Elevated Troponin in an Infant With Spinal Muscular Atrophy

Abstract

Spinal muscular atrophy (SMA) is a progressive neuromuscular disorder caused by mutations in the SMN1 gene, leading to motor neuron degeneration. This report presents a case of a 22-day-old infant with spinal muscular atrophy who was found to have elevated troponin I level in preparation for administration of a gene therapy with known cardiac adverse effects. Although initial echocardiogram revealed a left-ventricular ejection fraction of 57% at 22 days old, subsequent comprehensive cardiac evaluation revealed improving troponin I levels with a normal left-ventricular ejection fraction of 70% at 34 days of life prior to starting gene therapy. Although not common, elevated troponin I level in an otherwise asymptomatic newborn can be seen in spinal muscular atrophy. This case underscores that elevated troponins may be intrinsic to newborns with spinal muscular atrophy even before starting therapies for spinal muscular atrophy. In addition, we illustrate no further cardiac abnormalities after infusion of the aforementioned gene therapy in a child with asymptomatic elevated troponin I after cardiac clearance.