Potential Mechanisms of Platelet Dysfunction and Bleeding in Acid Sphingomyelinase Deficiency

Acid sphingomyelinase deficiency (ASMD) is an autosomal recessive lysosomal storage disorder caused by mutations in the SMPD1 gene, resulting in sphingomyelin accumulation. With a birth prevalence of 0.25-0.6 per 100,000, it is more prevalent in Ashkenazi Jewish and Middle Eastern populations. The disease features a clinical spectrum ranging from severe, early-onset neurodegeneration (infantile neurovisceral ASMD) to chronic, non-neurological visceral involvement (chronic visceral ASMD) and intermediate forms (chronic neurovisceral ASMD). The chronic visceral form is characterized by liver dysfunction, respiratory symptoms, and hepatosplenomegaly, which can lead to secondary thrombocytopenia. The majority of patients exhibit thrombocytopenia and/or mild bleeding manifestations, most commonly easy bruising and epistaxis, whereas clinically significant bleeding events, including gastrointestinal or variceal hemorrhage, occur less frequently. Systematic platelet-function studies in patients with ASMD are currently lacking. Evidence retrieved from biological models indicates that ASMD contributes to platelet dysfunction, including impaired secretion and thrombin generation, mediated by complex pathological mechanisms. These findings underscore the importance of hematological monitoring and further research in patients with this condition and could potentially offer new therapeutic possibilities.