How does achondroplasia affect the body?

Achondroplasia causes a child’s arms and legs to grow much shorter in proportion to their regular-sized torso. It can also create a larger head size than normal. On average, males affected by achondroplasia reach a height of about 52 inches, or 4 feet, 5 inches. Females affected by achondroplasia reach an average height of 49 inches, or 4 feet, 1 inch.

What causes achondroplasia?

Achondroplasia is caused by a mutation in the FGFR3 gene that impairs the growth of bone in the limbs and causes abnormal growth in the spine and skull.

Is achondroplasia inherited?

Achondroplasia is most often not inherited, with about 80 percent of cases resulting from a new mutation that neither of the parents possessed. A person with achondroplasia who is planning to have a child with someone without achondroplasia has a 50 percent chance of having a baby with the condition. If both parents have achondroplasia, the chance of having a child with the condition is still 50 percent, but the chance of having a child with normal stature is 25 percent.

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