasia Symptoms." and "What Causes Achondroplasia?" 17. Aug. 2008.

"Birth Defects." //March of Dimes.// http://www.marchofdimes.com/baby/birthdefects_achondroplasia.html 2008. 2 Feb. 2013