Accordingly, developmental and functional defects associated with SMN deficiency have been reported in the autonomic nervous system, liver, lung, intestine, heart, vasculature, bone, endocrine glands1,10,11,13,15,19–24 and, more recently, in the immune system25–27 of SMA patients and animal models. The gene discussed is SMN1; the disease is proximal spinal muscular atrophy.