[Importance of lysosomal storage diseases in rheumatology].

Lysosomal storage diseases are a group of rare hereditary metabolic diseases. Due to a deficiency of lysosomal enzymes, complex substrates accumulate in the lysosomes of various organs. Depending on the affected enzyme, this results in clinically variable and chronic progressive multiorgan diseases. Diagnosis is often delayed. As clinical symptoms include the musculoskeletal system, an awareness of lysosomal storage diseases is of relevance to (pediatric) rheumatologists. This article is focused on Mucopolysaccharidosis type I‑S, Mucolipidosis type III, Gaucher disease and Fabry disease. When suspecting a lysosomal storage disease, enzyme activity should be determined in dried blood spots or leukocytes. For some diseases, specific biomarkers can additionally be analyzed. Diagnosis should be confirmed by genetic testing. As causal treatment options are available for three of the presented diseases, a timely diagnosis is very important.