A novel founder MSH2 deletion in Ethiopian Jews is mainly associated with early-onset colorectal cancer

Lynch syndrome is an inherited cancer predisposition syndrome caused by germline defects in any of the mismatch repair (MMR) genes. Diagnosis of carriers makes precision prevention, early detection, and tailored treatment possible. Herein we report a novel founder deletion of 18,758 bp, mediated by Alu repeats on both sides, detected in Ethiopian Jews. The deletion, which encompasses exon 9-10 of the MSH2 coding sequence, is associated mainly with early-onset MSH2/MSH6-deficient colorectal cancer (CRC) and liposarcoma. Testing of 35 members of 5 seemingly unrelated families of Ethiopian origin yielded 10/21 (48%) carriers, of whom 9 had CRC. Age at first tumor diagnosis ranged from 16 to 89 years. Carriers from the oldest generations were diagnosed after age 45 years (mean 57), and carriers from the younger generation were diagnosed before age 45 years (mean 30). Awareness of this founder deletion is important to improve patient diagnosis, institute surveillance from an early age, and refer patients for genetic counseling addressing the risk of bi-allelic constitutional MMR deficiency syndrome.

Circulating microRNAs and sudden cardiac arrest outcomes

AIM

MicroRNAs (miRNAs) have regulatory functions in organs critical in resuscitation from sudden cardiac arrest due to ventricular fibrillation (VF-SCA); therefore, circulating miRNAs may be markers of VF-SCA outcome.

METHODS

We measured candidate miRNAs (N=45) in plasma using qRT-PCR among participants of a population-based VF-SCA study. Participants were randomly selected cases who died in the field (DF, n=15), died in hospital (DH, n=15), or survived to discharge (DC, n=15), and, age-, sex-, and race-matched controls (n=15). MiRNA levels were compared using ANOVA, t-tests, and fold-changes.

RESULTS

Mean age of groups ranged from 66.9 to 69.7. Most participants were male (53-67%) and white (67%). Comparing cases to controls, plasma levels of 17 miRNAs expressed in heart, brain, liver, and other tissues (including miR-29c, -34a, -122, -145, -200a, -210, -499-5p, and -663b) were higher and three non-specific miRNAs lower (miR-221, -330-3p, and -9-5p). Among DH or DC compared with DF cases, levels of two miRNAs (liver-specific miR-122 and non-specific miR-205) were higher and two heart-specific miRNAs (miR-208b and -499-5p) lower. Among DC vs. DF cases, levels of three miRNAs (miR-122, and non-specific miR-200a and -205) were higher and four heart-specific miRNAs (miR-133a, -133b, -208b, and -499-5p) lower. Among DC vs. DH cases, levels of two non-specific miRNAs (miR-135a and -9-3p) were lower.

CONCLUSIONS

Circulating miRNAs expressed in heart, brain, and other tissues differ between VF-SCA cases and controls and are related to resuscitation outcomes. Measurement of miRNAs may clarify mechanisms underlying resuscitation, improve prognostication, and guide development of therapies. Results require replication.

Project normal: defining normal variance in mouse gene expression

The mouse has become an indispensable and versatile model organism for the study of development, genetics, behavior, and disease. The application of comprehensive gene expression profiling technologies to compare normal and diseased tissues or to assess molecular alterations resulting from various experimental interventions has the potential to provide highly detailed qualitative and quantitative descriptions of these processes. Ideally, to interpret experimental data, the magnitude and diversity of gene expression for the system under study should be well characterized, yet little is known about the normal variation of mouse gene expression in vivo. To assess natural differences in murine gene expression, we used a 5406-clone spotted cDNA microarray to quantitate transcript levels in the kidney, liver, and testis from each of 6 normal male C57BL6 mice. We used ANOVA to compare the variance across the six mice to the variance among four replicate experiments performed for each mouse tissue. For the 6 kidney samples, 102 of 3,088 genes (3.3%) exhibited a statistically significant mouse variance at a level of 0.05. In the testis, 62 of 3,252 genes (1.9%) showed statistically significant variance, and in the liver, there were 21 of 2,514 (0.8%) genes with significantly variable expression. Immune-modulated, stress-induced, and hormonally regulated genes were highly represented among the transcripts that were most variable. The expression levels of several genes varied significantly in more than one tissue. These studies help to define the baseline level of variability in mouse gene expression and emphasize the importance of replicate microarray experiments.