Fabry disease (FD), an X-linked lysosomal storage disorder caused by the deficiency of α-galactosidase A, results in the accumulation of globotriaosylceramide and its deacylated derivative globotriaosylsphingosine (lyso-Gb3). Little is known about lyso-Gb3 levels in pediatric population identified through neonatal screening. This study evaluated levels of lyso-Gb3 at birth and during childhood.