The baseline 12‑lead ECG demonstrated a short PR interval with a delta wave and markedly increased QRS voltages consistent with LVH. The presence of unexplained LVH commonly suggests HCM1, a sarcomeric protein gene disorder. However, ventricular preexcitation—while sometimes observed in HCM [1]—should prompt consideration of HCM phenocopies, particularly storage, metabolic, or syndromic conditions [[1], [2], [3], [4]].

Among metabolic storage disorders associated with severe LVH, the most