What maternal disease is most likely to cause hypertrophic cardiomyopathy (HCM) in a neonate, considering Systemic Lupus Erythematosus (SLE), Diabetes Mellitus (DM), Graves' disease, and glycogen storage disease?

Maternal Diabetes Mellitus Causes Neonatal Hypertrophic Cardiomyopathy

Maternal diabetes mellitus (both pregestational type 1 and type 2, as well as gestational diabetes) is the maternal disease that causes transient hypertrophic cardiomyopathy in neonates. 1, 2

Why Diabetes Mellitus is the Answer

• Maternal hyperglycemia has a direct pathophysiologic effect on the fetal myocardium, causing a unique form of transient ventricular hypertrophy that develops in late gestation 1, 2
• This occurs even with good diabetic control during pregnancy, though severity is reduced with careful glycemic management 1, 3
• The hypertrophy typically involves the interventricular septum and is the most common cardiac finding in infants of diabetic mothers, occurring in 38% of cases 4

Clinical Characteristics of Diabetic-Associated Neonatal HCM

• The condition is usually transient and benign, resolving spontaneously over weeks to months after birth 3
• Severity ranges from incidental echocardiographic findings to severe congestive heart failure requiring supportive therapy 3
• In rare cases, severe hypertrophic cardiomyopathy can cause hydrops fetalis and fetal death, even with well-controlled maternal diabetes 5
• Fetal echocardiography is recommended as part of prenatal screening in diabetic pregnancies to monitor for this complication 1

Why the Other Options Are Incorrect

Systemic Lupus Erythematosus (SLE)

• SLE does not cause neonatal hypertrophic cardiomyopathy 1
• SLE-related cardiac effects in neonates involve congenital heart block from transplacental antibody passage, not myocardial hypertrophy

Graves' Disease

• Graves' disease is not associated with neonatal hypertrophic cardiomyopathy 1
• While maternal hyperthyroidism can affect the fetus, it does not produce the characteristic septal hypertrophy seen with maternal diabetes

Glycogen Storage Disease

• This is a critical distinction: glycogen storage diseases (such as Pompe disease and Danon disease) are genetic metabolic disorders of the infant itself, not maternal conditions 1, 2
• These are inherited conditions that cause HCM in the affected child due to abnormal glycogen metabolism in the child's own myocardium 1
• The question specifically asks about maternal disease causing neonatal HCM, making this option incorrect by definition

Clinical Implications

• All infants of diabetic mothers should undergo echocardiographic screening to detect hypertrophic cardiomyopathy and other cardiac anomalies 4, 6
• The overall incidence of congenital heart disease in infants of diabetic mothers is 15% (excluding patent ductus arteriosus and hypertrophic cardiomyopathy) 4
• Careful diabetic management during pregnancy significantly reduces the severity of hypertrophic cardiomyopathy, though mild generalized hypertrophy may still occur 3
• Monitoring fetal heart function is particularly important in macrosomic fetuses of diabetic mothers, as severe cardiomyopathy may explain otherwise unexplained fetal deaths 5