Used as a biomarker for the diagnosis and monitoring of Fabry disease, a rare genetic disorder caused by the deficiency of alpha-galactosidase A enzyme. Elevated levels of C17 lysosphingomyelin are found in plasma and dried blood spots of affected individuals, making it valuable in newborn screening and differential diagnosis. It helps distinguish Fabry disease from other lysosomal storage disorders and is also used to assess treatment response in patients undergoing enzyme replacement therapy or chaperone therapy.