Native kidney and graft survival in a cohort of Egyptian children with nephropathic cystinosis: national referral center experience

BACKGROUND: Nephropathic Cystinosis is a rare autosomal recessive lysosomal storage disorder. In addition to kidney dysfunction, this disorder can also affect other organs, such as the eyes, thyroid, muscles, and central nervous system. METHODS: The current cross-sectional study included 56 patients with nephropathic cystinosis to evaluate the clinical outcome in nephropathic cystinosis patients cohort with regarding kidney function and the need for kidney replacement therapy. Clinical and laboratory data were collected. RESULTS: Among the 56 patients in our study, 32 (57.1%) were male. Furthermore, 52 (92%) of these patients were offspring of consanguineous marriage. Patients' mean age was 116.96 ± 54.1 months, and the mean onset of nephropathic cystinosis suggestive symptoms was 7.63 ± 3.2 months. In addition, the mean age of confirmed diagnosis was 45.38 ± 35.3 months, and the mean age of end-stage kidney disease (ESKD) was 104 ± 25.7 months. Eighteen patients (32.1%)underwent hemodialysis, whereas 12 patients (21.4%) underwent kidney transplantation. When comparing siblings within the same family, we observed a significant difference in the age at diagnosis. The median age for the first sibling was 60 months, while it was 24 months for the second sibling (p-value = 0.031). Additionally, there were significant differences in weight, chronic kidney disease (CKD) stage, and outcome. CONCLUSION: Improvement in the awareness and the accessibility to diagnosis over years, early sibling screening, and kidney transplantation have a significant impact on the survival of both patients and kidney in children with nephropathic cystinosis.