The History of Cystinosis: Lessons for Clinical Management

Figure 4

Leukocyte monitoring of leukocyte cystine levels in 50 Canadian children with nephropathic cystinosis. Introduction of oral cysteamine therapy (1.3 g/m²/day in four divided doses) in early childhood achieves a rapid reduction of trough 6–8 hours after a single dose. Following a variable “honeymoon period,” mean leukocyte cystine gradually drifts upwards as compliance decreases. Cystine levels return to baseline when stopped briefly for transplant or when teenagers discontinue therapy.