Recessive POLG mutations presenting with sensory and ataxic neuropathy in compound heterozygote patients with progressive external ophthalmoplegia.
Autosomal recessive progressive external ophthalmoplegia is a mitochondrial disease characterized by accumulation of multiple large-scale deletions of mitochondrial DNA. We previously reported missense mutations in POLG, the gene encoding the mitochondrial DNA polymerase gamma in two nuclear families compatible with autosomal recessive progressive external ophthalmoplegia. Here, we report a novel POLG missense mutation (R627W) in a sporadic patient and we provide genetic support that all these POLG mutations are actually causal and recessive. The novel patient presented with sensory ataxic neuropathy and has the clinical triad of sensory ataxic neuropathy, dysarthria and ophthalmoparesis (SANDO). This is the first finding of a genetic cause of Sensory Ataxic Neuropathy, Dysarthria and Ophthalmoparesis and it implies that this disorder may actually be a variant of autosomal recessive progressive external ophthalmoplegia. Sensory neuropathy is the initial feature in Belgian compound heterozygote autosomal recessive progressive external ophthalmoplegia patients, all carrying the POLG A467T mutation, which occurs at a frequency of 0.6% in the Belgian population.
Van Goethem
G
G
Neuromuscular Reference Center, University Hospital of Antwerp (UZA), Antwerpen, Belgium. vgoethge@uia.ua.ac.be
Martin
J J
JJ
Dermaut
B
B
Löfgren
A
A
Wibail
A
A
Ververken
D
D
Tack
P
P
Dehaene
I
I
Van Zandijcke
M
M
Moonen
M
M
Ceuterick
C
C
De Jonghe
P
P
Van Broeckhoven
C
C
D000293:Adolescent; D000328:Adult; D000368:Aged; D001120:Arginine / Q000235:genetics; D001259:Ataxia / Q000209:etiology / Q000235:genetics*; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase / Q000235:genetics* / Q000648:ultrastructure; D003576:Electron Transport Complex IV / Q000378:metabolism; D005260:Female; D005808:Genes, Recessive; D006579:Heterozygote; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure; D020125:Mutation, Missense; D017246:Ophthalmoplegia, Chronic Progressive External / Q000150:complications / Q000235:genetics*; D010375:Pedigree; D013385:Succinate Dehydrogenase / Q000378:metabolism; D014364:Tryptophan / Q000235:genetics
D014364:Tryptophan; D001120:Arginine; D013385:Succinate Dehydrogenase; D003576:Electron Transport Complex IV; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase; C413027:POLG protein, human