What Is Achondroplasia?
How Do I Inherit Achondroplasia?
Achondroplasia is the result of inheriting an abnormal gene. It is an autsomal dominant trait. (Kaneshiro, 2013) This means that in order for you to have achondroplasia, you must inherit one abnormal gene from either of your parents. In other cases, achondroplasia is spontaneous. Studies have shown that 80% of achondroplastic people have normal parents with no signs of affected genes. (Kivi, 2012)
Both parents are affected. The chance of having an unaffected child is 25% while the chance of an afffected child is 50%.
In this case one parent is unaffected and the other is affected. The chances of having an affected child are even to the chances of having an unaffected child. (1:1 ratio)
Causes
Achondroplasia is caused by mutations in the fibroblast growth factor receptor 3 (FGFR3) gene on chromosome 4. (DNA Learning Centre, 2014) The FGFR3 gene instructs the body to make a protein that is necessary for bone growth. (Genetics Home Reference, 2012) Due to mutations in this gene, bone growth is disrupted.
Chromosome 4
The FGFR3 gene
Who is Affected By Achondroplasia?
Achondroplasia occurs in 1 in 15000 to 40000 births (depending on the source). (Genetics Home Reference, 2014) It is not exclusive to a race or gender. In fact males and females have equal chancs of inheriting achondroplasia. (Parikh, 2014) In total, there are 150,000 people worldwide who are affected by achondroplasia. (Parikh, 2014)