Identification of an elusive spliceogenic MYBPC3 variant in an otherwise genotype-negative hypertrophic cardiomyopathy pedigree.

The finding of a genotype-negative hypertrophic cardiomyopathy (HCM) pedigree with several affected members indicating a familial origin of the disease has driven this study to discover causative gene variants. Genetic testing of the proband and subsequent family screening revealed the presence of a rare variant in the MYBPC3 gene, c.3331-26T>G in intron 30, with evidence supporting cosegregation with the disease in the family. An analysis of potential splice-altering activity using several splicing algorithms consistently yielded low scores. Minigene expression analysis at the mRNA and protein levels revealed that c.3331-26T>G is a spliceogenic variant with major splice-altering activity leading to undetectable levels of properly spliced transcripts or the corresponding protein. Minigene and patient mRNA analyses indicated that this variant induces complete and partial retention of intron 30, which was expected to lead to haploinsufficiency in carrier patients. As most spliceogenic MYBPC3 variants, c.3331-26T>G appears to be non-recurrent, since it was identified in only two additional unrelated probands in our large HCM cohort. In fact, the frequency analysis of 46 known splice-altering MYBPC3 intronic nucleotide substitutions in our HCM cohort revealed 9 recurrent and 16 non-recurrent variants present in a few probands (≤ 4), while 21 were not detected. The identification of non-recurrent elusive MYBPC3 spliceogenic variants that escape detection by in silico algorithms represents a challenge for genetic diagnosis of HCM and contributes to solving a fraction of genotype-negative HCM cases.

Infective endocarditis after transcatheter aortic valve implantation: Contributions of a single-centre experience on incidence and associated factors. / Endocarditis infecciosa después de TAVI: aportaciones de la experiencia en un único centro sobre la incidencia y los factores asociados.

INTRODUCTION: Infective endocarditis (IE) after transcatheter aortic valve implantation (TAVI) is an emerging complication. There are incomplete and disparate data on its incidence. We present the experience of a single-centre of incidence, mortality and associated factors of IE after TAVI. METHODS: A retrospective observational study of IE cases in people who received a TAVI, between 06/01/2009 and 11/01/2017, in a university hospital, during a median follow-up period of 15.3months (interquartile range [IQR] 9.1-36.2). Incidence, clinical, microbiological and prognostic data, and factors associated with IE after TAVI were analysed. RESULTS: Eleven patients with IE of 200 TAVI were detected. Global incidence: 5.5% (2.77 cases per 100 patient-year). The median of days from TAVI to IE was 112 (IQR 36-578), the in-hospital mortality rate was 36.4%, and the one-year mortality rate was 54.5%. All the organisms identified were gram-positive (4 Enterococcus faecalis, 3 coagulase-negative Staphylococcus). The patients with IE after TAVI were significantly younger (median 78years, IQR 73-80, versus 82 years, IQR 79-84, P=.002), they had a higher EuroSCORE (5.1±2.4 versus 3.2±1.2, P<.001), and they more frequently had a history of neoplasia (18.2% versus 4.2%, P<.03) CONCLUSIONS: In our area, IE after TAVI has an incidence greater than that described in multicentre series, this is in line with the trend published in the literature. It leads to high mortality and is associated with a worse baseline clinical situation.