•We describe “GATA2 deficiency related bone marrow and immunodeficiency disorder” (G2BMID).•G2BMID patients have hypocellular BM with no definitive dysplasia and with cytopenia.•G2BMID patients have ...clonal hematopoiesis with detectable MDS-associated mutations.
Germline mutation in GATA2 can lead to GATA2 deficiency characterized by a complex multi-system disorder that can present with many manifestations including variable cytopenias, bone marrow failure, myelodysplastic syndrome/acute myeloid leukemia (MDS/AML), and severe immunodeficiency. Penetrance and expressivity within families is often variable. There is a spectrum of bone marrow disease in symptomatic cytopenic patients ranging from hypocellular marrows without overt dysplasia to those with definitive MDS, AML, or chronic myelomonocytic leukemia. Relatives of probands with the same mutations may demonstrate minimal disease manifestations and normal marrows. A comprehensive clinical, hematological and genetic assessment of 25 patients with germline GATA2 mutation was performed. MDS-associated mutations were identified in symptomatic GATA2 patients both with overt MDS and in those with hypocellular/aplastic bone marrows without definitive dysplasia. Healthy relatives of probands harboring the same germline GATA2 mutations had essentially normal marrows that were overall devoid of MDS-associated mutations. The findings suggest that abnormal clonal hematopoiesis is a common event in symptomatic germline mutated GATA2 patients with MDS and also in those with hypocellular marrows without overt morphologic evidence of dysplasia, possibly indicating a pre-MDS stage warranting close monitoring for disease progression.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Fanconi anemia (FA) is predominantly an autosomal recessive inherited bone marrow failure syndrome (IBMFS) characterized by congenital anomalies, bone marrow failure (BMF) and an increased cancer ...risk. It is caused by pathogenic variants in more than 22 genes in the FA/BRCA DNA repair pathway. Approximately 60% of patients have biallelic variants in FANCA. We sought to identify phenotypic differences and clinical outcomes of patients with diverse FANCA variants.
We analyzed data from 86 patients with variants in FANCA enrolled in the National Cancer Institute (NCI) IBMFS study (ClinicalTrials.gov identifier 00027274). FANCA variants were determined through review of genetic test reports or whole exome sequencing done as part of the study. The variants were plotted using the online tool ProteinPaint (https://proteinpaint.stjude.org, Figure 1A). Clinical data were extracted from review of medical records and/or evaluations at the NIH.
We compared patients with: 1) hypomorphic (hypomorphic variant on one or both alleles) versus null genotype (null variants on both alleles), 2) single nucleotide variant (SNV)/small insertions/deletions (indels) on both alleles versus SNV/small indels on one allele plus large multi-exon deletion on the other allele versus large multi-exon deletions on both alleles. We further compared patients with one or biallelic variants involving the BRCA1 interaction region in the N-terminal domain, FAAP20-binding domain, and variants in exons 27 to 30 where we saw an accumulation of variants, with patients who did not have variants in these regions. We evaluated physical abnormalities that are part of VACTERL-H (Vertebral, Anal, Cardiac, Tracheo-esophageal fistula, Esophageal or duodenal atresia, Renal, upper Limb abnormalities, Hydrocephalus) association and PHENOS (skin Pigmentation abnormalities, small Head, small Eyes, central Nervous system, Otologic abnormalities, Short stature). We focused on the presence, severity and age at BMF, and development of cancers and age at first solid tumor. Frequencies were compared by Fisher's exact test, and a multiple Cox regression model was used to estimate hazard ratio of solid tumors in patients with variants in different regions of FANCA, adjusting for age and hematopoietic cell transplant status of patients with cancer. Analyses were performed using Excel and RStudio, p-value <0.05 was considered significant.
The phenotypes, BMF and cancer outcomes were similar between patients with hypomorphic and null genotypes. Similarly, comparison between patients with SNV/small indels, SNV/small indel plus large deletion, and biallelic large deletions did not reveal significant associations. Comparison according the location of the variants on FANCA protein showed that VACTERL-H and VACTERL-H plus PHENOS were less common in patients with at least one SNV/small indel in the BRCA1 interaction region of FANCA compared with patients without variants in this region (2/33 vs 12/51, p= 0.04; 1/33 vs 11/51, p= 0.024, respectively). These associations were not observed when we included patients with large deletions encompassing the BRCA1 interaction region.
Eighteen of the 86 patients developed solid tumors; 15/45 patients with an SNV/small indel and/or large deletion within or including exons 27-30 region developed solid tumors compared with 3/41 patients without variants in this region (p= 0.003). Cox regression analysis showed that patients with variants within or involving exons 27-30 were at higher risk of developing solid tumors compared with those without variants in this region (HR: 6.2, 95% CI: 1.36-28.2, Figure 1B). There was no difference between the age at first cancer or type of solid tumors in patients with and without the variant involving this region. The frequency, severity, and age of BMF were also similar between the groups.
