Human mutational constraint as a tool to understand biology of rare and emerging bone marrow failure syndromes
BLOOD ADVANCES
Authors: Oved, Joseph H.; Babushok, Dania, V; Lambert, Michele P.; Wolfset, Nicole; Kowalska, M. Anna; Poncz, Mortimer; Karczewski, Konrad J.; Olson, Timothy S.
Abstract
Inherited bone marrow failure (IBMF) syndromes are rare blood disorders characterized by hematopoietic cell dysfunction and predisposition to hematologic malignancies. Despite advances in the understanding of molecular pathogenesis of these heterogeneous diseases, genetic variant interpretation, genotype-phenotype correlation, and outcome prognostication remain difficult. As new IBMF and other myelodysplastic syndrome (MDS) predisposition genes continue to be discovered (frequently in small kindred studies), there is an increasing need for a systematic framework to evaluate penetrance and prevalence of mutations in genes associated with IBMF phenotypes. To address this need, we analyzed population-based genomic data from >125 000 individuals in the Genome Aggregation Database for loss-of-function (LoF) variants in 100 genes associated with IBMF. LoF variants in genes associated with IBMF/MDS were present in 0.426% of individuals. Heterozygous LoF variants in genes in which haploinsufficiency is associated with IBMF/MDS were identified in 0.422% of the population; homozygous LoF variants associated with autosomal recessive IBMF/MDS diseases were identified in only.004% of the cohort. Using age distribution of LoF variants and 2 measures of mutational constraint, LOEUF ("loss-of-function observed/expected upper bound fraction") and pLI ("probability of being loss-of-function intolerance"), we evaluated the pathogenicity, tolerance, and age-related penetrance of LoF mutations in specific genes associated with IBMF syndromes. This analysis led to insights into rare IBMF diseases, including syndromes associated with DHX34, MDM4, RAD51, SRP54, and WIPF1. Our results provide an important population-based framework for the interpretation of LoF variant pathogenicity in rare and emerging IBMF syndromes.
TRANSCRIPTIONAL PROFILE CHARACTERIZATION FOR THE IDENTIFICATION OF PERIPHERAL BLOOD BIOMARKERS IN PATIENTS WITH CEREBRAL ANEURYSMS
JOURNAL OF BIOLOGICAL REGULATORS AND HOMEOSTATIC AGENTS
Authors: Sabatino, G.; Rigante, L.; Minella, D.; Novelli, G.; Della Pepa, G. M.; Esposito, G.; Albanese, A.; Maira, G.; Marchese, E.
Abstract
We tried to identify molecular markers in peripheral blood to predict high risk of aneurysm rupture. Extraction of the total population of peripheral blood mononuclear cell (PBMC) from total blood volume, total RNA extraction from PBMC and Agilent One Color Gene-expression Oligo-Microarray were performed on peripheral venous blood samples from 45 patients with ruptured, unruptured cerebral aneurysms and control group (15). Mean foreground/ background signal intensities and A (log2(R*G)/2) values were calculated for each spot. Genes with absolute fold change (FC) >= +/- 1.5 and p-value < 0.05 were considered differentially expressed in the 3 groups (Student T-test). Genes coding for MMPs were strongly underexpressed in ruptured aneurysms group, suggesting a possible role in aneurysms development more than their rupture. Genes coding for adhesine proteins of the extracellular matrix (ICAM1) and cytoskeleton (WIPF1,TUBA4A) were underexpressed in ruptured aneurysms. Genes coding proteins involved in the regulation of apoptotic processes may be important in aneurysm development and rupture, resulting into an increased rate of remodeling processes in the arterial wall. Fas coding gene, SUM01, ZFAT, BCL2, CCR5 genes were all over-represented in unruptured aneurysms. The coexisting over-representation of pro-apoptotic genes and the underexpression of cytoskeleton and extracellular matrix genes confirms that aneurysms development and evolution are part of a degenerative process of the arterial wall not involved in aneurysms rupture. MMPs may be involved in repairing chronic damages to the arterial walls and preventing SAH. Unexpectedly, Heat Shock Proteins (HSP90AA1, HSPA1A, HSPB1), G and RAS proteins, generally activated by stress situations were under-represented in aneurysmal walls. Further PCR and Western Blotting studies are needed to confirm such findings and to identify diagnostic and prognostic markers in order to define screening protocols for intracranial aneurysms.