Infantile lipid storage myopathy with nocturnal hypoventilation shows abnormal low-affinity muscle carnitine uptake in vitro.
An infant with respiratory insufficiency, cardiomyopathy, lipid storage myopathy and low muscle carnitine was diagnosed as having 'Ondine's curse' because of recurrent nocturnal hypoventilation. Carnitine uptake was studied in 20-day-old cultured muscle, where two distinct saturable transport components are recognized: the high- and low-affinity-uptake. Experimental evidence suggests that low-affinity-uptake is muscle-specific, operating at physiological carnitine concentration. In the patient's cultured myotubes, the low-affinity-uptake K(m) was 260% of controls (P < 0.01), whereas kinetic parameters of high-affinity uptake were normal. The high K(m) indicates an immature or altered carnitine muscle carrier, which may decrease the physiologic carnitine uptake.
Vergani
L
L
Dipartimento di Scienze Neurologiche e Psichiatriche, Università di Padova, Italy.
Angelini
C
C
D002331:Carnitine / Q000493:pharmacokinetics*; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D007040:Hypoventilation / Q000209:etiology*; D007223:Infant; D008052:Lipid Metabolism, Inborn Errors / Q000150:complications / Q000473:pathology*; D009132:Muscles / Q000166:cytology / Q000378:metabolism*; D009135:Muscular Diseases / Q000150:complications / Q000473:pathology*; D012132:Respiratory Muscles / Q000473:pathology
D002331:Carnitine