TY - CHAP
T1 - Carnitine profile and effect of suppletion in children with renal fanconi syndrome due to cystinosis
AU - Besouw, M.
AU - Cornelissen, E.
AU - Cassiman, D.
AU - Kluijtmans, L.
AU - van den Heuvel, L.
AU - Levtchenko, E.
N1 - Publisher Copyright: © SSIEM and Springer-Verlag Berlin Heidelberg 2014.
PY - 2014
Y1 - 2014
N2 - Background: Cystinosis is an autosomal recessive disorder marked by intralysosomal cystine accumulation. Patients present with generalized proximal tubular dysfunction called renal Fanconi syndrome. Urinary carnitine loss results in plasma and muscle carnitine deficiency, but no clinical signs of carnitine deficiency have been described. Also, the optimal dose of carnitine supplementation is undefined. This study aimed to determine whether currently recommended carnitine doses result in adequate correction of plasma carnitine. Methods: Five cystinosis patients with renal Fanconi syndrome, aged 2–18 years, were included. l-carnitine was prescribed 50 mg/kg/day since diagnosis: median 36 (range 18–207) months. Total and free plasma and urine carnitine and carnitine profiles were measured at study onset, after stopping l-carnitine for 3 months and 3 months after reintroducing l-carnitine 50 mg/kg/day. Results: At study onset, plasma free carnitine was normal in all patients, total carnitine (1/5), acetylcarnitine (3/5), and several short- and medium-chain acylcarnitines ≤10 carbons (5/5) were increased indicating carnitine over-supplementation. Three months after cessation, carnitine profiles normalized and 3/5 patients showed plasma carnitine deficiency. Three months after reintroduction, plasma free carnitine normalized in all patients, however, carnitine profiles were disturbed in 4/5 patients. Urine free carnitine, acetylcarnitine, and acylcarnitines ≤10 carbons were increased in all patients independent of carnitine supplementation. Conclusion: Administration of recommended doses l-carnitine (50 mg/kg/day) resulted in over-supplementation. Although the drug is considered to be rather safe, long-term effects of over-supplementation remain unknown warranting cautious use of high doses. Plasma carnitine profile might be used as a monitor, to prevent overdosing.
AB - Background: Cystinosis is an autosomal recessive disorder marked by intralysosomal cystine accumulation. Patients present with generalized proximal tubular dysfunction called renal Fanconi syndrome. Urinary carnitine loss results in plasma and muscle carnitine deficiency, but no clinical signs of carnitine deficiency have been described. Also, the optimal dose of carnitine supplementation is undefined. This study aimed to determine whether currently recommended carnitine doses result in adequate correction of plasma carnitine. Methods: Five cystinosis patients with renal Fanconi syndrome, aged 2–18 years, were included. l-carnitine was prescribed 50 mg/kg/day since diagnosis: median 36 (range 18–207) months. Total and free plasma and urine carnitine and carnitine profiles were measured at study onset, after stopping l-carnitine for 3 months and 3 months after reintroducing l-carnitine 50 mg/kg/day. Results: At study onset, plasma free carnitine was normal in all patients, total carnitine (1/5), acetylcarnitine (3/5), and several short- and medium-chain acylcarnitines ≤10 carbons (5/5) were increased indicating carnitine over-supplementation. Three months after cessation, carnitine profiles normalized and 3/5 patients showed plasma carnitine deficiency. Three months after reintroduction, plasma free carnitine normalized in all patients, however, carnitine profiles were disturbed in 4/5 patients. Urine free carnitine, acetylcarnitine, and acylcarnitines ≤10 carbons were increased in all patients independent of carnitine supplementation. Conclusion: Administration of recommended doses l-carnitine (50 mg/kg/day) resulted in over-supplementation. Although the drug is considered to be rather safe, long-term effects of over-supplementation remain unknown warranting cautious use of high doses. Plasma carnitine profile might be used as a monitor, to prevent overdosing.
KW - Carnitine deficiency
KW - Carnitine level
KW - Carnitine supplementation
KW - Free carnitine
KW - Total carnitine
UR - http://www.scopus.com/inward/record.url?scp=84949934977&partnerID=8YFLogxK
U2 - https://doi.org/10.1007/8904_2014_312
DO - https://doi.org/10.1007/8904_2014_312
M3 - Chapter
T3 - JIMD Reports
SP - 25
EP - 30
BT - JIMD Reports
PB - Springer
ER -