Just 2% of SARS-CoV-2-positive individuals carry 90% of the virus circulating in communities.

We analyze data from the fall 2020 pandemic response efforts at the University of Colorado Boulder, where more than 72,500 saliva samples were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using qRT-PCR. All samples were collected from individuals who reported no symptoms associated with COVID-19 on the day of collection. From these, 1,405 positive cases were identified. The distribution of viral loads within these asymptomatic individuals was indistinguishable from what has been previously observed in symptomatic individuals. Regardless of symptomatic status, ∼50% of individuals who test positive for SARS-CoV-2 seem to be in noninfectious phases of the disease, based on having low viral loads in a range from which live virus has rarely been isolated. We find that, at any given time, just 2% of individuals carry 90% of the virions circulating within communities, serving as viral "supercarriers" and possibly also superspreaders.

Interpretation and reporting of large regions of homozygosity and suspected consanguinity/uniparental disomy, 2021 revision: A technical standard of the American College of Medical Genetics and Genomics (ACMG).

Genomic testing, including single-nucleotide variation (formerly single-nucleotide polymorphism)-based chromosomal microarray and exome and genome sequencing, can detect long regions of homozygosity (ROH) within the genome. Genomic testing can also detect possible uniparental disomy (UPD). Platforms that can detect ROH and possible UPD have matured since the initial American College of Medical Genetics and Genomics (ACMG) standard was published in 2013, and the detection of ROH and UPD by these platforms has shown utility in diagnosis of patients with genetic/genomic disorders. The presence of these segments, when distributed across multiple chromosomes, may indicate a familial relationship between the proband's parents. This technical standard describes the detection of possible consanguinity and UPD by genomic testing, as well as the factors confounding the inference of a specific parental relationship or UPD. Current bioethical and legal issues regarding detection and reporting of consanguinity are also discussed.

Higher Viral Load Drives Infrequent Severe Acute Respiratory Syndrome Coronavirus 2 Transmission Between Asymptomatic Residence Hall Roommates.

BACKGROUND: The coronavirus disease 2019 pandemic spread to >200 countries in <6 months. To understand coronavirus spread, determining transmission rate and defining factors that increase transmission risk are essential. Most cases are asymptomatic, but people with asymptomatic infection have viral loads indistinguishable from those in symptomatic people, and they do transmit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, asymptomatic cases are often undetected. METHODS: Given high residence hall student density, the University of Colorado Boulder established a mandatory weekly screening test program. We analyzed longitudinal data from 6408 students and identified 116 likely transmission events in which a second roommate tested positive within 14 days of the index roommate. RESULTS: Although the infection rate was lower in single-occupancy rooms (10%) than in multiple-occupancy rooms (19%), interroommate transmission occurred only about 20% of the time. Cases were usually asymptomatic at the time of detection. Notably, individuals who likely transmitted had an average viral load approximately 6.5-fold higher than individuals who did not (mean quantification cycle [Cq], 26.2 vs 28.9). Although students with diagnosed SARS-CoV-2 infection moved to isolation rooms, there was no difference in time to isolation between cases with or without interroommate transmission. CONCLUSIONS: This analysis argues that interroommate transmission occurs infrequently in residence halls and provides strong correlative evidence that viral load is proportional to transmission probability.

Repetitive element transcripts are elevated in the brain of C9orf72 ALS/FTLD patients.

Significant transcriptome alterations are detected in the brain of patients with amyotrophic lateral sclerosis (ALS), including carriers of the C9orf72 repeat expansion and C9orf72-negative sporadic cases. Recently, the expression of repetitive element transcripts has been associated with toxicity and, while increased repetitive element expression has been observed in several neurodegenerative diseases, little is known about their contribution to ALS. To assess whether aberrant expression of repetitive element sequences are observed in ALS, we analysed RNA sequencing data from C9orf72-positive and sporadic ALS cases, as well as healthy controls. Transcripts from multiple classes and subclasses of repetitive elements (LINEs, endogenous retroviruses, DNA transposons, simple repeats, etc.) were significantly increased in the frontal cortex of C9orf72 ALS patients. A large collection of patient samples, representing both C9orf72 positive and negative ALS, ALS/FTLD, and FTLD cases, was used to validate the levels of several repetitive element transcripts. These analyses confirmed that repetitive element expression was significantly increased in C9orf72-positive compared to C9orf72-negative or control cases. While previous studies suggest an important link between TDP-43 and repetitive element biology, our data indicate that TDP-43 pathology alone is insufficient to account for the observed changes in repetitive elements in ALS/FTLD. Instead, we found that repetitive element expression positively correlated with RNA polymerase II activity in postmortem brain, and pharmacologic modulation of RNA polymerase II activity altered repetitive element expression in vitro. We conclude that increased RNA polymerase II activity in ALS/FTLD may lead to increased repetitive element transcript expression, a novel pathological feature of ALS/FTLD.

