. 2023 Jan 27;60(9):910–917. doi: 10.1136/jmg-2022-108920

Table 3.

Components of genetic counselling for a DNM discovered in a child

Factor	Impact on recurrence risk
Parental gonadal mosaicism	Depending on the type and VAF of the mutation. Mosaicisms in mothers double the probability of recurrence, but the probability is increased more than 50 times in fathers¹¹
DNMs shared by siblings	Increases to 23.0% from 1.1%¹⁴
Mutation origin	Approximately 80% of all DNMs arise in the paternal allele, but mutations of maternal origin determine a higher recurrence risk than paternal mutations^{11 46}
Age of mother	Unlikely to change with maternal age¹¹
Age of father	Despite an increased risk of a first afflicted offspring, the recurrence risk from paternal mutations diminishes with age¹¹

DNM, de novo mutation.