The inheritance pattern of achondroplasia
Achondroplasia is an autosomal dominant disease. An autosomal dominant design means one copy of the mutated gene per cell is enough to express the disorder. About 80 percent of people with achondroplasia have healthy parents; these cases result from new mutations in the FGFR3 gene.
In rare cases, people with achondroplasia have received an altered FGFR3 gene from one or two affected parents. People who received two mutated copies of this gene complain a critical kind of achondroplasia that causes acute shortening of the bones and an undeveloped rib cage, which is incompatible with life. These individuals are usually stillborn or die shortly after birth due to respiratory failure.
