Plasma amyloid beta measurements - a desired but elusive Alzheimer's disease biomarker

Table 1 Cross-sectional studies in populations including Down syndrome and familial Alzheimer's disease due to trisomy 21 or autosomal dominant mutations, respectively

					Values in DS patients compared to controls			Values in dDS compared to cnDS
Study	Subjects	Mean age (years)	Platform and antibodies	%CV	Aβ_1-40	Aβ_1-42	Aβ_1-42/Aβ_1-40	Aβ_1-40	Aβ_1-42	Aβ_1-42/Aβ_1-40
Schupf et al. 2001 [52]	97 cnDS	51.9	ELISA	-	↑	↑	-	=	↑	-
	11 dDS	56	6E10
			R182
			R165
Schupf et al. 2007 [32]			ELISA	-	-	-	-	=	↑	-
			6E10
			R182
			R165
Matsuoka et al. 2009 [53]	148 cnDS	54.2	ELISA	<11.0%	-	-	-	=	=	↑
	52 dDS	56.0	82E1
			1A10
			1C3
Prasher et al. 2010 [35]	83 cnDS	49.0	ELISA	-	-	-	- =	= =		a
	52dDS	56.8	6E10
			R182
			R165
Head et al. 2011 [34]	11 yCN	46.5	ELISA	-	↑	↑	=	-	-	-
	12 aCN	74.2	Wako
	17 AD	75.3
	43 cnDS	45
	52 dDS	53.3
Coppus et al. 2012 [54]	62 dDS	54	xMAP	-	-	-	-	↑	=	=
	264 cnDS	50.6	INNO-BIA
Reiman et al. 2012 [51]	10 PSEN1+ CN	23	xMAP	-	-	-	-	-	-	-
	10 PSEN1- CN	24	INNO-BIA

^adDS who had a dementia history of 4 or more years had increased Aβ_1-42/Aβ_1-40 compared with dDS with a more recent diagnosis. aCN, aged cognitively normal controls; AD, Alzheimer's disease; CN, cognitively normal; cnDS, cognitively normal Down syndrome; CV, coefficient of variation; dDS, demented Down syndrome; DS, Down syndrome; yCN, young cognitively normal controls.