ANKRD1, the gene encoding cardiac ankyrin repeat protein, is a novel dilated cardiomyopathy gene.

OBJECTIVES: We evaluated ankyrin repeat domain 1 (ANKRD1), the gene encoding cardiac ankyrin repeat protein (CARP), as a novel candidate gene for dilated cardiomyopathy (DCM) through mutation analysis of a cohort of familial or idiopathic DCM patients, based on the hypothesis that inherited dysfunction of mechanical stretch-based signaling is present in a subset of DCM patients. BACKGROUND: CARP, a transcription coinhibitor, is a member of the titin-N2A mechanosensory complex and translocates to the nucleus in response to stretch. It is up-regulated in cardiac failure and hypertrophy and represses expression of sarcomeric proteins. Its overexpression results in contractile dysfunction. METHODS: In all, 208 DCM patients were screened for mutations/variants in the coding region of ANKRD1 using polymerase chain reaction, denaturing high-performance liquid chromatography, and direct deoxyribonucleic acid sequencing. In vitro functional analyses of the mutation were performed using yeast 2-hybrid assays and investigating the effect on stretch-mediated gene expression in myoblastoid cell lines using quantitative real-time reverse transcription-polymerase chain reaction. RESULTS: Three missense heterozygous ANKRD1 mutations (P105S, V107L, and M184I) were identified in 4 DCM patients. The M184I mutation results in loss of CARP binding with Talin 1 and FHL2, and the P105S mutation in loss of Talin 1 binding. Intracellular localization of mutant CARP proteins is not altered. The mutations result in differential stretch-induced gene expression compared with wild-type CARP. CONCLUSIONS: ANKRD1 is a novel DCM gene, with mutations present in 1.9% of DCM patients. The ANKRD1 mutations may cause DCM as a result of disruption of the normal cardiac stretch-based signaling.

Antigenic variation in surface proteins of Trypanosoma cruzi (Chagas' disease)

Chagas' disease, a devastating illness in the Western Hemisphere, is caused by the protozoan parasite Trypanosoma cruzi. Transmission is via bloodsucking insect vectors, congenitally, or through blood transfusion and/or organ transplantation. A significant percentage of heart-related illnesses and deaths each year are attributable to the number of persons with Chagas' disease. Currently, there is no FDA-approved routine screening of the U.S. blood supply being conducted by blood banks. The only current commercial assays available for detection of Trypanosoma cruzi are based on South American isolates, which may differ antigenically from those found in the US. In this study, the assay used intact parasites as antigen in an ELISA-type assay. Therefore, serological differences presumably reflected variations in surface antigens. The basis of differential antibody binding to these antigens is unknown. In this study, biochemical characterization and genetic polymorphism analysis will be performed on three defined surface proteins of T. cruzi epimastigotes.^

AMERICAN TRYPANOSOMIASIS (CHAGAS') DISEASE - A STUDY OF FETO-MATERNAL MORBIDITY AND MORTALITY

The possibility of a relationship between American Trypanosomiasis (Chagas') disease and pregnancy outcome was analyzed measuring feto-maternal morbidity and mortality in a sample of 604 pregnant women and their offspring seen at the Hospital Universitario de Maternidad y Neonatologia in Cordoba, Argentina during 1979.^ A cross-sectional, "case-comparison" investigation was employed to determine the degree of risk between having a reactive chagasic serologic test and a negative pregnancy outcome as determined by abortion, stillbirth, and infant death prior to one week of age. Patients were selected using a dichotomous, 0-1 scale with either the presence or the absence of a reactive Machado-Guerreiro complement fixation serologic blood test result.^ The data obtained were analyzed using appropriate statistical techniques for measuring the comparisons between the case and control groups under various demographic and socioeconomic variables such as, age, marital status, educational attainment, and residence. Similarly, additional biological variables of birth order, maternal and fetal complications, and prematurity were examined.^ From the analysis of the data obtained in this investigation, no definite conclusions can be reached regarding the risk of having an unsuccessful pregnancy outcome in the presence of a reactive serologic finding because the study design was a cross-sectional one and the number of events were too few for an adequate analysis. Notwithstanding these limitations, the results obtained, after statistical adjustments were employed, demonstrated that women with a reactive test result were older, were of a higher parity, and were less educated. Marital status and residence were not significant variables. The risk of pregnancy wastage, however, was almost twice as frequent in the reactive group as in the non-reactive group of women. Statistically significant differences in maternal morbidity involved two complications, polyhydramnios and varicosities of the lower extremities and vulva; while in the newborn, infection was higher in infants whose mothers exhibited a reactive serologic test result.^ In summary, what this research study has shown is the need for engaging in a larger, longitudinal study for an in-depth exploration of feto-maternal morbidity and mortality--an investigation that would corraborate or refute the findings of this study.^

Seroprevalence of Chagas' disease in Texas among shelter dogs in Houston and the Rio Grande Valley region and its implication for human infection

Chagas’ disease, also called American Trypanosomiasis, is a vector-borne disease caused by the protozoan parasite Trypanosoma cruzi. T. cruzi is spread by triatomine insects, commonly referred to as ‘kissing bugs.’ After the insect takes a blood meal from its animal or human host, it usually defecates near the bite wound. The parasite is present in the feces, and when rubbed into the bite wound or mucous membranes by the host, infection ensues. Chagas’ disease is highly endemic in Central and South America where it originated. Many people in these endemic areas live in poor conditions surrounded by animals, mainly dogs, that can serve as a possible link to human infection. In Chagas’ endemic countries, dogs can be used as a sentinel to infer risk for human infection. In Texas, the prevalence of Chagas’ and risk for human infection is largely unknown. This study aimed to determine the prevalence of Chagas’ disease in shelter dogs in Houston, Texas and the Rio Grande Valley region by using an immunochromatographic assay (Chagas’ Stat-Pak) to test for the presence of T. cruzi antibodies. Of the 822 samples tested, 26 were found to be positive (3.2%). In both locations, Chagas’ prevalence increased over time. This study found that dogs, especially strays, can serve as sentinels for disease activity. Public health authorities can implement this strategy to understand the level of Chagas’ activity in a defined geographic area and prevent human infection.^