Trial on Treatment of Patients With Primary Hyperoxaluria Type I With Pyridoxal-phosphate

In this study the investigators will prospectively analyze the reduction of urinary oxalate excretion under the treatment with PLP in dosages of 5mg/kg/day up to 20 mg/kg/day and serum level response relationship with PLP as an i.v. solution used orally in 12 patients with primary hyperoxaluria type I as an inherited autosomal-recessive-disorder leading to increased endogenous oxalate production, urolithiasis and end stage renal disease.