We analysed the architecture of cardiomyocyte nuclei lacking lamin A activity in three patients with dilated cardiomyopathy. The diagnosis was established on the basis of clinical and electrophysiological examinations, chest radiography and electrocardiography.
An ultrastructural study of affected cardiomyocytes showed dramatic alterations in nuclear distribution and organization affecting nuclear shape, lamina structure, chromatin and nuclear interior organization. The most specific hallmark of nuclei with lamin A deficiency was the reorganization of the nuclear interior, the appearance of a various number of mitochondria within the nuclear matrix, and focal or total lack of nuclear membrane.