A longitudinal study of Taiwanese sialidosis type 1: an insight into the concept of cherry-red spot myoclonus syndrome.
OBJECTIVE
Sialidosis type 1 (ST-1) is a neurodegenerative disorder with limited long-term follow-up report. This study is to document the chronological profile of ST-1.


METHODS
We perform serial analysis of 17 Taiwanese patients with ST-1 focusing on evolution of clinical features, electrophysiological findings, genetic studies, and neuroimage examinations.


RESULTS
All patients had a mutation at 554A-->G in exon 3 of the NEU1 gene causing Ser182Gly substitution. Fifteen patients were homozygous. Two patients were heterozygous with novel mutations, 956C-->T causing Ala319Val in one and 163C-->T causing Gln55stop codon in the other. The neuraminidase activity was markedly decreased in all 11 available patients. Only three patients (17.6%) manifested the macular cherry-red spot. The majority of patients (82.3%) developed full-blown manifestation of myoclonus, ataxia, and seizures within 5 years. Abnormal somatosensory evoked potentials with giant cortical waves were found in all patients. Prolonged P100 peak latency of the visual evoked potentials (VEPs) were found in 16 patients (94.1%) in the early stage even without visual symptoms.


CONCLUSIONS
ST-1 in Taiwanese population illustrates distinct characteristics of phenotype with infrequent cherry-red spot. We suggest to screen the NEU1 mutations in patients presenting action myoclonus with abnormal VEPs, even without macular cherry-red spots.
Lai
S-C
SC
Neuroscience Research Center, Chang Gung University College of Medicine, Taoyuan, Taiwan.
Chen
R-S
RS
Wu Chou
Y-H
YH
Chang
H-C
HC
Kao
L-Y
LY
Huang
Y-Z
YZ
Weng
Y-H
YH
Chen
J-K
JK
Hwu
W-L
WL
Lu
C-S
CS
D000293:Adolescent; D000328:Adult; D001259:Ataxia / Q000201:enzymology / Q000235:genetics / Q000503:physiopathology; D002648:Child; D018450:Disease Progression; D005073:Evoked Potentials, Somatosensory; D005074:Evoked Potentials, Visual; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009081:Mucolipidoses / Q000201:enzymology / Q000235:genetics* / Q000503:physiopathology*; D020125:Mutation, Missense; D009207:Myoclonus / Q000201:enzymology / Q000235:genetics / Q000503:physiopathology; D009439:Neuraminidase / Q000235:genetics* / Q000378:metabolism; D019636:Neurodegenerative Diseases / Q000201:enzymology / Q000235:genetics* / Q000503:physiopathology*; D012640:Seizures / Q000201:enzymology / Q000235:genetics / Q000503:physiopathology; D013624:Taiwan; D055815:Young Adult
C486385:NEU1 protein, human; D009439:Neuraminidase