Saccharopinuria (an excess of saccharopine in the urine), also called saccharopinemia, saccharopine dehydrogenase deficiency or alpha-aminoadipic semialdehyde synthase deficiency, is a variant form of hyperlysinemia. It is caused by a partial deficiency of the enzyme saccharopine dehydrogenase, which plays a secondary role in the lysine metabolic pathway. Inheritance is thought to be autosomal recessive, but this cannot be established as individuals affected by saccharopinuria typically have only a 40% reduction in functional enzyme. See also
Hyperlysinemia

References
External links
Saccharopinuria; Alpha-aminoadipic semialdehyde synthase deficiency at NIHs Office of Rare Diseases
Overall, metastases have or will develop in up to 40% of individuals with UPS. These metastases are reported to occur in lung (40% to 55% of cases) and less commonly in other sites such as lymph nodes near the primary tumor, brain, pancreas, and heart. Neoplastic Fever
A review study conducted in China of 183 individuals with UPS reported that 7 (3.83%) individuals (age 51 to 73 years; median age 62.8 years) had a subtype of the paraneoplastic syndrome termed neoplastic fever, i.e. these individuals suffered continuous, disabling fevers. Their tumors  were located within a thigh muscle (4 cases), the upper arm (2 cases), or the lower leg (1 case). Compared to 89 individuals (median age 59.1 years) with a similar distribution of their UPS tumors, individuals with the neoplastic syndrome had similar tumor recurrence rates (57.14% vs 53.93% for the two respective groups) but a lower metastasis rate (14.29% vs 44.94%) and a higher 3-year survival rate (85.71% vs 59.55%). Fever symptoms disappeared in all patients after surgical removal of their tumors. It is suggested that individuals with UPS and neoplastic fever have a more favorable prognosis than individuals with UPS that do not evidence such fevers. Pathology
UPS is a diagnosis of exclusion (a diagnosis reached by the process of elimination) because the histopathology of this disorders tumors is non-specific. UPS tumor cells are undifferentiated (i.e. do not resemble any particular cell type) and pleomorphic (i.e. highly variable in size, shape, and/or color) when examined microscopically.