Table 1. Plasma lyso-GM2 levels and hexosaminidase activities.

Disease	Case	Age	Sex	MUG-degrading activity (nmol/h/mL)	MUGS-degrading activity (nmol/h/mL)	Lyso-GM2 (nmol/L)	Reference
Sandhoff disease	Patient 1	1 y	M	17	5	12.7	[9]
	Patient 2	31 y	M	42	5	2.9	[10]
	Parent 1-1	unknown	M	309	34	<2.0	-
	Parent 1-2	unknown	F	357	41	<2.0	-
Tay-Sachs disease	Patient 3	1 y	F	552	2	39.9	-
	Patient 4	1 y	F	533	2	29.7	-
	Patient 5	1 y	M	382	2	26.4	-
	Patient 6	1 y	M	494	2	30.1	-
	Patient 7	2 y	M	281	1	32.6	-
	Parent 3-1	31 y	M	542	27	<2.0	-
	Parent 3-2	33 y	F	513	31	<2.0
	Parent 4-1	unknown	M	347	30	<2.0	-
	Parent 4-2	unknown	F	478	26	<2.0	-
	Parent 5-1	31 y	F	1.12×103	35	<2.0	-
GM2A deficiency	Patient 8	1 y	M	1.42×103	81	<2.0	[11]
Control (n = 48)			M/F	709±302	58±14	<2.0

Patient 1, and parents 1-1 and 1-2 are from the same family; patient 3, and parents 3-1 and 3-2 are from the same family; patient 4, and parents 4-1 and 4-2 are from the same family; and patient 5, and parent 5-1 are from the same family.