Sarcomere mutations in cardiomyopathy with left ventricular hypertrabeculation.
BACKGROUND
Mutations in the genes encoding sarcomere proteins have been associated with both hypertrophic and dilated cardiomyopathy. Recently, mutations in myosin heavy chain (MYH7), cardiac actin (ACTC), and troponin T (TNNT2) were associated with left ventricular noncompaction, a form of cardiomyopathy characterized with hypertrabeculation that may also include reduced function of the left ventricle.


RESULTS
We used clinically available genetic testing on 3 cases referred for evaluation of left ventricular dysfunction and noncompaction of the left ventricle and found that all 3 individuals carried sarcomere mutations. The first patient presented with neonatal heart failure and was referred for left ventricular noncompaction cardiomyopathy. Genetic testing found 2 different mutations in MYBPC3 in trans. The first mutation, 3776delA, Q1259fs, rendered a frame shift at 1259 of cardiac myosin-binding protein C and the second mutation was L1200P. The frameshift mutation was also found in this mother who displayed mild echocardiographic features of cardiomyopathy, with only subtle increase in trabeculation and an absence of hypertrophy. A second pediatric patient presented with heart failure and was found to carry a de novo MYH7 R369Q mutation. The third case was an adult patient with dilated cardiomyopathy referred for ventricular hypertrabeculation. This patient had a family history of congestive heart failure, including pediatric onset cardiomyopathy where 3 individuals in the family were found to have the MYH7 mutation R1250W.


CONCLUSIONS
Genetic testing should be considered for cardiomyopathy with hypertrabeculation.
Dellefave
Lisa M
LM
Department of Medicine, The University of Chicago, Chicago, Ill, USA.
Pytel
Peter
P
Mewborn
Stephanie
S
Mora
Bassem
B
Guris
Deborah L
DL
Fedson
Savitri
S
Waggoner
Darrel
D
Moskowitz
Ivan
I
McNally
Elizabeth M
EM
D024722:Cardiac Myosins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000235:genetics*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009154:Mutation; D018995:Myosin Heavy Chains / Q000235:genetics; D010375:Pedigree; D012518:Sarcomeres / Q000235:genetics*; D014463:Ultrasonography; D000099163:Myosin Binding Protein C
D024722:Cardiac Myosins; D002352:Carrier Proteins; D018995:Myosin Heavy Chains; D000099163:Myosin Binding Protein C; C501641:MYH7 protein, human