A Retrospective Chart Review Study on the Burden of Illness of Acid Sphingomyelinase Deficiency in Brazil

<b>Background</b>: Acid sphingomyelinase deficiency (ASMD) is a rare, progressive lysosomal storage disease with heterogeneous clinical manifestations. Evidence on the disease burden of ASMD is limited in Brazil. <b>Methods</b>: This observational, multicenter, retrospective study assessed the characteristics and clinical data of patients with ASMD type B and type A/B. Patients' demographic data were retrieved from Hospital de Clínicas de Porto Alegre between January 1, 1986 and May 31, 2021, and available medical records were collected from eight centers in Brazil. <b>Results</b>: The study included 124 patients (full cohort: ASMD type B [75.8%] and type A/B [24.2%]; median [interquartile range {IQR}] age: 10.0 [3.6-19.9] years at diagnosis, <i>n</i> = 94), while medical records were available for 24 patients (subset cohort: ASMD type B [87.5%] and type A/B [12.5%]; median [IQR] age: 6.7 [1.9-11.3] years at diagnosis). Hepatobiliary and splenic manifestations were the most common clinical findings at symptom onset/diagnosis (75.0% and 70.8%, respectively) and at the last follow-up/death (83.3% each), with the majority of patients showing abnormal liver function parameters at both time points. At least 50.0% of patients had comorbidities at symptom onset or diagnosis. The incidence of hospitalization was reported in 33.3% patients at symptom onset/diagnosis and in 45.9% at the last follow-up/death. During the follow-up period, two patients with ASMD type A/B died in the subset cohort. <b>Conclusions</b>: The study provides insights into the high burden of illness in patients with ASMD, highlighting the need for disease awareness and early diagnosis in Brazil.