nonnephropathic cystinosis

Nonnephropathic cystinosis, also known as benign or ocular cystinosis, is a milder form of cystinosis. It is an inborn error of metabolism where cystine crystals accumulate in body tissues, primarily affecting the cornea. This accumulation can lead to photophobia, an abnormal sensitivity to bright light.1

Unlike the more severe nephropathic form, nonnephropathic cystinosis does not typically cause significant kidney malfunction or Fanconi syndrome. The condition is linked to mutations in the CTNS gene, which affects the transport of cystine out of cellular lysosomes. Diagnosis is based on symptoms and the detection of cystine crystals in the cornea. Treatment often involves cystine-depleting agents like cysteamine.1