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Systemic primary carnitine deficiency, (SPCD) also known as carnitine uptake defect, carnitine transporter deficiency (CTD) or systemic carnitine deficiency is an inborn error of fatty acid transport caused by a defect in the transporter responsible for moving carnitine across the plasma membrane. Carnitine is an important amino acid for fatty acid metabolism.〔(Activation and Transportation of Fatty Acids for Metabolism via Carnitine Shuttle )〕 When carnitine cannot be transported into tissues, fatty acid oxidation is impaired, leading to a variety of symptoms such as chronic muscle weakness, cardiomyopathy, hypoglycemia and liver dysfunction. The specific transporter involved with SPCD is OCTN2, coded for by the ''SLC22A5'' gene located on chromosome 5. SPCD is inherited in an autosomal recessive manner, with mutated alleles coming from both parents. Acute episodes due to SPCD are often preceded by metabolic stress such as extended fasting, infections or vomiting. Cardiomyopathy can develop in the absence of an acute episode, and can result in death. SPCD leads to increased carnitine excretion in the urine and low levels in plasma. In most locations with expanded newborn screening, SPCD can be identified and treated shortly after birth. Treatment with high doses of carnitine supplementation is effective, but needs to be rigorously maintained for life. SPCD is more common in the Faroe Islands than in other countries, at least one out of every 1000 inhabitants of the Faroes has the illness,〔(Hmr.fo - Faroe Islands Ministry of Health - Information om CTD (Carnitin Transporter Defekt) )〕 while the numbers for other countries are one in every 100,000. Around 100 persons in the islands have been diagnosed, around one third of the whole population of 48,000 people have been screened for SPCD. Several young Faroese people and children have died a sudden death with cardiac arrest because of SPCD. Scientists believe that around 10% of the Faroese polutation are carriers of the gene for SPCD.〔(Dr.dk - Livsfarlig sygdom angriber færinge - By Tine Maria Borresø, 17 May 2010 )〕 These people are not ill, but may have a lower amount of carnitine in their blood than non-carriers. ==Signs and symptoms== The presentation of patient with SPCD can be incredibly varied, from asymptomatic to lethal cardiac manifestations.〔(【引用サイトリンク】url=http://omim.org/entry/212140 )〕 Early cases were reported with liver dysfunction, muscular findings (weakness and underdevelopment), hypoketotic hypoglycemia, cardiomegaly, cardiomyopathy and marked carnitine deficiency in plasma and tissues, combined with increased excretion in urine.〔 Patients who present clinically with SPCD fall into two categories, a metabolic presentation with hypoglycemia and a cardiac presentation characterized by cardiomyopathy. Muscle weakness can be found with either presentation. In countries with expanded newborn screening, SPCD can be identified shortly after birth. Affected infants show low levels of free carnitine and all other acylcarnitine species by tandem mass spectrometry.〔 Not all infants with low free carnitine are affected with SPCD. Some may have carnitine deficiency secondary to another metabolic condition or due to maternal carnitine deficiency. Proper follow-up of newborn screening results for low free carnitine includes studies of the mother to determine whether her carnitine deficiency is due to SPCD or secondary to a metabolic disease or diet. Maternal cases of SPCD have been identified at a higher than expected rate, often in women who are asymptomatic.〔 Some mothers have also been identified through newborn screening with cardiomyopathy that had not been previously diagnosed. The identification and treatment of these asymptomatic individuals is still developing, as it is not clear whether they require the same levels of intervention as patients identified with SPCD early in life based on clinical presentation.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Systemic primary carnitine deficiency」の詳細全文を読む スポンサード リンク
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