Fig. 1.

Proportion of monogenic variants by age at onset. Black and gray bars show whether causative variants were detected or not, respectively. The rates were lower at 1 year (5%) and 2 years (12%) of age but peaked at 3 years of age (21%). The rate was again lower for those over 13 years of age, but the rates in the age groups 4–6 and 7–12 years were relatively high. Abbreviation: y.o., years old