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.