Pathology Department, The SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil.
Neurophysiology Department, The SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil.
Neuromuscul Disord. 2021 Jun;31(6):551-557. doi: 10.1016/j.nmd.2021.02.017. Epub 2021 Feb 21.
Reversible infantile respiratory chain deficiency is a severe neonatal mitochondrial myopathy that resolves spontaneously. It is caused by the homoplasmic m.14674T>C mtDNA mutation and additional nuclear variants in genes interacting with mt-tRNAGlu have been detected in some patients. We present detailed clinical, imaging, and muscle biopsy findings in a boy and a girl with neonatal hypotonia, feeding difficulties, lactic acidosis, and ragged red fibers. Both patients show fat replacement on muscle imaging, which was mild in the boy, but severe in the girl, affecting mostly the posterior leg muscles. In addition to the homoplasmic m.14674T>C, both patients carried heterozygous variants in QRSL1 (c. 686T>G; p.Val299Gly) and EARS2 (c.358C>T; p.Arg120Trp), respectively. It is very important to recognize the clinical and morphological signs of reversible infantile respiratory chain deficiency as patients should receive intensive supportive care in the first 6 months of life. Understanding the mechanism of the spontaneous recovery may lead to novel therapeutic perspectives in other mitochondrial diseases.
可逆性婴儿呼吸链缺陷是一种严重的新生儿线粒体肌病，可自发缓解。它是由同质型 m.14674T>C mtDNA 突变引起的，在一些患者中还检测到与 mt-tRNAGlu 相互作用的核基因中的额外变体。我们介绍了一男一女两名新生儿肌张力低下、喂养困难、乳酸性酸中毒和红纤维杂乱患者的详细临床、影像学和肌肉活检结果。两名患者的肌肉影像学均显示脂肪替代，男孩轻度，女孩严重，主要影响后腿肌肉。除同质型 m.14674T>C 外，两名患者分别携带 QRSL1（c.686T>G；p.Val299Gly）和 EARS2（c.358C>T；p.Arg120Trp）的杂合变体。非常重要的是要认识到可逆性婴儿呼吸链缺陷的临床和形态学特征，因为患者在生命的前 6 个月应接受强化支持治疗。了解自发恢复的机制可能会为其他线粒体疾病带来新的治疗前景。
