Cystinosis

This code identifies cystinosis, a rare, inherited metabolic disorder characterized by the abnormal accumulation of the amino acid cystine within lysosomes in various organs and tissues. This accumulation leads to progressive organ damage, particularly affecting the kidneys, eyes, and thyroid gland.

Use this code for patients diagnosed with any form of cystinosis, including nephropathic, intermediate, or ocular non-nephropathic types. Documentation should clearly state the diagnosis of cystinosis, often supported by genetic testing, cystine crystal detection in the cornea, or elevated leukocyte cystine levels.

• Do not code this with E72.09 (Fanconi syndrome without cystinosis) as per the Excludes1 note.
• Specify the type of cystinosis (e.g., infantile nephropathic, adolescent nephropathic, adult non-nephropathic) if documented, although this code encompasses all forms.
• Code any associated manifestations or complications, such as chronic kidney disease, hypothyroidism, or ocular complications, as secondary diagnoses.