At what paternal age is there an increased risk for single gene disorders such as achondroplasia?

The correct answer is based on the understanding that paternal age plays a significant role in the risk of genetic mutations associated with certain conditions, including single gene disorders like achondroplasia. As men age, the number of new mutations in their sperm can increase due to several biological factors, including the accumulation of mutations over time as germ cells divide.

Research has demonstrated that older paternal age is specifically correlated with an increased incidence of spontaneous mutations that can lead to conditions such as achondroplasia, which is caused by a mutation in the FGFR3 gene. Data suggests that the risk for new mutations significantly rises around the age of 40 and older, making this age range particularly important in assessing the risk for these genetic disorders.

Younger paternal ages, such as 30-35 or 35-40 years, do not show the same elevated risk for such mutations. Similarly, while the risk continues to rise with advancing age, distinguishing between the age ranges helps clarify when the statistical increase in mutation rates becomes significant. Thus, the age range of 40-50 years and older is particularly notable in this context.