Table 2.

Ages of occurrence of events for infants with SCID with no recognized prior affected family members.^*

	Number of Responses	Mean Age (weeks)	Median Age (weeks)
Age at onset of SCID symptoms	103	11	8
Age at diagnosis of SCID	101	26	24
Age at which definitive treatment instituted**	98	34	28
Age at death, if deceased	56	117	45

^*These infants became symptomatic prior to diagnosis of their SCID. In some of these families a positive family history was ultimately recognized retrospectively.

^**Definitive treatments in these infants included transplantation or enzyme replacement.