Congenital megaconial myopathy due to a novel defect in the choline kinase Beta gene.
OBJECTIVE
To describe the first American patient with a congenital muscle dystrophy characterized by the presence in muscle of gigantic mitochondria displaced to the periphery of the fibers and to stress the potential origin and effects of the mitochondrial changes.


METHODS
Case report and documentation of a novel mutation in the gene encoding choline kinase beta (CHKB).


METHODS
Collaboration between 2 tertiary care academic institutions.


METHODS
A 2-year-old African American boy with weakness and psychomotor delay.


METHODS
Detailed clinical and laboratory studies, including muscle biopsy, biochemical analysis of the mitochondrial respiratory chain, and sequencing of the CHKB gene.


METHODS
Definition of unique mitochondrial changes in muscle.


RESULTS
This patient had the same clinical and laboratory features reported in the first cohort of patients, but he harbored a novel CHKB mutation and had isolated cytochrome c oxidase deficiency in muscle.


CONCLUSIONS
Besides confirming the phenotype of CHKB mutations, we propose that this disorder affects the mitochondria-associated membrane and the impaired phospholipid metabolism in the mitochondria-associated membrane causes both the abnormal size and displacement of muscle mitochondria.
Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA.
Purificacion
P
Gutiérrez Ríos
Arun A
AA
Kalra
Jon D
JD
Wilson
Kurenai
K
Tanji
Hasan O
HO
Akman
Estela
E
Area Gómez
Eric A
EA
Schon
Salvatore
S
DiMauro
D002675:Child, Preschool; D002797:Choline Kinase / Q000235:genetics*; D004252:DNA Mutational Analysis; D004579:Electron Transport / Q000235:genetics; D006801:Humans; D008297:Male; D017240:Mitochondrial Myopathies / Q000151:congenital / Q000235:genetics* / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology / Q000648:ultrastructure; D009154:Mutation / Q000235:genetics*
C542592:CHKB protein, human; D002797:Choline Kinase