Mutations in ribonucleic acid binding protein gene cause familial dilated cardiomyopathy.
OBJECTIVE
We sought to identify a novel gene for dilated cardiomyopathy (DCM).


BACKGROUND
DCM is a heritable, genetically heterogeneous disorder that remains idiopathic in the majority of patients. Familial cases provide an opportunity to discover unsuspected molecular bases of DCM, enabling pre-clinical risk detection.


METHODS
Two large families with autosomal-dominant DCM were studied. Genome-wide linkage analysis was used to identify a disease locus, followed by fine mapping and positional candidate gene sequencing. Mutation scanning was then performed in 278 unrelated subjects with idiopathic DCM, prospectively identified at the Mayo Clinic.


RESULTS
Overlapping loci for DCM were independently mapped to chromosome 10q25-q26. Deoxyribonucleic acid sequencing of affected individuals in each family revealed distinct heterozygous missense mutations in exon 9 of RBM20, encoding ribonucleic acid (RNA) binding motif protein 20. Comprehensive coding sequence analyses identified missense mutations clustered within this same exon in 6 additional DCM families. Mutations segregated with DCM (peak composite logarithm of the odds score >11.49), were absent in 480 control samples, and altered residues within a highly conserved arginine/serine (RS)-rich region. Expression of RBM20 messenger RNA was confirmed in human heart tissue.


CONCLUSIONS
Our findings establish RBM20 as a DCM gene and reveal a mutation hotspot in the RS domain. RBM20 is preferentially expressed in the heart and encodes motifs prototypical of spliceosome proteins that regulate alternative pre-messenger RNA splicing, thus implicating a functionally distinct gene in human cardiomyopathy. RBM20 mutations are associated with young age at diagnosis, end-stage heart failure, and high mortality.
Brauch
Katharine M
KM
Cardiovascular Genetics Laboratory, College of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
Karst
Margaret L
ML
Herron
Kathleen J
KJ
de Andrade
Mariza
M
Pellikka
Patricia A
PA
Rodeheffer
Richard J
RJ
Michels
Virginia V
VV
Olson
Timothy M
TM
D000293:Adolescent; D000328:Adult; D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000235:genetics* / Q000378:metabolism; D002675:Child, Preschool; D005260:Female; D008040:Genetic Linkage; D055106:Genome-Wide Association Study; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D008126:Lod Score; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D009206:Myocardium / Q000378:metabolism; D010375:Pedigree; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics*; D017381:Spliceosomes / Q000235:genetics; D055815:Young Adult
D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C543725:ribonucleic acid binding motif protein 20, human