TDP-1, the Caenorhabditis elegans ortholog of TDP-43, limits the accumulation of double-stranded RNA.

Caenorhabditis elegans mutants deleted for TDP-1, an ortholog of the neurodegeneration-associated RNA-binding protein TDP-43, display only mild phenotypes. Nevertheless, transcriptome sequencing revealed that many RNAs were altered in accumulation and/or processing in the mutant. Analysis of these transcriptional abnormalities demonstrates that a primary function of TDP-1 is to limit formation or stability of double-stranded RNA. Specifically, we found that deletion of tdp-1: (1) preferentially alters the accumulation of RNAs with inherent double-stranded structure (dsRNA); (2) increases the accumulation of nuclear dsRNA foci; (3) enhances the frequency of adenosine-to-inosine RNA editing; and (4) dramatically increases the amount of transcripts immunoprecipitable with a dsRNA-specific antibody, including intronic sequences, RNAs with antisense overlap to another transcript, and transposons. We also show that TDP-43 knockdown in human cells results in accumulation of dsRNA, indicating that suppression of dsRNA is a conserved function of TDP-43 in mammals. Altered accumulation of structured RNA may account for some of the previously described molecular phenotypes (e.g., altered splicing) resulting from reduction of TDP-43 function.

Novel de novo pathogenic variant in the NR2F2 gene in a boy with congenital heart defect and dysmorphic features.

The NR2F2 gene plays an important role in angiogenesis and heart development. Moreover, this gene is involved in organogenesis in many other organs in mouse models. Variants in this gene have been reported in a number of patients with nonsyndromic atrioventricular septal defect, and in one patient with congenital heart defect and dysmorphic features. Here we report an 11-month-old Caucasian male with global developmental delay, dysmorphic features, coarctation of the aorta, and ventricular septal defect. He was later found to have a pathogenic mutation in the NR2F2 gene by whole exome sequencing. This is the second instance in which an NR2F2 mutation has been identified in a child with a congenital heart defect and other anomalies. This case suggests that some variants in NR2F2 may cause syndromic forms of congenital heart defect.

A previously unrecognized 22q13.2 microdeletion syndrome that encompasses TCF20 and TNFRSF13C.

Phelan-McDermid syndrome (PMS, OMIM 606232) is a heterozygous contiguous gene microdeletion syndrome occurring at the distal region of chromosome 22q13. This deletion encompasses the SHANK3 gene at 22q13.33, which is thought to be the critical gene for the neurodevelopmental features seen in this syndrome. PMS is typically characterized by intellectual disability, autism spectrum disorder, absent to severely delayed speech, neonatal hypotonia, and dysmorphic features. Two patients presenting with classic clinical features of PMS have been reported to have interstitial microdeletions in the 22q13.2 region that map proximal to the SHANK3 gene (0.54 and 0.72 Mb, respectively). Here, we describe a 13-month-old girl with a de novo 1.16 Mb interstitial deletion in the 22q13.2 region who presented with global developmental delay, subtle dysmorphic features, and immunodeficiency. This deletion overlaps with the two previously published cases and five cases from the DECIPHER database. All eight patients share features common to patients with PMS including developmental delay and language delay, which suggests that this represents a previously unrecognized microdeletion syndrome in the 22q13.2 region. Our patient's deletion encompasses the TCF20 and TNFRSF13C genes, which are thought to play causative roles in the patient's neurodevelopmental and immunological features, respectively.

Allogeneic Hematopoietic Stem Cell Transplantation Is Underutilized in Older Patients with Myelodysplastic Syndromes.

