Ramsay Hunt syndrome: clinical characterization of progressive myoclonus ataxia caused by GOSR2 mutation.
BACKGROUND
Ramsay Hunt syndrome (progressive myoclonus ataxia) is a descriptive diagnosis characterized by myoclonus, ataxia, and infrequent seizures. Often the etiology cannot be determined. Recently, a mutation in the GOSR2 gene (c.430G>T, p.Gly144Trp) was reported in 6 patients with childhood-onset progressive ataxia and myoclonus.


METHODS
We evaluated 5 patients with cortical myoclonus, ataxia, and areflexia.


RESULTS
All 5 patients had the same homozygous mutation in GOSR2. Here we present their clinical and neurophysiological data. Our patients (aged 7-26 years) all originated from the northern Netherlands and showed a remarkably homogeneous phenotype. Myoclonus and ataxia were relentlessly progressive over the years. Electromyography revealed signs of sensory neuronopathy or anterior horn cell involvement, or both, in all patients with absent reflexes.


CONCLUSIONS
Based on the presented phenotype, we would advise movement disorder specialists to consider mutation analysis of GOSR2 in patients with Ramsay Hunt syndrome, especially when they also have areflexia.
Department of Neurology, University of Groningen, University Medical Center Groningen, The Netherlands.
Martje E
ME
van Egmond
Corien C
CC
Verschuuren-Bemelmans
Esther A
EA
Nibbeling
Jan Willem J
JW
Elting
Deborah A
DA
Sival
Oebele F
OF
Brouwer
Jeroen J
JJ
de Vries
Hubertus P
HP
Kremer
Richard J
RJ
Sinke
Marina A
MA
Tijssen
Tom J
TJ
de Koning
D000328:Adult; D002648:Child; D004252:DNA Mutational Analysis; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009154:Mutation; D002527:Myoclonic Cerebellar Dyssynergia / Q000235:genetics* / Q000503:physiopathology; D009213:Myography; D010641:Phenotype; D050766:Qb-SNARE Proteins / Q000235:genetics*; D055815:Young Adult
C491344:GOSR2 protein, human; D050766:Qb-SNARE Proteins
GOSR2 mutation; Ramsay Hunt; ataxia; myoclonus; progressive myoclonus ataxia