J Korean Neurol Assoc.  1998 Aug;16(4):585-589.

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

• Park KH
• Kim SH
• Lee YJ
• Kim HT
• Kim JH
• Kim MH
• Park SS

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.

Keyword

MELAS; Mitochondrial DNA; Point mutation

MeSH Terms

Acidosis, Lactic
Adolescent
Biopsy
Brain
Diagnosis
DNA, Mitochondrial*
Glycogen
Hemianopsia
Humans
Hypesthesia
Lactic Acid
Leukocytes
Magnetic Resonance Imaging
Male
MELAS Syndrome*
Mitochondria
Molecular Biology
Mothers
Neurologic Examination
Paresis
Point Mutation*
Thalamus
Visual Fields
DNA, Mitochondrial
Glycogen
Lactic Acid