Allogeneic hematopoietic stem cell transplantation (HCT) is the only curative treatment for myelodysplastic syndrome (MDS). The proportion of MDS patients referred for transplantation evaluation, those undergoing transplantation, and the reasons for not undergoing transplantation are unknown. In this retrospective analysis, predefined HCT eligibility and indications criteria were applied to 362 unselected patients with newly diagnosed MDS seen by leukemia faculty between 2008 and 2015 at Memorial Sloan Kettering Cancer Center. Two hundred ninety-four patients (81%) were deemed eligible for transplantation and among these, transplantation was considered indicated in 244 (83%). Of these, 158 of 244 (65%) were referred for transplantation evaluation at a median of 3.9 months from diagnosis. Overall 120 of 362 (33%) underwent transplantation at a median of 7.7 months from diagnosis. Metastatic solid-organ malignancy was the major reason for transplantation ineligibility (54%), and death due to MDS, which occurred in 41% of candidates who did not undergo transplantation, was the major reason for not undergoing transplantation. Factors associated with a lower likelihood of referral for transplantation evaluation included age ≥65 (P < .001), ≥2 comorbidities (P = .008), intermediate-1/low risk MDS (P < .001), <5% blasts at diagnosis (overall P < .001), having Medicare/Medicaid health insurance (P < .001), not being married (P = .017), and diagnosis between 2008 and 2011 (P = .035). On multivariate analysis adjusting for all of the previous factors, diagnosis between 2008 and 2011 (P < .001), age ≥65 (P = .001), and <5% blasts at diagnosis (overall P = .031) were associated with a lower likelihood of referral for transplantation evaluation. Factors associated with a lower likelihood of undergoing transplantation included age ≥65 (P < .001), ≥2 comorbidities (P = .003), intermediate-1/low risk MDS (P < .001), <5% blasts (overall P < .001), very low/low/intermediate risk International Prognostic Scoring System-revised karyotype (P = .018), and having Medicare/Medicaid health insurance (P < .001). In multivariate analysis adjusting for all of the previous factors, age ≥65 (P = .021), presence of ≥2 comorbidities (P = .018), and <5% blasts (overall P = .011) were associated with a lower likelihood of undergoing transplantation. The results highlight that transplantation for MDS remains underutilized, particularly for candidates over the age of 65.

Synergistic, collaterally sensitive ß-lactam combinations suppress resistance in MRSA.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent multidrug-resistant pathogens worldwide, exhibiting increasing resistance to the latest antibiotic therapies. Here we show that the triple ß-lactam combination meropenem-piperacillin-tazobactam (ME/PI/TZ) acts synergistically and is bactericidal against MRSA subspecies N315 and 72 other clinical MRSA isolates in vitro and clears MRSA N315 infection in a mouse model. ME/PI/TZ suppresses evolution of resistance in MRSA via reciprocal collateral sensitivity of its constituents. We demonstrate that these activities also extend to other carbapenem-penicillin-ß-lactamase inhibitor combinations. ME/PI/TZ circumvents the tight regulation of the mec and bla operons in MRSA, the basis for inducible resistance to ß-lactam antibiotics. Furthermore, ME/PI/TZ subverts the function of penicillin-binding protein-2a (PBP2a) via allostery, which we propose as the mechanism for both synergy and collateral sensitivity. Showing in vivo activity similar to that of linezolid, ME/PI/TZ demonstrates that combinations of older ß-lactam antibiotics could be effective against MRSA infections in humans.

Familial isolated clubfoot is associated with recurrent chromosome 17q23.1q23.2 microduplications containing TBX4.

Clubfoot is a common musculoskeletal birth defect for which few causative genes have been identified. To identify the genes responsible for isolated clubfoot, we screened for genomic copy-number variants with the Affymetrix Genome-wide Human SNP Array 6.0. A recurrent chromosome 17q23.1q23.2 microduplication was identified in 3 of 66 probands with familial isolated clubfoot. The chromosome 17q23.1q23.2 microduplication segregated with autosomal-dominant clubfoot in all three families but with reduced penetrance. Mild short stature was common and one female had developmental hip dysplasia. Subtle skeletal abnormalities consisted of broad and shortened metatarsals and calcanei, small distal tibial epiphyses, and thickened ischia. Several skeletal features were opposite to those described in the reciprocal chromosome 17q23.1q23.2 microdeletion syndrome associated with developmental delay and cardiac and limb abnormalities. Of note, during our study, we also identified a microdeletion at the locus in a sibling pair with isolated clubfoot. The chromosome 17q23.1q23.2 region contains the T-box transcription factor TBX4, a likely target of the bicoid-related transcription factor PITX1 previously implicated in clubfoot etiology. Our result suggests that this chromosome 17q23.1q23.2 microduplication is a relatively common cause of familial isolated clubfoot and provides strong evidence linking clubfoot etiology to abnormal early limb development.

