Achondroplasia

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Achondroplasia is a disorder of bone growth that causes the most common type of dwarfism.

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 a 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 may be inherited as an autosomal dominant trait, which means that if a child gets the defective gene from one parent, the child will have the disorder.

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However, approximately 80% of cases appear as spontaneous mutations. This means that two parents without achondroplasia may give birth to a baby with achondroplasia. 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%.

Review Date: 12/18/2006
Reviewed By: Daniel Rauch, MD, FAAP, Director, Pediatric Hospitalist Program, Associate Professor of Pediatrics, NYU School of Medicine, New York, NY. Review provided by VeriMed Healthcare Network.