The autosomal recessive lysosomal storage disorder, nephropathic cystinosis is 
characterized by impaired transport of free cystine out of lysosomes. The gene 
responsible for cystinosis, CTNS, consists of 12 exons and encodes a 55 kDa 
putative lysosomal membrane protein, called cystinosin. Up to now more than 55 
different CTNS mutations have been described in cystinosis. We have analyzed the 
mutation pattern in a population of 40 cystinosis patients from 35 families of 
German and Swiss origin. CTNS mutations in 68 out of 70 alleles were identified. 
The common 57-kb deletion accounted for 65% of the alleles. In five patients we 
found a known GACT deletion at position 18-21. In two patients we identified a 
nucleotide substitution at codon 339 and one patient showed a CG insertion at 
position 697-698. In five patients we observed a G insertion at position 
926-927. Moreover, five novel mutations including two deletions involving exon 3 
(61-61+2delGGT) and exon 6 (280delG), two insertions in exon 6 (292-293insA) and 
exon 7 (684insCACTT) and one nucleotide substitution in exon 11 (923G>T) have 
been identified. These data provide a basis for routine molecular diagnosis of 
cystinosis in the central European population, especially in cystinosis patients 
of German and Swiss origin.