Table 3. Frequency of bilateral disease and median age at diagnosis of sporadic tumors in the three molecular Groups.

	Total	Bilateral		Age at diagnosis (months)
	n	n	%	median
All tumors classified	64	7	11%	38
Group 1	40	7	18%	42*
1A - H19 epimutation	23	7	30%*	42
1B - pUPD 11p15	17	0	0%	43
Group 2	8	0	0%	14*
Group 3	16	0	0%	39

^*Statistically significant associations. P values are given in the text. pUPD: paternal uniparental disomy.