Drosophila Arc1 is not required for male fertility or sperm competition success.

Activity-regulated cytoskeleton associated protein (Arc1), which is required for synaptic plasticity and metabolism in Drosophila , self-assembles into capsid-like structures that transport mRNAs in extracellular vesicles. In addition to expression in the brain and nervous system, Arc1 is expressed in the male accessory glands, an endothelial tissue that produces male seminal proteins and exosomes that impact male fertility. We thus hypothesized that Arc1 might impact male fertility. We measured the fertility, mating latency, mating duration, and sperm competition performance of Arc1 males relative to controls and found no evidence that Arc1 is required for any of these measures of male fertility.

Morphologic, immunophenotypic, molecular genetic, and clinical characterization in patients with SRSF2-mutated acute myeloid leukemia.

OBJECTIVES: SRSF2 mutations are known to be associated with poor outcomes in myelodysplastic neoplasm, but studies on their prognostic impact on acute myeloid leukemia (AML) remain limited. In this retrospective study, we analyzed clinical and pathologic characteristics of patients with AML and correlated the outcomes with SRSF2 mutations. METHODS: We characterized the morphologic, immunophenotypic, molecular, and clinical findings in AML with mutated SRSF2 and compared them with SRSF2 wild-type (WT) myeloid neoplasms (MNs). RESULTS: Using next-generation sequencing, we identified 134 patients with MNs and SRSF2 mutations (85 with AML and 49 with MNs) in addition to 342 SRSF2-WT AMLs. Fifty-two (62%) patients with altered SRSF2 demonstrated a variable degree of morphologic dysplasia. The most frequent immunophenotypic aberrancies in SRSF2-mutant AML included diminished CD33 expression and overexpression of CD7, CD56, or CD123, similar to WT AML. More IDH1/2 (P = .015) and NPM1 (P = .002) mutations were seen in SRSF2-mutant AML than in SRSF2-mutant non-AML. Further, more IDH1/2, ASXL1, RUNX1, and STAG2 mutations were observed in SRSF2-mutant AML than in SRSF2-WT AML (P < .0001 to P = .001). Finally, patients with SRSF2-mutant AML showed a significantly worse overall survival (OS) than patients with SRSF2-WT AML (P < .0001), but this worse OS appeared to be rescued by allogeneic stem cell transplant (allo-SCT). CONCLUSIONS: Acute myeloid leukemia with altered SRSF2 shows a variable degree of morphologic dysplasia without uniform immunophenotypic aberrancies. SRSF2 mutations appear to be independent poor prognostic factors, but allo-SCT has improved the clinical outcomes in patients with SRSF2-mutant AML.

Application of a bioinformatic pipeline to RNA-seq data identifies novel virus-like sequence in human blood.

Numerous reports have suggested that infectious agents could play a role in neurodegenerative diseases, but specific etiological agents have not been convincingly demonstrated. To search for candidate agents in an unbiased fashion, we have developed a bioinformatic pipeline that identifies microbial sequences in mammalian RNA-seq data, including sequences with no significant nucleotide similarity hits in GenBank. Effectiveness of the pipeline was tested using publicly available RNA-seq data and in a reconstruction experiment using synthetic data. We then applied this pipeline to a novel RNA-seq dataset generated from a cohort of 120 samples from amyotrophic lateral sclerosis patients and controls, and identified sequences corresponding to known bacteria and viruses, as well as novel virus-like sequences. The presence of these novel virus-like sequences, which were identified in subsets of both patients and controls, were confirmed by quantitative RT-PCR. We believe this pipeline will be a useful tool for the identification of potential etiological agents in the many RNA-seq datasets currently being generated.

Saliva TwoStep for rapid detection of asymptomatic SARS-CoV-2 carriers.

