Heteroplasmic mutation in the anticodon-stem of mitochondrial tRNA(Val) causing MNGIE-like gastrointestinal dysmotility and cachexia.
While mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is typically associated with mutations in the nuclear gene encoding for thymidine phosphorylase (ECGF1, TYMP), a similar clinical phenotype was described in patients carrying mutations in the nuclear-encoded polymerase gamma (POLG1) as well as a few mitochondrial tRNA genes. Here we report a novel mutation in the mitochondrial tRNA(Val) (MTTV) gene in a girl presenting with clinical symptoms of MNGIE-like gastrointestinal dysmotility and cachexia. Clinical, histological, biochemical and single cell investigations were performed. The heteroplasmic m.1630A>G mutation was detected in the mitochondrial tRNA(Val) (MTTV) gene in the patient's muscle, blood leukocytes and myoblasts, as well as in blood DNA of the unaffected mother. We provide clinical, biochemical, histological, and molecular genetic evidence on the single cell level for the pathogenicity of this mutation. Our finding adds to the genetic heterogeneity of MNGIE-like gastrointestinal symptoms and highlights the importance of a thorough genetic workup in case of suspected mitochondrial disease.
Horváth
Rita
R
Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Ziemssenstr. 1a, Munich 80336, Germany. Rita.Horvath@ncl.ac.uk
Bender
Andreas
A
Abicht
Angela
A
Holinski-Feder
Elke
E
Czermin
Birgit
B
Trips
Tobias
T
Schneiderat
Peter
P
Lochmüller
Hanns
H
Klopstock
Thomas
T
D000293:Adolescent; D017668:Age of Onset; D000926:Anticodon / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D002100:Cachexia / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D004252:DNA Mutational Analysis; D005260:Female; D005767:Gastrointestinal Diseases / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D005769:Gastrointestinal Motility / Q000235:genetics; D005808:Genes, Recessive / Q000235:genetics; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008928:Mitochondria / Q000235:genetics; D028361:Mitochondrial Diseases / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D009154:Mutation / Q000235:genetics*; D012313:RNA / Q000235:genetics*; D000077278:RNA, Mitochondrial; D012366:RNA, Transfer, Val / Q000235:genetics*; D014633:Valine / Q000235:genetics
D000926:Anticodon; D005819:Genetic Markers; D000077278:RNA, Mitochondrial; D012366:RNA, Transfer, Val; D012313:RNA; D014633:Valine