Introduction: Cystinosis is a rare autosomal recessive lysosomal storage disorder characterized by cystine crystals accumulation in almost all cells and tissues. Patients often develop end organ dysfunction and kidney failure. We aimed to characterize the hematological manifestations and bone marrow involvement in   patients with cytopenia affecting more than one hematologic cell line and to correlate it with patients' growth, thyroid and kidney functions.
Methods: Twenty patients with nephropathic Cystinosis were included. All patients subjected to thorough clinical examination including weight, height standard deviation scores and slit lamp examination for localization and scoring of corneal cystine crystals. Laboratory investigations included renal functions, complete blood count, bone marrow examination for patients with bicytopenia or pancytopenia.
Results: Sixteen cases (80%) had anemia. A significantly higher CCC score, creatinine level, ferritin level and a lower thyroid function level were found in the anemic group of patients (p= 0.044, 0.016, 0.022 and 0.016 respectively) compared to the non anemic group. Three patients (15%) experienced cytopenia in more than lineage, bone marrow examination showed cystine crystal deposition, normal bone marrow cellularity with trilineage hematopoiesis.
Conclusion: Cystinosis patients experienced hematological complications, anemia was present in most of the patients, patients with hypothyroidism and higher corneal crystals depositions had lower hemoglobin level, so these patients need monitoring of their blood count. Although cystine crystals were seen in the bone marrow of our cases, cytopenia and hematological symptoms were not attributed to bone marrow suppression by cystine crystals deposition. Various other etiologies should be thoroughly investigated.