Familial cardiomyopathy

Hereditary dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a common and important cause of morbidity and mortality. Many factors can contribute to the development of this disorder, although most commonly the etiology is unexplained. However, recent studies in individuals with idiopathic DCM now reveal a heritable cause in 20-30% of individuals. Diverse modes of inheritance have been demonstrated, encompassing an autosomal dominant type (by far the most common), together with recessive and X-linked forms, and maternal inheritance through mitochondrial DNA. The hereditary forms of DCM (HDCM) predominantly affect the left ventricle, although inherited abnormalities affecting primarily the right ventricle also are described. HDCM may occur as a primary cardiomyopathy, or secondary to inherited systemic metabolic or neuromuscular disorders. The causative genes for primary HDCM of the autosomal dominant and recessive types have not yet been discovered, but the combination of family pedigree analysis and phenotyping by echocardiography, together with new genetic techniques, should now allow their identification. Knowledge of the gene or genes responsible for HDCM would improve diagnostic accuracy, facilitate genetic counseling, advance understanding of pathogenesis, and provide the starting point for new methods of treatment. Because of the frequently heritable nature of DCM, it is of great importance that a diligent search for all potentially affected family members be undertaken.

Frequency of familial nature of dilated cardiomyopathy and usefulness of cardiac transplantation in this subset

A familial etiology was identified on the basis of family history in 16 (8.75%) of 184 patients undergoing cardiac transplantation at Stanford for endstage dilated cardiomyopathy (DC). These 16 patients, from 11 families, included 5 sibling pairs. To help determine optimal management of such patients, their case histories and posttransplant courses were reviewed. Mean age of patients at presentation was 23 +/- 15 years. In sibling pairs, duration of symptoms from onset to diagnosis was 14 +/- 5 weeks for the first sibling, but only 4 +/- 2 weeks for the second. Progressive cardiac enlargement was documented radiographically in siblings of transplant recipients in 2 families before the onset of symptoms. The posttransplant course with regard to rejection incidence, infectious complications, coronary artery disease and malignancy was similar to that of the 168 patients with nonfamilial DC. Actuarial survival at 5 years after transplantation was 80%. Thirteen patients (including all sibling pairs) are alive 1 to 11 years after transplantation. Sepsis was the cause of death in 3 patients, occurring during the early postoperative period in 2 and following retransplantation for graft atherosclerosis 7 years after the initial transplant in the third patient. Thus, diagnosis of DC in childhood or adolescence mandates evaluation and surveillance of family members, because this disease can progress rapidly. The favorable results of cardiac transplantation for familial DC suggest that it should be promptly considered for such patients with end-stage disease.

X-linked dilated cardiomyopathy

To study the inheritance of idiopathic dilated cardiomyopathy, we investigated a large kindred in which 11 young male members had definite or possible evidence of the disorder. The five affected males for whom we had complete clinical data survived for 5 to 12 months after the onset of symptoms, which occurred early in life (ages 15 to 21 years). In six other males, clinical data were incomplete but suggested possible cardiomyopathy. Three mothers of affected males were given a diagnosis of definite, and two of possible, late-onset dilated cardiomyopathy. These women presented in their 40s with atypical chest pain, and progressive congestive heart failure developed gradually over a period of 10 or more years. X-linked inheritance of dilated cardiomyopathy is suggested in this family by the early onset in males, late onset in females, and no evidence of male-to-male transmission. The late onset of the disease in females, in contrast to the early onset in hemizygous males, is compatible with heterozygosity for the mutant allele. Since most cases of genetically lethal X-linked syndromes appear to be sporadic, for every case of "idiopathic" dilated cardiomyopathy in which X-linked inheritance can be confirmed from family information, it is possible that there are several nonfamilial cases due to a mutation at the same locus.

Autosomal recessive inheritance of idiopathic dilated cardiomyopathy in a Madeira Portuguese kindred

Cardiomyopathy is a heterogeneous disorder with numerous inherited and acquired causes. Familial, isolated, dilated cardiomyopathy is usually reported as being inherited in an autosomal dominant mode with variable penetrance and expressivity. In this paper we describe a form of autosomal recessively inherited, dilated, cardiomyopathy occurring in three members of a consanguineous Madeira Portuguese family. Following review of the literature, it appears that the autosomal recessive form of dilated cardiomyopathy is more common than previously reported.

