Diagnostic yield of molecular autopsy in patients with sudden arrhythmic death syndrome using targeted exome sequencing.

AIMS: The targeted genetic screening of Sudden Arrhythmic Death Syndrome (SADS) probands in a molecular autopsy has a diagnostic yield of up to 35%. Exome sequencing has the potential to improve this yield. The primary aim of this study is to examine the feasibility and diagnostic utility of targeted exome screening in SADS victims, utilizing familial clinical screening whenever possible. METHODS AND RESULTS: To determine the feasibility and diagnostic yield of targeted exome sequencing deoxyribonucleic acid (DNA) was isolated from 59 SADS victims (mean age 25 years, range 1-51 years). Targeted exome sequencing of 135 genes associated with cardiomyopathies and ion channelopathies was performed on the Illumina HiSeq2000 platform. Non-synonymous, loss-of-function, and splice-site variants with a minor allele frequency <0.02% in the NHLBI exome sequencing project and an internal set of control exomes were prioritized for analysis followed by <0.5% frequency threshold secondary analysis. First-degree relatives were offered clinical screening for inherited cardiac conditions. Seven probands (12%) carried very rare (<0.02%) or novel non-sense candidate mutations and 10 probands (17%) had previously published rare (0.02-0.5%) candidate mutations-a total yield of 29%. Co-segregation fully confirmed two private SCN5A Na channel mutations. Variants of unknown significance were detected in a further 34% of probands. CONCLUSION: Molecular autopsy using targeted exome sequencing has a relatively low diagnostic yield of very rare potentially disease causing mutations. Candidate pathogenic variants with a higher frequency in control populations are relatively common and should be interpreted with caution.

Illness perceptions, affective response, and health-related quality of life in patients with atrial fibrillation.

OBJECTIVE: The purpose of this study was to determine how health-related quality of life (HRQoL), depression, and anxiety change over the first 12 months following diagnosis of atrial fibrillation (AF). In addition, we also aimed to investigate whether illness perceptions and beliefs about medication at the time of diagnosis are associated with HRQoL and affective response over time. METHODS: Seventy patients [mean (S.D.) age of 71.4 (9.1) years; 45 (64.3%) were men] with 'lone' AF completed the Beck Depression Inventory Short Form (BDI-SF-13), State-Trait Anxiety Inventory (STAI), Perceived Stress Scale (PSS), Short-Form Medical Outcomes Survey (SF-36), Illness Perception Questionnaire, and Beliefs about Medication Questionnaire at baseline and the BDI-SF-13, STAI, PSS, and SF-36 at 6 and 12 months after diagnosis of AF. RESULTS: Lone AF patients reported few depressive symptoms, while anxiety symptoms predominated, with a prevalence of elevated state anxiety (STAI-S > or =40) of 38.5%, 30.9%, and 35.7% at baseline and at 6 and 12 months, respectively. There were no significant differences in the levels of depression and mean levels of state and trait anxiety, perceived stress, and HRQoL (except for an increase in energy and decline in general health perception) over time. Baseline state and trait anxiety afforded the best prediction of state anxiety trajectory over 12 months (42% and 5%, respectively). The number of symptoms patients perceived as attributable to AF and specific concerns relating to their medication, at baseline, were independent predictors of physical health trajectories over 12 months after adjustment for age, gender, and AF type (P=.01) and together accounted for 15% of the variance in the slope. CONCLUSION: Anxiety appears to be the main affective response to diagnosis of AF in a cohort of patients without other associated comorbidities. Patients' perceptions of their symptoms and concerns about the necessity of medication at diagnosis should be specifically addressed as part of their medical management.

Is chromosome radiosensitivity and apoptotic response to irradiation correlated with cancer susceptibility?

PURPOSE: Individuals who have been treated for breast cancer have been reported to have increased lymphocyte chromosomal sensitivity to ionizing radiation and a significantly lower apoptotic response to irradiation compared to controls. We set out to test these findings using a substantial number of cases sampled before treatment (which could alter the parameters measured), compared to age-matched controls with normal mammograms. MATERIAL AND METHODS: We used the G2 chromosome breakage, and apoptotic response assays of peripheral blood lymphocytes to ionizing radiation to compare 211 unselected newly diagnosed and untreated breast cancer patients, with 170 age, sex and ethnically matched controls. RESULTS: We found no significant differences between breast cancer patients and their matched controls in the G2 assay or apoptotic response. However, there was some evidence that both cases and controls with a strong family history of breast cancer had higher radiosensitivity than those without. CONCLUSIONS: This is the largest and best controlled study of its kind, but it has not replicated previous reports of differences between chromosome breakage or apoptotic response in breast cancer cases vs. controls. However there was a suggestion of increased radiosensitivity in patients with a strong family history, which may indicate a heritable cancer susceptibility trait, warranting further study.

Lymphocyte radiosensitivity in BRCA1 and BRCA2 mutation carriers and implications for breast cancer susceptibility.

There is conflicting evidence as to whether individuals who are heterozygous for germ-line BRCA1 or BRCA2 mutations have an altered phenotypic cellular response to irradiation. To investigate this, chromosome breakage and apoptotic response were measured after irradiation in peripheral blood lymphocytes from 26 BRCA1 and 18 BRCA2 mutation carriers without diagnosed breast cancer, and 38 unaffected age, ethnically and sex-matched controls. To assess the role of BRCA1 and BRCA2 in homologous recombination, an S phase enrichment chromosome breakage assay was used. BrdUrd incorporation studies allowed verification of the correct experimental settings. We found that BRCA1 mutation carriers without cancer had increased chromosome breaks as well as breaks and gaps per cell post irradiation using the classical G2 assay (p = 0.01 and 0.004, respectively) and the S phase enrichment assay (p = 0.01 and 0.01, respectively) compared to age-matched unaffected controls. BRCA2 mutation carriers without cancer had increased breaks as well as breaks and gaps per cell post irradiation using the S phase enrichment assay (p = 0.045 and 0.012, respectively). No difference was detected using the G2 assay (p = 0.88 and 0.40 respectively). BRCA1 and BRCA2 mutation carriers had normal cell cycle kinetics and apoptotic response to irradiation compared to age-matched controls. Our results show a demonstrable impairment in irradiation induced DNA repair in women with heterozygous germline BRCA1 and BRCA2 mutations prior to being diagnosed with breast cancer.