Inadequate iron availability as a possible cause of low serum carnitine concentrations in patients with phenylketonuria.
A previous observation of decreased serum carnitine concentrations in phenylketonuria (PKU) was investigated in 169 patients either on a strict diet (n = 107; median: 8.1 years) or off diet (n = 62; median: 15.0 years). Fifty-seven metabolically healthy children (median: 8.5 years) served as controls. PKU patients on a strict diet and older than 2 years had significantly lower serum carnitine concentrations (19.4 +/- 5.4 mumol/l) than those off diet (29.6 +/- 6.7 mumol/l). PKU patients on diet also had significantly lower concentrations of haemoglobin and serum ferritin than those off diet. A linear correlation existed between total serum carnitine and ferritin concentrations up to 40 micrograms/l (r = 0.52; P less than 0.01). As iron is an essential cofactor of carnitine synthesis we conclude that reduced endogenous carnitine synthesis due to an inadequate availability of iron may be a major cause of low serum carnitine concentrations. The low carnitine content of the strict and highly protein-reduced diet additionally contributes to a decrease in the serum carnitine concentration. Our results show that a further optimization of the PKU diet increasing either iron availability or carnitine intake should be considered.
Böhles
H
H
University Children's Hospital, Frankfurt/Main, Federal Republic of Germany.
Ullrich
K
K
Endres
W
W
Behbehani
A W
AW
Wendel
U
U
D000293:Adolescent; D000328:Adult; D002331:Carnitine / Q000096:biosynthesis / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005293:Ferritins / Q000032:analysis; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007223:Infant; D007501:Iron / Q000378:metabolism*; D010661:Phenylketonurias / Q000097:blood* / Q000178:diet therapy / Q000378:metabolism
D006454:Hemoglobins; D005293:Ferritins; D007501:Iron; D002331:Carnitine