SMA is an autosomal recessive disorder characterized by progressive muscle weakness secondary to degeneration of anterior horn cells.  SMA is caused by loss of survival motor neuron (SMN) protein, encoded by the SMN1 gene.  SMA is the most common genetic cause of infant mortality worldwide.  Several case reports and animal studies show that SMA is not purely a motor neuron disorder and that cardiac malformations can be a part of the disease.   

Retrospective chart review of six patients with SMA and structural heart malformations, focusing on clinical presentation, disease progression and disease complications.

SMA should be considered in a neonate with structural heart disease who has hypotonia and weakness out of proportion to overall degree of illness.  If SMA is a possibility, this association should be discussed with the cardiology team as it might alter management.  Awareness of the diagnosis of SMA as well as the cardiac disease will allow families to make informed decisions about cardiac surgery and new disease-modifying treatments for SMA.