A mutation in the saposin A domain of the sphingolipid activator protein (prosaposin) gene results in a late-onset, chronic form of globoid cell leukodystrophy in the mouse.
The recently developed saposin A-/- mice showed a chronic form of globoid cell leukodystrophy, establishing the essential in vivo role of saposin A as an activator for galactosylceramidase to degrade galactosylceramide.
We present this case to add to the literature on the rare diagnosis of atypical Krabbe disease due to saposin A deficiency, to report a novel presumed pathogenic variant within PSAP, and to suggest that individuals with saposin A deficiency may have elevated levels of psychosine, similar to children with classic Krabbe disease due to GALC deficiency.
Recently, deficiency of one of the sphingolipid activator proteins, saposin A, was demonstrated to cause a late-onset, slowly progressive globoid cell leukodystrophy at least in the mouse, with all of the phenotypic consequences of impaired degradation of galactosylceramidase substrates.
A mutation in the saposin A coding region of the prosaposin gene in an infant presenting as Krabbe disease: first report of saposin A deficiency in humans.
A mutation in the saposin A domain of the sphingolipid activator protein (prosaposin) gene results in a late-onset, chronic form of globoid cell leukodystrophy in the mouse.
The patient's phenotype depends then on the nature of the second allele - atypical Gaucher disease in case of saposin A, MLD in case of saposin B, and Krabbe disease in case of saposin C impairing mutations.