Fetal Dilated Cardiomyopathy Associated With Variants of Uncertain Significance in MYH7 and DSG2 Genes: A Case Report and Review of the Literature

Background: Fetal dilated cardiomyopathy (DCM) is an uncommon prenatal diagnosis associated with significant morbidity and mortality. Case: This report describes a patient with a diagnosis of fetal DCM at 310 weeks gestation, several weeks after a maternal flu-like illness. Spontaneous improvement was noted on serial echocardiograms. Maternal Coxsackievirus B titers were significantly elevated at 1:80, although post-natal cord blood test results were negative. Genetic panel testing for DCM demonstrated two heterozygous variants of uncertain significance in the MYH7 and DSG2 genes. Although an early post-natal echocardiogram demonstrated a normal left ventricular ejection fraction, right ventricular dysfunction was noted with subsequent cardiac decompensation requiring temporary inotropic support. An echocardiogram at the age of 2 years confirmed normal biventricular function. Conclusion: The finding of fetal DCM should trigger a broad evaluation. In the setting of limited fetal cardiac reserve, the significant hemodynamic changes that occur post-natally may trigger additional decompensation. Clinicians should be aware of the prognostic value of right ventricular function, as measured by fractional area change, in addition to the limitations of serologic and genetic testing.