Table 2. Summary of output from the ENU screen including number of pedigrees analysed along with mutant discovery and mutations cloned.

	Total	Early	Late
Pedigrees	157	—	—
Active pedigrees	23	—	—
Pedigrees with phenotypes	72	58	26
Number of mutants	105	78	27
Mapped mutations	81	58	23
Cloned mutations	44	32	12	Missense	Stop gained	Splice mutant
				19*/9	10/1	3/2

IAP, intracisternal A-particle.

One late and one early mutation result in an amino acid change but also affect splicing. Early phenotypes were defined as those identified in the first rounds of screening before 6 months of age, with late phenotypes being those detected after this time.

^*Note that one mutation is the result of a spontaneous IAP insertion that appears to have occurred on the C3H background.