RESUMEN
UNLABELLED: We describe a 6-year-old girl admitted with acute muscular weakness and pain which made her unable to walk. Her parents reported a 4-year history of similar episodes which occurred once or twice a year and always resolved spontaneously. Laboratory investigations showed elevated serum creatine kinase which peaked at day 2 of the attack with 18,600 U/l. Carnitine palmitoyltransferase-II deficiency was suspected based on the determination of serum acylcarnitines by tandem mass spectrometry which showed a characteristic elevation of long-chain C16 and C18:1 acylcarnitines. The diagnosis was confirmed by impaired in-vitro palmitate oxidation in blood and the detection of a homozygous substitution S113L in the carnitine palmitoyltransferase-II gene. CONCLUSION: Carnitine palmitoyltransferase-II deficiency should be included in the differential diagnosis of isolated muscular weakness even when manifesting in early childhood.
Asunto(s)
Carnitina O-Palmitoiltransferasa/deficiencia , Trastornos Miotónicos/diagnóstico , Trastornos Miotónicos/enzimología , Edad de Inicio , Carnitina O-Palmitoiltransferasa/genética , Estudios de Casos y Controles , Niño , Diagnóstico Diferencial , Femenino , Humanos , Espectrometría de Masas , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de RestricciónRESUMEN
The uncoupling protein 1 (UCP1), a mitochondrial transmembrane protein, is responsible for adaptive thermogenesis in brown adipose tissue (BAT). Two UCP1 homologues, UCP2 and UCP3, were recently discovered, but it is controversial whether they also play a role in energy homeostasis. Djungarian hamster UCPs were found to exhibit high similarity with homologues known in other species. UCP1 mRNA was restricted to BAT, UCP2 mRNA was expressed in multiple tissues, and UCP3 mRNA was detected mainly in BAT and skeletal muscles. We examined the cold-induced regulation of hamster UCP mRNA levels and tested their correlation with serum free fatty acid (FFA) concentrations. In BAT UCP1, UCP2, and UCP3 expression was upregulated in the cold, but the increase and time course of increase differed. In skeletal muscle, UCP2 and UCP3 mRNA levels were not altered. Cold-induced changes of serum FFA levels correlated with the stimulation of UCP1 mRNA in BAT but not with UCP2 and UCP3.