Large-single scale mitochondrial DNA deletions in different tissues in Kearns-Sayre syndrome / 中华实用儿科临床杂志

ABSTRACT

Objective To investigate the clinical significance of different samples (the peripheral blood,urine and skeletal muscle) that could be detected the large-scale single deletions directly by using next-generation sequencing in the diagnosis of Kearns-Sayre syndrome (KSS) by concluding the clinical and genetic features of KSS,in order to explore a non-invasive method for diagnosis.Methods The clinical data,skeletal muscle's pathology and enzymology and genetic results of individuals with KSS,who were hospitalized from October 2016 to October 2017 in Department of Neurology,Beijing Children's Hospital,Capital Medical University,were collected.The gene tests were performed by using next generation sequencing technology and long-PCR technology of mitochondrial DNA(mtDNA) and the whole exon in the peripheral blood,urine and skeletal muscle.Results Four patients were all consistent with the diagnosis criteria of KSS,among whom the age of onset was 8.2 years old on average,and the initial symptoms were statue,ptosis,headache and vomiting,and visual impairment.The common symptoms of the 4 cases were ophthalmoplegia,exercise intolerance,development delay,loss of appetite,hypotonia,muscle weakness,with cerebrospinal fluid protein concentration over 1 000 mg/L,the cerebral magnetic resonance imaging showed that abnormal signals in the brainstem,in addition,white matter,thalamus,basal ganglia,cerebrum and cerebellum atrophy could be found.Moreover,3 cases had cardiac conduction block.Two cases had maternal family history.Molecular analysis of the 4 cases revealed the large-scale single deletions of mtDNA from the peripheral blood,the urine,the skeletal muscle through the nextgeneration sequencing,which were m.6460-15590(9 131 bp del),m.8482-13446(4 964 bp del),m.6831-14981 (8 151 bp del),m.7983-15495 (7 513 bp del),respectively.Among 3 cases who did pedigree analysis,only the mother of case 4 was detected with the same variation of the proband.Conclusions KSS is a rare mitochondrial disease,which could be detected with the single large scale mtDNA deletions in the peripheral blood,urine and skeletal muscle.With the development of the methodology,the diagnosis of KSS maybe no longer than depends on the muscle biopsy with the next-generation sequencing.And the possibility to get the positive results in the peripheral blood and urine by the non-invasive method could improve the molecular diagnosis of KSS.