Combined Saposin Defiency is a very rare metabolic and genetic disorder that is caused by the mutation in a gene PSAP.

[3] PSAPD is caused by mutations in a PSAP gene, which is located on the long arm of chromosome 10 (10q22.1).

[6] The signs of this disease are respiratory failure, hepatosplenomegaly, poor feeding, myoclonus, hyperkinetic movements, clonic seizures, leukodystrophy, hypotonia, abnormality of eye movement and a neuronal loss.

[8][9] According to one study, Prosaposin might be involved in neuron and glial protection by extracellular secretion and activation of some G protein-coupled receptors.

[6] The study of sphingolipids in urine sediment (It shows combined massive elevation of globotriaosylceramide (Gb3), sulphatide and some other sphingolipids) might be useful for a correct orientation towards diagnosis, also bone marrow/liver’s biopsies usually show Gaucher-like macrophages.