Table 4.

Clinical characteristics of the patients with the most common homozygous mutations and the other homozygous mutations

General FeaturesMost Common MutationsaOthersP Value
Patients, n6225
Boys/girls, n32/3014/110.71
Age at diagnosis, median (IQR), yr1 (1–4)3 (2–9)0.04
Age at last follow-up visit, mean±SD, yr9±514±70.01
Duration of follow-up, mean±SD, yr7±57±70.85
Cysteamine dose, mean±SD, mg⋅kg–1⋅d–151.0±11.354.7±12.20.49
Age of ESRD, mean±SD, yr10±312±70.81
eGFRa at last follow-up visitb73±4873±390.79
Leukocyte cystine level,c median (IQR)2.3 (0.5–4.2)1.5 (0.6–4.0)0.95
Systemic findings, n0.51
 Hypothyroidism178
 Rickets2011
 Gastroesophageal reflux33
RRT at the last follow-up visit (patient no.), n0.95
 Peritoneal dialysis72
 Hemodialysis53
 Transplantation134
  • IQR, interquartile range.

  • a The most common homozygous mutations were c.681G>A (p.Glu227Glu), c.1015G>A (p.Gly339Arg), and c.18_21 del (p.Thr7Phefs*7). Other homozygous mutations include c140+1G>T, c.451A>G (p.Arg151Gly), c. 960del (p.Tyr321Thrfs*8), c.834_842del (p. Val279_Tyr281del), c.518A>G (p.Tyr173Cys), c.853–1G>A, c.62–1083_c.551del10217, c.829 dup (p.Thr277Asnfs*19), c.470 G>A (p.Gly157Asp), c.141–22A>G, c.291_294delTACT (p.Thr98Phefs*19), c.664C>T (p.Gln222*), and c.G14A (p.Trp5*).

  • b After exclusion of patients undergoing RRT.

  • c Nanomole half-cystine per milligram protein.