Infantile nephropathic cystinosis is an autosomal recessivelysosomal storage disease, resulting from intralysosomal cystineaccumulation throughout the whole body due to defective cystine exportas a result of cystinosin defect in the cystine porter. Early symptoms include renal proximal tubulopathy with resultantgrowth failure and progressive decline in glomerular filtration rate thatmay end in renal failure, photophobia, hypothyroidism. CNS symptomsare considered from the long term important complications. Early diagnosis is the first step to achieve successful treatment anddelay the progress of the disease. Treatment falls into two categories:Supportive therapy addressing the enormous loss of fluids & solutes.Specific therapy with cysteamine, an aminothiol, (oral & eye drops),acting through lysosomal cystine depletion.In the current work, intellectual functions and behavioralcharacteristics were assessed for 13 cystinotic patients in addition to brainimaging and auditory function testing as well. We found that cystinosis patients have impaired intellectualfunctions, and behavioral problems as well as brain atrophy of a variabledegree.