Laboratory-Positive Findings for Six Lysosomal Storage Disorders in Pediatric Dried Blood Spot Samples from Uzbekistan: A 2025 Retrospective Descriptive Study

Lysosomal storage disorders (LSDs) are genetically and clinically heterogeneous conditions in which delayed recognition may permit irreversible multisystem injury. Flow-injection analysis tandem mass spectrometry (FIA-MS/MS) of dried blood spots (DBS) provides a practical first-tier approach for multiplex lysosomal enzyme measurement. We performed a retrospective descriptive analysis of 14,989 valid unique pediatric DBS sample records from 13 geographic categories in Uzbekistan during 2025 after exclusion of technical/non-interpretable entries and duplicate plate identifiers. Of these, 386 samples were laboratory-positive (2.58%). Pompe disease was the most frequent category (141/386, 36.5%), followed by Krabbe disease (105/386, 27.2%), Gaucher disease (76/386, 19.7%), acid sphingomyelinase deficiency/Niemann-Pick disease type A/B (48/386, 12.4%), Fabry disease (10/386, 2.6%), and mucopolysaccharidosis type I (MPS I) based on reduced α-L-iduronidase (IDUA) activity (6/386, 1.6%). Regional sample denominators were available for all 13 geographic categories; the highest laboratory-positive proportion was observed in Surkhandarya (42/570; 7.37%), followed by Samarkand (87/2604; 3.34%), Kashkadarya (70/2152; 3.25%), and Khorezm (44/1366; 3.22%). Among the laboratory-positive samples, median first-tier activities corresponded to 80.5% for acid β-glucocerebrosidase (ABG), 79.6% for acid sphingomyelinase (ASM), 81.6% for acid α-glucosidase (GAA), 68.3% for galactocerebrosidase (GALC), 53.5% for α-galactosidase A (GLA), and 15.5% for IDUA relative to the respective decision limits. These results represent first-tier laboratory-positive signals in a selectively tested sample cohort rather than confirmed diagnoses or population incidence/prevalence. Systematic biochemical and molecular confirmation, patient-level linkage, and analytical batch review are required for definitive interpretation.