Blood Flow to the Spleen is Altered in a Mouse Model of Spinal Muscular Atrophy.

Spinal muscular atrophy (SMA) is a neuromuscular disorder affecting young children. While pre-clinical models of SMA show small spleens, the same is not true in humans. Here, we show by doppler ultrasonography decreased splenic blood flow in Smn2B/- mice. Further, AAV9-SMN gene therapy does not rescue the distal ear and tail necrosis nor the spleen size in these mice, suggesting that the latter is linked to a cardiovascular defect. Absence of smaller spleens in human patients is likely due to differences in presentation of defects in SMA between pre-clinical mouse models and human patients, particularly the susceptibility to cardiovascular issues.