A new estimate of the achondroplasia mutation rate.

An estimate is derived of the mutation of achondroplasia based upon the accumulated data of recent newborn studies in four cities. In a total of 242,257 births, seven infants had mutant achondroplasia, the diagnosis being confirmed radiologically in all but one. From this, the rate of mutation of the normal to the achondroplasia allele is calculated to be 1.4 x 10(-5) +/- standard error 0.5 x 10(-5). Certain shortcomings of this estimate are discussed.