Here, we develop a simple molecular test for SARS-CoV-2 in saliva based on reverse transcription loop-mediated isothermal amplification. The test has two steps: (1) heat saliva with a stabilization solution and (2) detect virus by incubating with a primer/enzyme mix. After incubation, saliva samples containing the SARS-CoV-2 genome turn bright yellow. Because this test is pH dependent, it can react falsely to some naturally acidic saliva samples. We report unique saliva stabilization protocols that rendered 295 healthy saliva samples compatible with the test, producing zero false positives. We also evaluated the test on 278 saliva samples from individuals who were infected with SARS-CoV-2 but had no symptoms at the time of saliva collection, and from 54 matched pairs of saliva and anterior nasal samples from infected individuals. The Saliva TwoStep test described herein identified infections with 94% sensitivity and >99% specificity in individuals with sub-clinical (asymptomatic or pre-symptomatic) infections.

High-resolution within-sewer SARS-CoV-2 surveillance facilitates informed intervention.

To assist in the COVID-19 public health guidance on a college campus, daily composite wastewater samples were withdrawn at 20 manhole locations across the University of Colorado Boulder campus. Low-cost autosamplers were fabricated in-house to enable an economical approach to this distributed study. These sample stations operated from August 25th until November 23rd during the fall 2020 semester, with 1512 samples collected. The concentration of SARS-CoV-2 in each sample was quantified through two comparative reverse transcription quantitative polymerase chain reactions (RT-qPCRs). These methods were distinct in the utilization of technical replicates and normalization to an endogenous control. (1) Higher temporal resolution compensates for supply chain or other constraints that prevent technical or biological replicates. (2) The data normalized by an endogenous control agreed with the raw concentration data, minimizing the utility of normalization. The raw wastewater concentration values reflected SARS-CoV-2 prevalence on campus as detected by clinical services. Overall, combining the low-cost composite sampler with a method that quantifies the SARS-CoV-2 signal within six hours enabled actionable and time-responsive data delivered to key stakeholders. With daily reporting of the findings, wastewater surveillance assisted in decision making during critical phases of the pandemic on campus, from detecting individual cases within populations ranging from 109 to 2048 individuals to monitoring the success of on-campus interventions.

Just 2% of SARS-CoV-2-positive individuals carry 90% of the virus circulating in communities.

We analyze data from the Fall 2020 pandemic response efforts at the University of Colorado Boulder (USA), where more than 72,500 saliva samples were tested for SARS-CoV-2 using quantitative RT-PCR. All samples were collected from individuals who reported no symptoms associated with COVID-19 on the day of collection. From these, 1,405 positive cases were identified. The distribution of viral loads within these asymptomatic individuals was indistinguishable from what has been previously reported in symptomatic individuals. Regardless of symptomatic status, approximately 50% of individuals who test positive for SARS-CoV-2 seem to be in non-infectious phases of the disease, based on having low viral loads in a range from which live virus has rarely been isolated. We find that, at any given time, just 2% of individuals carry 90% of the virions circulating within communities, serving as viral "super-carriers" and possibly also super-spreaders.

Saliva TwoStep for rapid detection of asymptomatic SARS-CoV-2 carriers.

Here, we develop a simple molecular test for SARS-CoV-2 in saliva based on reverse transcription loop-mediated isothermal amplification (RT-LAMP). The test has two steps: 1) heat saliva with a stabilization solution, and 2) detect virus by incubating with a primer/enzyme mix. After incubation, saliva samples containing the SARS-CoV-2 genome turn bright yellow. Because this test is pH dependent, it can react falsely to some naturally acidic saliva samples. We report unique saliva stabilization protocols that rendered 295 healthy saliva samples compatible with the test, producing zero false positives. We also evaluated the test on 278 saliva samples from individuals who were infected with SARS-CoV-2 but had no symptoms at the time of saliva collection, and from 54 matched pairs of saliva and anterior nasal samples from infected individuals. The Saliva TwoStep test described herein identified infections with 94% sensitivity and >99% specificity in individuals with sub-clinical (asymptomatic or pre-symptomatic) infections.

Transjugular intrahepatic portosystemic shunt for symptomatic refractory hepatic hydrothorax in patients with cirrhosis.

