[Cysteamine in the treatment of cystinosis in children. In vitro and in vivo studies].

The effect of cysteamine was studied in 6 children with nephropathic cystinosis. In 3 of them an in vitro study on fibroblasts was performed. The cystine content of fibroblasts was immediately diminished (about 90% of total cystine content) as soon as the concentration of cysteamine in the medium was greater than or equal to 0,1 mmole/l. In vivo, 50 to 89 mg/kg/day of cysteamine was administered for 9 to 37 months (mean 21,3). There was no adverse reaction. In all cases a dramatic decline in leukocyte cystine level was observed (in 5 cases the level was within the range seen in clinically unaffected heterozygotes). Growth was not improved. The renal function was stabilised in 3 cases. Photophobia which was present in 4 children decreased in 2 cases or disappeared in 2 cases.