Causes of Achondroplasia

Achondroplasia /akon'dropla'zh/, a problem with the growth of cartilage in the growth plates of the long bones and skull. The bones fuse too soon. Growth stops and dwarfism results. One type, called familial achondroplasia, is inherited.

Achondroplasia is an inherited disorder of bone growth. It is one of the group of disorders that are collectively called chondrodystrophies or osteochondrodysplasias.

The disorder causes a type of dwarfism that is recognized by its characteristic normal to large-sized head, shortened arms and legs (especially the upper arm and thigh), a normal-sized trunk, and waddling gait. Achondroplasia is the most common type of dwarfism.

Achondroplasia is inherited as an autosomal dominant trait. However, the majority of cases, approximately 80%, appear as spontaneous mutations. If one parent has achondroplasia, the infant has a 50% chance of inheriting the disorder. If both parents have the condition, the infant's chances of being affected increase to 75%.

Information from National Institute of Health
1-20-2006