Table 1.

Properties of missense mutations in SMA patients.

Mutation	Position of mutation		SMA type	SMN2 copy number	Ability to Rescue mouse or fish SMA models	Ability to bind SMN	Ability to bind Sm proteins	Ability to Assemble snRNP when low amounts of non mutant SMN are present	References
	Exon	Domain
A2G	1	ND	III	1	High	(++)	(++)	(++)	98, 103, 104
D30N	2a	Gemin2	II	2	ND	(+++)	(+++)	(+++)	47, 96
D44V	2a	Gemin2	III	1	ND	(+++)	(+++)	(++)	96,99
W92S	3	Tudor	I	3	ND	ND	(+)	ND	100
V94G	3	Tudor	II	3	ND	ND	ND	ND	101
G95R	3	Tudor	III	1	ND	(+++)	(+++)	ND	96
A111G	3	Tudor	Ib	2	High	(+++)	(+++)	(+++)40, 47	40, 47 96, 123
I116F	3	Tudor	Ib	2	ND	ND	ND	(+)	47, 102
Y130C	3	Tudor	III	2	ND	ND	ND	ND	163
E134K	3	Tudor	I	2	ND	(+++)	(+)#	(+)	47, 96, 97
Q136E	3	Tudor	I	1	ND	ND	ND	(+)	47, 102
A188S	4	ND	I	ND	ND	ND	ND	ND	164
P245L	6	oligomer	III	ND	ND	ND	ND	ND	165
L260S	6	oligomer	II	2	ND	ND	ND	ND	101
S262G	6	oligomer	III	1	ND	ND	ND	ND	96
S262I	6	oligomer	III	1	ND	(++)	(++)	ND	36, 166
M263R	6	oligomer	I	2	ND	ND	ND	ND	101
M263T	6	oligomer	II	1	ND	ND	ND	ND	95
S266P	6	oligomer	II	2	ND	ND	ND	ND	163
Y272C*	6	oligomer	II	2	No	(+)	(+)	(+)	36, 47, 123, 166
H273R	6	oligomer	II	ND	ND	ND	ND	ND	163
T274I	6	oligomer	III	1	ND	(++)	(++)	(+++)	36, 47, 166
G275S	6	oligomer	III	ND	ND	ND	ND	ND	101
G279C	7	oligomer	I	ND	ND	ND	ND	ND	167
G279V	7	oligomer	I	ND	No	(+)	(+)	(+)	36, 47, 123, 162

^*The SMNY272C mutation has been reported in all three types of SMA with severity of the phenotype being dependent on SMN2 copy number. This mutant SMN does not oligomerize efficiently and is rapidly turned over. SnRNP assembly has been assayed in mouse spinal cord tissue for SMNA2G and SMNA111G and in cell culture in all other cases indicated.⁴⁷

⁺low binding or low activity;

⁺⁺moderate binding or activity;

⁺⁺⁺high binding or activity ND is not determined.

^#Sm binding assay performed with just the Tudor domain of SMN and not full-length SMN.