Hypergonadotropic hypogonadism with congestive cardiomyopathy: an autosomal-recessive disorder?

We report on two sisters with ovarian dysgenesis and secondary hypergonadotropic hypogonadism and congestive cardiomyopathy. Their parents are first cousins. It is suggested that these are the main manifestations of a previously unreported autosomal-recessive syndrome.

A familial dilated cardiomyopathy associated with cataracts and hip-spine disease

A dilated cardiomyopathy was observed in two generations of a kindred, associated with articular disease and premature cataracts, a unique triad not previously described to our knowledge. The cardiomyopathy was characterized histologically by basophilic PAS-positive granulofilamentous deposits in the myocardium. The articular disease included hip joint degeneration, irregular intervertebral disks, and platyspondyly. The lenticular abnormalities may occur in young adults prior to other manifestations of the triad. Consanguinity was noted in the parents, and inheritance was most compatible with an autosomal recessive trait, with variable penetrance and expressivity.

Idiopathic familial myocardiopathy in three generations: a clinical and pathologic study

A peculiar non-hypertrophic myocardiopathy is described which occurred in three and possibly five generations of a single family. Clinical features included systolic murmurs, electrocardiographic abnormalities, and sudden cardiac death with a paucity of symptoms of cardiac dysfunction. Pathological studies in three generations showed a striking similarity of cardiac findings including globular and dilated ventricles, endocardial fibroelastosis, and mitral valve thickening. Myocardium in two showed basophilic degeneration and fibrosis. A retrospective genealogic analysis and a prospective clinical evaluation of living family members suggested an autosomal dominant mode of inheritance with variable penetrance. The cause of this heritable myocardiopathy is presumably a mutant gene; the biochemical defect to which the mutant gene gives rise remains unknown.

[Importance of inheritance in cardiomyopathies (author's transl)]

Inheritance plays an important role in the cardiomyopathies (i.e. dysfunction of the cardiac muscle of unknown origin). This especially has become obvious for the entity asymmetric septal hypertrophy of autosomal dominant inheritance (ASH), a cardiomyopaty with and without obstruction. But this is not the only type of cardiomyopathy of dominant transmittance as was shown by the demonstration of a kindred, in which echocardiographically no hypertrophy of the septum could be found. For it was not possible to find a uniformity for all the affected members of the kindred, for example a congestive course of the disease. Therefore it is suggested to name the disease without any prejudice "cardiomyopathy without asymmetric septal hypertrophy of dominant inheritance" to distinguish it from the "cardiomyopathy with asymetric septal hypertrophy of dominant inheritance". There also may occur a cardiomyopathy of autosomal recessive inheritance. This form could represent a large part of the "sporadic" cardiomyopathies and should challenge to search intensively for enzyme defects as a cause of the disease.

Familial occurrence of sinus bradycardia, short PR interval, intraventricular conduction defects, recurrent supraventricular tachycardia, and cardiomegaly

Four members of a family presenting with sinus bradycardia, a short P-R interval, intraventricular conduction defects, recurrent supraventricular tachycardia (SVT), syncope, and cardiomegaly had His bundle studies and were found to have markedly shortened A-H intervals (30 to 55 msec.) with normal H-V times (35 to 50 msec.). Right atrial pacing at rates as high as 170 to 215 per minute failed to increase the A-H or H-V intervals significantly. The data are compatible with the presence of an A-V nodal bypass tract (James bundle) or even complete absence of an A-V node. Ventricular pacing and spontaneous ventricular premature beats resulted in a short ventriculoatrial conduction time (110 msec.) suggesting that if A-V nodal bypass tracts exist, they are utilized in an antegrade and retrograde fashion. None of the features of WPW syndrome was present. The mechanism of syncope in the mother and daughter was intermittent third-degree heart block. Both went on to develop permanent complete heart block despite electrophysiologic studies demonstrating 1:1 A-V conduction at extremely rapid atrial pacing rates and both required implantation of permanent pacemakers. The mechanism of syncope in the two brothers was possibly marked sinus bradycardia, but transient complete heart block has not been ruled out. Permanent pacemaker therapy was recommended for both. The nature of the cardiomegaly, which was mild in three patients, is not known. Although not well documented, several maternal relatives have had enlarged hearts, SVT, complete heart block, and syncope.

Hypertrophic cardiomyopathy with unusual features in a family

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Hypertrophic subaortic stenosis with myocardial fibre degeneration

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