title: Lysosomal cystine transport in cystinosis variants and their parents.
abstract: Children with nephropathic cystinosis store 50 to 100 times normal amounts of free cystine in many cells and display negligible lysosomal cystine transport in their leucocytes and cultured fibroblasts. A patient with intermediate (adolescent) cystinosis exhibited a similar deficiency of egress out of fibroblast lysosome-rich granular fractions. Another individual with benign (adult) cystinosis accumulated only 2.85 nmol 1/2 cystine/mg leucocyte protein, or 20-50% of the amount stored in nephropathic cystinosis leucocytes. His leucocyte granular fractions also displayed substantial residual cystine-carrying capacity, as determined by measurement of lysosomal cystine counter-transport. We conclude that the variant forms of cystinosis represent a continuum of lysosomal cystine storage, with the varied clinical presentation depending on the amount of residual cystine-carrying capacity, genetic predispositions, and differential tissue susceptibilities.
mesh_terms: D000328:Adult; D003553:Cystine / Q000378:metabolism*; D003554:Cystinosis / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000032:analysis; D006801:Humans; D007962:Leukocytes / Q000032:analysis; D008247:Lysosomes / Q000378:metabolism*; D008297:Male
chemical_list: D003553:Cystine