Multisystemic smooth muscle dysfunction syndrome (MSMDS) is a rare genetic disorder with a prevalence of less than 1 in 1,000,000 (Orphanet 2024). A mutation in the ACTA2 gene disrupts the function of smooth muscle cells, affecting organs reliant on smooth muscle cell activity, particularly the vasculature. MSMDS impacts multiple organ systems, including the ocular, cardiovascular, respiratory, cerebrovascular, gastrointestinal, and genitourinary. Some manifestations are evident at birth, while others emerge as the patient ages. For instance, fixed dilated pupils (Fig. 1), which are reported to have full penetrance, can be observed after birth. Additionally, failure of the ductus arteriosus to close, a condition reported in most patients, typically presents early in infancy. Conversely, certain complications, such as thoracic aortic aneurysm and cerebrovascular issues (Fig. 2), develop over time (Milewicz et al. 2010).