PT  - JOURNAL ARTICLE
AU  - Bernal, S
AU  - Alías, L
AU  - Barceló, M J
AU  - Also-Rallo, E
AU  - Martínez-Hernández, R
AU  - Gámez, J
AU  - Guillén-Navarro, E
AU  - Rosell, J
AU  - Hernando, I
AU  - Rodríguez-Alvarez, F J
AU  - Borrego, S
AU  - Millán, J M
AU  - Hernández-Chico, C
AU  - Baiget, M
AU  - Fuentes-Prior, P
AU  - Tizzano, E F
TI  - The c.859G>C variant in the <em>SMN2</em> gene is associated with types II and III SMA and originates from a common ancestor
AID  - 10.1136/jmg.2010.079004
DP  - 2010 Sep 01
TA  - Journal of Medical Genetics
PG  - 640--642
VI  - 47
IP  - 9
4099  - http://jmg.bmj.com/content/47/9/640.short
4100  - http://jmg.bmj.com/content/47/9/640.full
SO  - J Med Genet2010 Sep 01; 47
AB  - Homozygous mutations of the telomeric SMN1 gene lead to degeneration of motor neurons causing spinal muscular atrophy (SMA). A highly similar centromeric gene (SMN2) can only partially compensate for SMN1 deficiency. The c.859G>C variant in SMN2 has been recently reported as a positive disease modifier. We identified the variant in 10 unrelated chronic SMA patients with a wide spectrum of phenotypes ranging from type II patients who can only sit to adult walkers. Haplotype analysis strongly suggests that the variant originated from a common ancestor. Our results confirm that the c.859G>C variant is a milder SMN2 allele and predict a direct correlation between SMN activity and phenotypic severity.