Michels

Clinical Report

 

Title: THE FREQUENCY OF FAMILIAL DILATED CARDIOMYOPATHY IN A SERIES OF PATIENTS WITH IDIOPATHIC DILATED CARDIOMYOPATHY.
Authors: Michels VV, Moll PP, Miller FA, Tajik J, Chu JS, Driscoll DJ, Burnett JC, Rodeheffer RJ, Chesebro JH, and Tazelaar HD.
Journal: New Engl J Med, 1992;326:77-82.
Department of Medical Genetics, Mayo Clinic, Rochester, Minn.
PubMed Link: PMID: 1727235
Citation Type: phenotype (clinical data only).
Study Design: prospective study of first degree relatives of patients with idiopathic dilated cardiomyopathy.
Study Measurements: echocardiography, ECG.
Summary: Virginia Michels and colleagues at the Mayo Clinic demonstrated that dilated cardiomyopathy was a familial disease in 20% of subjects diagnosed with IDC.  Inclusion criteria included an echocardiographic diastolic dimension >95th percentile for the patient’s age and body surface area and a left ventricular ejection fraction <50%.  All patients >40 years of age underwent coronary angiography to exclude coronary artery disease as the etiology of their dilated cardiomyopathy.  Ninety-six patients were identified by chart review and 59 (61%) agreed to participate and had their relatives enrolled for study.  A total of 315 relatives were prospectively screened.  Familial disease was shown to be present in 12 of these 59 index patients (20%), with 18 relatives found to be affected with disease.  Of these, 6 had symptoms and 12 were asymptomatic.  Fifteen patients were given new diagnoses (7 known to have heart disease, 8 with no previously known heart disease).  Of the 20% of individuals initially diagnosed with IDC who were eventually assigned to FDC, only 5% had been suspected of having familial disease based on family history alone.  Finally, 22 of 240 (9.2%) relatives with normal ejection fractions had increased left ventricular systolic and/or diastolic dimensions compared to 2 of 112 (1.8%) healthy control subjects (p < 0.02).  This finding indicated that asymptomatic left ventricular enlargement was the earliest marker for familial dilated cardiomyopathy.  Complex segregation analysis of the families suggested a single dominant locus with incomplete penetrance.
Comment: In 1992 this study provided the most compelling evidence that IDC could be familial, and likely genetic, is some proportion of cases of IDC.