Genetic testing of candidate genes in arrhythmogenic right ventricular cardiomyopathy/dysplasia

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a rare cardiac genetic disease characterized by the presence of structural alterations in the right ventricle which may cause ventricular arrhythmias and may induce sudden cardiac death. ARVC/D has been associated with mutations in genes encoding myocyte adhesion proteins. However, only 30%-50% of patients have mutations in these genes. Genetic testing is useful in obtaining a diagnosis, particularly in individuals who do not completely fulfill clinical criteria, thereby also enabling the undertaking of preventive strategies in family members. The main goal of this study was to identify mutations in candidate genes associated with intercalate disks that could be potentially involved in ARVC/D pathogenesis. We analyze a cohort of 14 Spanish unrelated patients clinically diagnosed with ARVC/D without any genetic alteration in all previously known responsible genes. Thus, a genetic screening has been performed in 7 additional potential candidate genes (ACTC1 -actin alpha cardiac muscle 1-, CDHN -cadherin 2 type 1 or N-cadherin-, CTNNA1 -catenin alpha 1-, Cx43 or GJA1 -gap junction protein alpha 1-, MVCL -Metavinculin-, MYL2 -myosin light chain 2- and MYL3 -myosin light chain 3-) by direct sequencing analysis. Our genetic analysis did not identify any disease-causing mutation. Thirty single nucleotides polymorphisms were found, six of them novel. In conclusion, our ARVC/D Spanish cohort has not shown any mutations in the analyzed candidate genes despite their involvement in formation and maintenance of the intercalated disk.

Detection of herpesvirus-like sequences in Kaposi's sarcoma from heart transplant recipients

BACKGROUND

Herpesvirus-like DNA sequences have been found in lesions from patients with Kaposi's sarcoma in its several forms, suggesting that this tumor may be caused by a new herpesvirus, referred to as Kaposi's sarcoma-associated herpesvirus or human herpesvirus 8.

METHODS

We analyzed DNA from skin and lung lesions, healthy skin, and peripheral blood mononuclear cells of three heart transplant recipients with Kaposi's sarcoma. We also studied DNA from normal skin and from peripheral blood of Kaposi's sarcoma-free heart transplant recipients. Samples were analyzed by polymerase chain reaction with specific primers to amplify the KS 330 sequence.

RESULTS

The KS 330 fragment was found in Kaposi's sarcoma tissue of all three patients, in normal skin of one of them, and in peripheral blood of two. It was not detected in any of the samples from skin or peripheral blood of heart transplant recipients not affected by Kaposi's sarcoma. DNA extracted from a peripheral blood sample of one patient before transplantation showed that the KS 330 sequence was already detectable at that time.

CONCLUSIONS

These findings suggest that Kaposi's sarcoma-associated herpesvirus may play a significant role in the pathogenesis of all forms of Kaposi's sarcoma. The development of the tumor in transplant recipients may be related, at least in some cases, to transplantation-associated immunosuppression, rather than to the acquisition of the virus from the donor.

Septic arthritis by Salmonella enteritidis after heart transplantation

A 13-year-old boy underwent orthotopic heart transplantation for end-stage idiopathic dilated cardiomyopathy. Immunosuppressive therapy consisted of cyclosporine, azathioprine, prednisone, and antithymocyte globulin. Endomyocardial biopsies revealed persistent moderate rejection, which was treated aggressively. In the sixth week, septic arthritis by Salmonella enteritidis developed. We discuss our management of this exceptional complication and the poor results obtained because of superimposed cytomegalovirus infection.