Table 3.

Clinical characteristics according to mutation group

General FeaturesMissense MutationsDeletion/Duplication/Splice/Missense MutationsaP Value
No. of patients3461
Boys/girls, n18/1634/270.79
Age at diagnosis, median (IQR), yr2 (1–8)2 (1–3)0.11
Age at the last follow-up visit, mean±SD, yr13±710±60.10
Duration of follow-up, mean±SD, yr8±77±60.51
Cysteamine dose, mean±SD, mg⋅kg–1⋅d–151.0±12.452.1±11.80.85
Age at onset of ESRD, mean±SD, yr12±610±30.79
eGFR at last follow-up visit,b mean±SD, yr90±5068±410.09
Leukocyte cystine level,c median (IQR)1.6 (1.6–3.6)1.5 (0.6–4.1)0.82
Systemic findings, n0.51
 Hypothyroidism719
 Rickets1321
 Gastrointestinal involvement24
RRT at the last follow-up visit (patient no.), n0.95
 Peritoneal dialysis55
 Hemodialysis17
 Transplantation711
  • IQR, interquartile range.

  • a Three missense mutations (c.681G>A [p.Glu227Glu], c.664C>T [p.Gln222*], and c.G14A [p.Trp5*]).

  • b After exclusion of patients undergoing RRT.

  • c Nanomole half-cystine per milligram protein.