Phenotypic features of myoclonus-dystonia in three kindreds.
BACKGROUND
Myoclonus-dystonia (M-D) is a movement disorder with involuntary jerks and dystonic contractions. Autosomal dominant alcohol-responsive M-D is associated with mutations in the epsilon-sarcoglycan gene (SGCE) (six families) and with a missense change in the D2 dopamine receptor (DRD2)gene (one family).


OBJECTIVE
To investigate the clinical phenotype associated with M-D including motor symptoms, psychiatric disorders, and neuropsychological deficits.


METHODS
Fifty individuals in three M-D families were evaluated and a standardized neurologic examination and DNA analysis were performed. Psychiatric profiles were established with the Diagnostic Interviews for Genetic Studies (DIGS) and the Yale-Brown Obsessive-Compulsive Scale (YBOCS). Cognition was evaluated with standardized neuropsychological tests.


RESULTS
Distinct truncating mutations in the SGCE gene were identified in each family. Additionally, a missense alteration in the DRD2 gene was previously found in one family. Motor expression was variable, with onset of myoclonus or dystonia or both affecting the upper body and progression to myoclonus and dystonia in most cases. Psychiatric profiles revealed depression, obsessive-compulsive disorder, substance abuse, anxiety/panic/phobic disorders, and psychosis in two families, and depression only in the third family. Averaged scores from cognitive testing showed impaired verbal learning and memory in one family, impaired memory in the second family, and no cognitive deficits in the third family.


CONCLUSIONS
Cognitive deficits may be associated with M-D. Psychiatric abnormalities correlate with the motor symptoms in affected individuals. Assessment of additional M-D families with known mutations is needed to determine whether these are characteristic phenotypic manifestations of M-D.
Doheny
D O
DO
Department of Neurology, Mount Sinai School of Medicine, Annenberg 14-51A, Box 1052, New York, NY 10029, USA. Dana.Doheny@mssm.edu
Brin
M F
MF
Morrison
C E
CE
Smith
C J
CJ
Walker
R H
RH
Abbasi
S
S
Müller
B
B
Garrels
J
J
Liu
L
L
De Carvalho Aguiar
P
P
Schilling
K
K
Kramer
P
P
De Leon
D
D
Raymond
D
D
Saunders-Pullman
R
R
Klein
C
C
Bressman
S B
SB
Schmand
B
B
Tijssen
M A J
MA
Ozelius
L J
LJ
Silverman
J M
JM
D000328:Adult; D000368:Aged; D002648:Child; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics; D002897:Chromosomes, Human, Pair 7 / Q000235:genetics; D003071:Cognition; D004421:Dystonia / Q000235:genetics* / Q000503:physiopathology / Q000523:psychology; D005260:Female; D008040:Genetic Linkage / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000235:genetics; D020125:Mutation, Missense / Q000235:genetics; D009207:Myoclonus / Q000235:genetics* / Q000503:physiopathology / Q000523:psychology; D010375:Pedigree; D010641:Phenotype; D017448:Receptors, Dopamine D2 / Q000235:genetics
D017448:Receptors, Dopamine D2