Advanced strategies for detecting acid sphingomyelinase deficiency type B with attenuated phenotypes.

Background: Acid Sphingomyelinase Deficiency (ASMD) type B is a rare lysosomal disorder caused by SMPD1 mutations. Due to its low prevalence and clinical heterogeneity, diagnosis is challenging, and detection is crucial for the initiation of enzyme replacement therapy.

Methods: We conducted a retrospective study (RnIPH 2024-85) at Toulouse University Hospital, analyzing 359,802 lipid profiles (2012-2023). We identified individuals with a total cholesterol/HDL cholesterol ratio > 4.5. A regex-based extraction method screened records for consanguinity, hepatomegaly, splenomegaly, and ground-glass opacities (GGOs), while we also analyzed thrombocytopenia (< 150 × 10⁹/L). Patients meeting ≥ 4/5 criteria underwent clinical review.

Results: Among 63,653 patients with dyslipidemia, 20.3% had thrombocytopenia, 4.93% hepatosplenomegaly, 2.29% GGOs, and 0.24% consanguinity. In total, 179 patients met ≥ 4/5 criteria. Nineteen (10.6%) were pediatric. Three previously diagnosed ASMD type B patients in our center were identified. Additionally, among other conditions, 46 cases (25.7%) had monogenic diseases, and five undiagnosed patients were flagged for ASMD screening.

Conclusion: Our hybrid screening effectively identified ASMD type B cases and potential candidates for genetic testing. This approach combining algorithmic filtering and clinical expertise, could enhance ASMD type B diagnosis.