MELAS syndrome : 
 Point mutation at nt 3243 (A3243G) in tRNALeu(UUR) gene of mtDNA

J Korean Neurol Assoc > Volume 16(4); 1998 > Article

Journal of the Korean Neurological Association 1998;16(4): 585-589.

사립체 DNA 뉴클레오타이드 3243 A→G 돌연변이 [MTTL1*MELAS3243G]에 의한 MELAS 증후군

박기형, 김승현ㆍ이영주ㆍ김희태ㆍ김주한ㆍ김명호ㆍ박성섭*

한양대학교 신경과학교실, 서울대학교 임상병리학교실*

MELAS syndrome : Point mutation at nt 3243 (A3243G) in tRNALeu(UUR) gene of mtDNA

Kee-Hyung Park M.D., Seung-Hyun Kim M.D., Young-Joo Lee M.D., Hee-Tae Kim M.D., Ju-Han Kim M.D., Myung-Ho Kim M.D., Sung-Sup Park M.D.*

Department of Neurology, College of Medicine, Hanyang University, Department of Clinical Pathology, Seoul National University College of Medicine*

Abstract

MELAS (Mitochondrial Encephalomyopathy with Lactic acidosis, and Stroke-like episodes) is a major maternally inherited mitochondrial(mt) encephalopathy, a disease in which 80% of cases are associated with mtDNA point mutation (nt A3243G in tRNALeu(UUR)). We report a case of MELAS syndrome confirmed by typical clinical presentation, muscle biopsy, and molecular genetic diagnosis. A patient was 14-year-old male presenting repeated episode of right hemiparesis and visual field defect. He is exhibited a short stature with dull appearance. On neurologic examination, right homonymous hemianopsia, right hemiparesis, and right side hypesthesia are noted. Brain MRI showed multiple signal changes lesion in left thalamus, right occipital and both temporal regions. Level of lactic acid in serum and CSF was highly increased. Ragged red fibers were shown in the modified Gomori-Trichrome staining, and electromicroscopic finding showed on accumulation of variable sized mitochondrias and glycogen particles in some areas of subsarcolemmal and interfibrillar areas. The mitochondrial tRNALeu(UUR) 3243 A to G mutation was identified by PCR/restriction endonuclease and sequencing. The ratio of mutation in leukocytes of proband and proband's mother was 50% and 10%, respectively. We report a case of MELAS syndromes showing mitochondrial tRNALeu(UUR) 3243 A to G mutation Key word : MELAS, Mitochondrial DNA, Point mutation