Table 1

Causes of 5-oxoprolinuria beside glutathione synthetase deficiency and 5-oxoprolinase deficiency.

Etiology
Possible mechanism
Ref.

Diet
Certain infant formulas and tomato juice may contain proteins modified by preparation that have increased 5-oxoproline content
[52]
Severe burns Stevens-Johnson syndrome
Increased metabolism of collagen, fibrinogen or other proteins that contain substantial amounts of 5-oxoproline
[53]
Other inborn errors of metabolism
Inborn errors of metabolism not involving the gamma-glutamyl cycle, e.g. X-linked ornithine trancarbamylase deficiency, urea cycle defects, tyrosinemia. In critical organs (e.g. liver, kidney), lack of ATP, which is needed for conversion of 5-oxoproline into glutamate, may lead to 5-oxoprolinuria
[29] [9]
Homocystinuria
Patients with homocystinuria may have excessive formation of 5-oxoproline
[54]
Drug metabolism
Paracetamol, vigabatrin and antibiotics (flucloxacillin, netimicin) probably interact with the gamma-glutamyl cycle
[55-57]
Prematurity
Transient 5-oxoprolinuria has been observed in very preterm infants. The cause is unknown
[58] [29, 59]
Malnutrition, pregnancy
Limited availability of glycine
[60]
Nephropatic cystinosis
Nephropatic cystinosis patients: may have 5-oxoprolinuria probably because of decreased availability of free cysteine, resulting in a secondary impairment of the γ-glutamyl cycle. Cysteamine therapy normalizes the 5-oxoprolinuria
[61]

Ristoff and Larsson Orphanet Journal of Rare Diseases 2007 2:16   doi:10.1186/1750-1172-2-16