Mochel Fanny, Knight Melanie A, Tong Wing-Hang, Hernandez Dena, Ayyad Karen, Taivassalo Tanja, Andersen Peter M, Singleton Andrew, Rouault Tracey A, Fischbeck Kenneth H, Haller Ronald G
Developmental and Metabolic Neurology Branch, NINDS, NIH, Bethesda, MD 20892, USA.
Am J Hum Genet. 2008 Mar;82(3):652-60. doi: 10.1016/j.ajhg.2007.12.012. Epub 2008 Feb 14.
A myopathy with severe exercise intolerance and myoglobinuria has been described in patients from northern Sweden, with associated deficiencies of succinate dehydrogenase and aconitase in skeletal muscle. We identified the gene for the iron-sulfur cluster scaffold protein ISCU as a candidate within a region of shared homozygosity among patients with this disease. We found a single mutation in ISCU that likely strengthens a weak splice acceptor site, with consequent exon retention. A marked reduction of ISCU mRNA and mitochondrial ISCU protein in patient muscle was associated with a decrease in the iron regulatory protein IRP1 and intracellular iron overload in skeletal muscle, consistent with a muscle-specific alteration of iron homeostasis in this disease. ISCU interacts with the Friedreich ataxia gene product frataxin in iron-sulfur cluster biosynthesis. Our results therefore extend the range of known human diseases that are caused by defects in iron-sulfur cluster biogenesis.
瑞典北部的患者中曾有过关于一种伴有严重运动不耐受和肌红蛋白尿的肌病的描述，这些患者的骨骼肌中琥珀酸脱氢酶和乌头酸酶存在相关缺陷。我们将铁硫簇支架蛋白ISCU的基因确定为患有这种疾病的患者中共享纯合区域内的一个候选基因。我们在ISCU中发现了一个单一突变，该突变可能强化了一个弱剪接受体位点，从而导致外显子保留。患者肌肉中ISCU mRNA和线粒体ISCU蛋白的显著减少与铁调节蛋白IRP1的减少以及骨骼肌中的细胞内铁过载有关，这与该疾病中铁稳态的肌肉特异性改变一致。在铁硫簇生物合成过程中，ISCU与弗里德赖希共济失调基因产物frataxin相互作用。因此，我们的研究结果扩展了由铁硫簇生物合成缺陷导致的已知人类疾病的范围。
