Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a rare autosomal recessive motor neurodegenerative disease and is the leading genetic cause of death among infants and toddlers. PsychoGenics has behaviorally characterized several mouse models of SMA.

The Smn-/-;SMN2;SMNΔ7 neonatal mouse model also referred at Delta 7 is widely used for screening potential therapies. Delta 7 mice have a life span of 17 days with a median survival of 12 days. Rapidly after birth, Delta 7 animals display loss of body weight and motor strength (Figure 1). Due to this rapid symptom progression, PsychoGenics developed motor dysfunction behavioral tests and drug delivery methods to enable treatment as early as birth, including ICV drug administration. In addition, genotyping is performed in less than 24 hours.

Figure 1: Phenotypic assessment of Delta 7 mice. (A) Body weight of Delta 7 mice is significantly lower than their WT control. (B) Kaplan – Meier cumulative survival curves. Delta 7 mice survive for a maximum of 17 days with 50% mortal ity at Post natal day 12. (C) In the Hind Limb Suspension test*, Delta 7 mice exhibit hindlimb weakness and fail to pull themselves out of conical tube compared to their WT littermates. (D) Delta 7 mice fail to right themselves as early as post natal day 6.

All work supported by the SMA Foundation.

* Gogliotti et al, Journal of Neurosciences 2012; Nizzardo et al, Experimental Neurology 2011; Treat – NMD SMA_M.2.2.001 SOP