OBJECTIVE: Nephropathic cystinosis is an autosomal recessive lysosomal storage 
disorder that is characterised by the accumulation of the amino acid cystine in 
several body tissues due to a mutation in the CTNS gene, which encodes the 
cystinosin protein. The aim of this study was to sequence the coding exons of 
the CTNS gene in five different Jordanian families and one family from Sudan 
with nephropathic cystinosis.
METHODS: Probands initially presented with Fanconi syndrome symptoms. An eye 
examination showed the accumulation of cystine crystals in the cornea by the age 
of 2 years, suggesting cystinosis. All of the coding exons and flanking intronic 
sequences and the promoter region of the CTNS gene were amplified using 
polymerase chain reaction and subjected to sequencing.
RESULTS: None of the probands in this study carried the European 57-kb deletion 
in the CTNS gene. Seven variants in the coding and promoter sequence of the CTNS 
gene were identified in the probands of this study. Two of these variants were a 
CTNS mutation that was previously identified in a heterozygous genotype in two 
different patients of European descendant. The two mutations were c.829dupA in 
exon 10 and c.890G>A in exon 11. The proband of family 2 was 
compound-heterozygous for the two mutations.
CONCLUSION: This study is the first molecular study of infantile nephropathic 
cystinosis in Jordan. We successfully identified the causative CTNS mutations in 
Jordanian families. The results provide a basis for the early detection of the 
disease using molecular tools in a highly consanguineous Jordanian population.