Paroxysmal kinesigenic dyskinesia and infantile convulsions: clinical and linkage studies.
OBJECTIVE
To clinically characterize affected individuals in families with paroxysmal kinesigenic dyskinesia (PKD), examine the association with infantile convulsions, and confirm linkage to a pericentromeric chromosome 16 locus.


BACKGROUND
PKD is characterized by frequent, recurrent attacks of involuntary movement or posturing in response to sudden movement, stress, or excitement. Recently, an autosomal dominant PKD locus on chromosome 16 was identified.


METHODS
The authors studied 11 previously unreported families of diverse ethnic background with PKD with or without infantile convulsions and performed linkage analysis with markers spanning the chromosome 16 locus. Detailed clinical questionnaires and interviews were conducted with affected and unaffected family members.


RESULTS
Clinical characterization and sampling of 95 individuals in 11 families revealed 44 individuals with paroxysmal dyskinesia, infantile convulsions, or both. Infantile convulsions were surprisingly common, occurring in 9 of 11 families. In only two individuals did generalized seizures occur in later childhood or adulthood. The authors defined a 26-cM region using linkage data in 11 families (maximum lod score 6.63 at theta = 0). Affected individuals in one family showed no evidence for a shared haplotype in this region, implying locus heterogeneity.


CONCLUSIONS
Identification and characterization of the PKD/infantile convulsions gene will provide new insight into the pathophysiology of this disorder, which spans the phenotypic spectrum between epilepsy and movement disorder.
Swoboda
K J
KJ
Department of Neurology, Human Genetics, Howard Hughes Medical Institute, Salt Lake City, UT, USA. Swoboda@howard.genetics.utah.edu
Soong
B
B
McKenna
C
C
Brunt
E R
ER
Litt
M
M
Bale
J F
JF
Ashizawa
T
T
Bennett
L B
LB
Bowcock
A M
AM
Roach
E S
ES
Gerson
D
D
Matsuura
T
T
Heydemann
P T
PT
Nespeca
M P
MP
Jankovic
J
J
Leppert
M
M
Ptácek
L J
LJ
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002819:Chorea / Q000175:diagnosis / Q000235:genetics*; D002874:Chromosome Mapping; D002885:Chromosomes, Human, Pair 16; D005260:Female; D006580:Genetic Carrier Screening; D008040:Genetic Linkage / Q000235:genetics*; D005819:Genetic Markers / Q000235:genetics; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010375:Pedigree; D010641:Phenotype; D013036:Spasms, Infantile / Q000175:diagnosis / Q000235:genetics*
D005819:Genetic Markers