Two rare genetic diseases of the [gamma]-glutamyl cycle, glutathione synthetase deficiency and 5-oxoprolinase deficiency, that have been described lead to the accumulation of 5-oxoproline in plasma and urine (3).
Two genetic deficiencies of the [gamma]-glutamyl cycle, glutathione synthetase deficiency and 5-oxoprolinase deficiency (3), lead to very large increases in 5-oxoproline excretion.
Finally, a previous investigation of another subject with acute onset 5-oxoprolinuria yielded normal activities of glutathione synthetase and 5-oxoprolinase (1).
Such rare defects or deficiencies have been described for most of the enzymes involved in the cycle, but those involving glutathione synthetase and 5-oxoprolinase are of particular clinical interest.
An inborn defect in the enzyme 5-oxoprolinase was first described in 1981 in two brothers, ages 11 and 16 years .
This case is similar to a previous case of transient 5-oxoprolinuria reported in 1989 , where the source of the metabolite accumulation was suggested to be attributable to an acquired deficiency of glutathione synthetase or 5-oxoprolinase activity, gastrointestinal absorption of 5-oxoproline from an unidentified dietary source, or some combination of these factors.
In addition, we further hypothesize that such a disturbance in the [gamma]-glutamyl cycle was a direct result of the action of flucloxacillin, netilmicin, or the combination of both on the activity of 5-oxoprolinase.