Gamma-Glutamyl Transpeptidase Deficiency
A disorder that is characterized by increased glutathione concentration in the plasma and urine.
Epidemiology
Gamma-glutamyl transpeptidase deficiency has been detected in seven patients in five families worldwide.
Clinical description
Five of the patients also had central nervous system involvement.
Etiology
Gamma-glutamyl transpeptidase catalyses the first step in the degradation of glutathione. No mutations have been identified in patients with gamma-glutamyl transpeptidase deficiency.
Diagnostic methods
The diagnosis is based on the finding of glutathionuria, elevated levels of glutathione in plasma and decreased activity of gamma-glutamyl transpeptidase in nucleated cells.
Genetic counseling
As the disease is transmitted as an autosomal recessive trait, patients should be offered genetic counseling.
Management and treatment
No specific treatment has been proposed or tested.
Prognosis
The prognosis of gamma-glutamyl transpeptidase deficiency is hard to predict as only seven patients have been described worldwide.