Cardiac ankyrin repeat protein gene (ANKRD1) mutations in hypertrophic cardiomyopathy.
OBJECTIVE
The purpose of this study was to explore a novel disease gene for hypertrophic cardiomyopathy (HCM) and to evaluate functional alterations caused by mutations.


BACKGROUND
Mutations in genes encoding myofilaments or Z-disc proteins of the cardiac sarcomere cause HCM, but the disease-causing mutations can be found in one-half of the patients, indicating that novel HCM-susceptibility genes await discovery. We studied a candidate gene, ankyrin repeat domain 1 (ANKRD1), encoding for the cardiac ankyrin repeat protein (CARP) that is a Z-disc component interacting with N2A domain of titin/connectin and N-terminal domain of myopalladin.


METHODS
We analyzed 384 HCM patients for mutations in ANKRD1 and in the N2A domain of titin/connectin gene (TTN). Interaction of CARP with titin/connectin or myopalladin was investigated using coimmunoprecipitation assay to demonstrate the functional alteration caused by ANKRD1 or TTN mutations. Functional abnormalities caused by the ANKRD1 mutations were also examined at the cellular level in neonatal rat cardiomyocytes.


RESULTS
Three ANKRD1 missense mutations, Pro52Ala, Thr123Met, and Ile280Val, were found in 3 patients. All mutations increased binding of CARP to both titin/connectin and myopalladin. In addition, TTN mutations, Arg8500His, and Arg8604Gln in the N2A domain were found in 2 patients, and these mutations increased binding of titin/connectin to CARP. Myc-tagged CARP showed that the mutations resulted in abnormal localization of CARP in cardiomyocytes.


CONCLUSIONS
CARP abnormalities may be involved in the pathogenesis of HCM.
Arimura
Takuro
T
Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan. akitis@mri.tmd.ac.jp
Bos
J Martijn
JM
Sato
Akinori
A
Kubo
Toru
T
Okamoto
Hiroshi
H
Nishi
Hirofumi
H
Harada
Haruhito
H
Koga
Yoshinori
Y
Moulik
Mousumi
M
Doi
Yoshinori L
YL
Towbin
Jeffrey A
JA
Ackerman
Michael J
MJ
Kimura
Akinori
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002312:Cardiomyopathy, Hypertrophic / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D009124:Muscle Proteins / Q000235:genetics*; D020125:Mutation, Missense; D009687:Nuclear Proteins / Q000235:genetics*; D051381:Rats; D012097:Repressor Proteins / Q000235:genetics*
C491304:ANKRD1 protein, human; D009124:Muscle Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins