TABLE 4.

APOE allele characteristics (A) and APOE ε4 carrier status and age at onset (B) of the cognitively normal, early-onset Alzheimer's disease, and early-onset non-Alzheimer's disease groups.

A.	CN	EOAD	EOnonAD	EOAD versus CN	EOnonAD versus CN	EOAD versus EOnonAD
N	89	212	70
ε2 Heterozygous	7.9%	4.7%	11.4%	0.28	0.45	0.05
ε4 Heterozygous	41.6%	53.8%	41.4%	0.05	0.98	0.07
ε4 Homozygous	9.0%	14.2%	2.9%	0.22	0.11	0.01
B.	EOAD		EOnonAD		Combined
	APOE ε4−	APOE ε4+	APOE ε4−	APOE ε4+	APOE ε4−	APOE ε4+
N	98	114	41	29	139	143
Age at onset	54.82 (4.3)	55.81 (4.3)	54.7 (5.8)	55.64 (5.0)	54.79 (4.7)	55.77 (4.4)
Comparison of +/− within Groups	p = 0.11		p = 0.88		p = 0.08
Comparison of + and − between groups					0.91	0.49

Note: A. Values represent % of CN, EOAD, and EOnonAD samples with the respective allele characteristics. EOAD versus CN, EOnonAD versus CN, and EOAD versus EOnonAD represent p values from the post hoc analyses comparing the respective groups following significant ANOVA analysis. B. APOE ε4 represents the absence of an ε4 allele, and APOE ε4+ represents the presence of an ε4 allele. Age at onset represented by age (SD). Comparison of +/− within groups represents results of t-tests comparing age at onset between APOE ε4- and ε4+ carriers within EOAD, EOnonAD, and combined groups. Comparison of + and − between groups represents results of t-tests comparing age at onset of APOE e4- participants between EOAD and EOnonAD groups, and age at onset of APOE ε4+ participants between EOAD and EOnonAD groups.

Abbreviations: APOE, apolipoprotein E; CN, cognitively normal; EOAD, early-onset Alzheimer's disease; EOnonAD, early-onset non-Alzheimer's disease.