OBJECTIVES: We sought to study effectiveness, survival, and complications after transjugular intrahepatic portosystemic shunt (TIPS) in patients with cirrhosis and symptomatic refractory hepatic hydrothorax. METHODS: Consecutive patients who underwent TIPS between January 1992 and December 2008 for refractory hydrothorax were reviewed retrospectively. Clinical, laboratory, and procedural data were collected for all patients by retrospective chart review. Chi-square test was used to compare categorical variables and t-test to compare continuous variables. The Kaplan-Meier method was used for survival analysis. Survival curves were compared using the log-rank test. RESULTS: Seventy-three patients were included in the study, and their mean age at TIPS creation was 55.62 years (s.d. 11.65). The mean pre- and post-TIPS portosystemic gradients were 18.9 (s.d. 4.7) mm Hg and 5.7 (s.d. 2.4) mm Hg (P<0.001), respectively. The rates of favorable clinical response within 1 month and at 6 months after TIPS were 79% (58/73) and 75% (30/40), respectively. Median survival of the study group was 517 days (95% CI 11-626). The short-term survival rates at 30, 60, and 90 days were 81, 78, and 72%, respectively. The long-term survival rates at 1, 3, and 5 years were 48, 26, and 15%, respectively. Multivariate analysis by Cox proportional hazards method showed that pre-TIPS model for end-stage liver disease (MELD) score (P=0.039, HR 1.9 (95% CI 1.0-3.7)) and clinical response (P=0.003, HR 2.5 (95% CI 1.4-4.5)) were significantly and independently associated with overall survival. The 30-day mortality rate was 19%. Pre-TIPS creatinine levels (P=0.024, HR 3.42 (95% CI 1.2-9.9)) were significantly associated with 30-day mortality. CONCLUSIONS: TIPS can be successfully used to achieve symptomatic relief in patients with refractory hepatic hydrothorax. Better clinical response after TIPS and pre-TIPS MELD score less than 15 were associated with longer survival after TIPS.

De Novo Acute Myeloid Leukemia with Combined CBFB-MYH11 and BCR-ABL1 Gene Rearrangements: A Case Report and Review of Literature.

Acute myeloid leukemia (AML) with inv(16)(p13.1q22) resulting in CBFB-MYH11 fusion is associated with a favorable prognosis. The presence of a KIT mutation modifies it to an intermediate prognosis. Additionally, inv(16) can cooperate with other genetic aberrations to further increase cell proliferation. Coexistence of inv(16) and t(9;22) is extremely rare (20 cases). We present a case of a 55-year-old male with elevated white blood cell count. Bone marrow evaluation and flow cytometry analysis were compatible with AML with monocytic features. Cytogenetic studies revealed two-related clones, a minor clone with inv(16) and a major clone with concurrent inv(16) and t(9;22) rearrangements. Fluorescent in situ hybridization studies confirmed these rearrangements. Molecular analysis detected a p190 BCR-ABL1 transcript protein. KIT mutations were negative. The patient was initially treated with standard induction regimen; 7 daily doses of cytarabine from day 1-day 7, 3 daily doses of daunorubicin from day 1-day 3, and 1 dose of Mylotarg (gemtuzumab ozogamicin) on day 1. The detection of t(9;22) led to the addition of daily doses of dasatinib (tyrosine kinase inhibitor) from day 7 onwards. The patient achieved complete remission on day 45. During his treatment course, he acquired disseminated Fusarium infection. Day 180 bone marrow evaluation revealed florid relapse with 64% blasts. Cytogenetic study showed clonal evolution of the inv(16) clone with no evidence of the t(9;22) subclone. Eventually, bone marrow transplantation was contraindicated, and the patient was transferred to palliative care. Literature review revealed that AML with co-occurrence of CBFB-MYH11 and BCR-ABL1 gene rearrangements was involved by only a small number of cases with de novo and therapy-related AML. Most cases were in myeloid blast crisis of chronic myeloid leukemia (CML). Treatment and prognosis among the de novo AML cases varied and majority of them achieved clinical remission. In contrast, these cytogenetic abnormalities in the blast phase of CML had a poor prognosis. As the prognosis and management of AML is dependent upon the underlying genetic characteristics of the neoplasm, it is imperative to include clinical outcome with such rare combinations of genetic alterations.