Our data highlight the possibility that variants involving exons 27-30 within the C-terminal domain of FANCA may be associated with solid tumor development. FANCA forms a homodimer through the interaction between C-terminal domains; variants in this region may affect dimerization and further protein function. Functional analysis and in vivo studies of individual variants in this region and effects of the variants in trans might provide new insights into oncogenesis in FA and may have implications in personalized cancer screening.
Display omitted
No relevant conflicts of interest to declare.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Telomere biology disorders (TBDs) are caused by pathogenic germline variants in genes involved in telomere maintenance resulting in very short telomeres for age and high risks of bone marrow failure, ...certain cancers, as well as pulmonary and liver disease. Interestingly, some pathogenic TBD mutations have variable expressivity and incomplete penetrance, even within families. Variant carriers can present with early manifestations such as the mucocutaneous triad and bone marrow failure or may not manifest until later in life with adult-onset idiopathic pulmonary fibrosis or liver disease, or have no associated clinical phenotype. The underlying causes of this heterogeneity are poorly understood. We hypothesized that common genetic variants contributing to inter-individual variation in telomere length in the general population may combine with the effects of monogenic TBD-causing variants to underlie variable clinical manifestations in TBDs. To examine this, we developed polygenic scores (PGS) to predict telomere length using genome-wide SNPs from the UK Biobank. We then applied the most predictive polygenic score to the out-of-sample All of Us cohort, as well as the National Cancer Institute's longitudinal cohort of individuals with inherited bone marrow failure syndromes, including those with TBDs (ClinicalTrials.gov Identifier: NCT00027274). If monogenic mutations and polygenic predisposition to short telomeres both contribute to the clinical severity of TBDs and likelihood of early-onset manifestations, the distribution of genetically predicted telomere length in this ascertained cohort would be shifted towards shorter telomeres compared with the population average. Consistent with this, individuals with TBDs enriched for early-onset bone marrow failure phenotypes (n = 92) have a median polygenic score 0.32 standard deviations (SDs) shorter than the UK Biobank (p=0.002), and 0.31 SDs shorter than the external All of Us cohort (p=0.003) ( Figure). Individuals with TBDs also have shorter genetically predicted telomeres compared to individuals with Fanconi anemia (n = 45) and Diamond Blackfan anemia (n = 49) (p=0.008), indicating that this phenomenon is specific to TBDs. We binned the PGS into quintiles and show that the lowest quintile is associated with an odds ratio of TBD of 1.89 1.19,2.86, while being in the highest quintile is associated with an odds ratio of 0.54 0.29,1.02. Interestingly, TBD cases with no identified mutation have a median PGS 0.1 SDs towards shorter telomeres than patients with a known mutation. Collectively, these results indicate that common, genome-wide determinants of telomere length are significant modifiers of the early-onset manifestations of TBDs. We hypothesized that the converse should also be true: TBD causal variants should be present in adult population cohorts, and adult individuals with a pathogenic variant who avoided the severe childhood-onset manifestations of TBDs, should not have polygenically predicted short telomere length. To test this hypothesis, we filtered the UK Biobank for TBD causal variants annotated in ClinVar, and identified 71 putative pathogenic cases. Importantly, among these cases there were no individuals with bone marrow failure, but these individuals did have shorter telomeres compared with the UK Biobank. Interestingly, these 71 putative cases had a population-normal telomere length PGS, and significantly longer PGS predicted telomere length than the NCI cohort (p=0.025). We also find that being classified as among these pathogenic cases is associated with an odds ratio for developing pulmonary fibrosis of 10.79 4.34,26.8. In summary, despite normal PGS and absence of bone marrow failure, these putative cases have short telomeres and increased risk of adult manifestations of TBDs, consistent with the idea that the pathogenic mutations and common genetic variation affecting telomere length combine to impact expressivity. Collectively, these findings indicate that polygenic effects on telomere length can modify the impacts of monogenic mutations in TBD-associated genes. These results have implications not only for clinical risk assessment in patients with TBDs, but also for our general understanding and interpretation of variable penetrance/expressivity in presumed monogenic disorders.
Full text
Available for:
NUK, OILJ, SAZU, SBCE, UL, UM, UPCLJ, UPUK
▪
Fanconi anemia (FA) is a predominantly autosomal recessive disorder resulting from mutations in one of >22 genes involved in the FA/BRCA DNA repair pathway. FA is characterized by multiple ...congenital abnormalities, progressive bone marrow failure (BMF) and cancer predisposition. Genetic heterogeneity and diverse clinical presentations challenge early diagnosis and optimal management. We previously reviewed the genotype-phenotype associations in FA from literature cases (Fiesco-Roa MO et al. Blood Rev. 2019). We now report the results from the NCI cohort.
We studied 147 patients with FA in the NCI inherited bone marrow failure syndromes Cohort Study (ClinicalTrials.gov, NCT00027274) to explore genotype phenotype associations by genes, location in the FA/BRCA pathway (upstream, ID complex, downstream), and compare information on the clinic cohort (CC) and field cohort (FC) patients. 57 patients (CC) were evaluated at the NIH Clinical Center between 2002 and 2020. Details on 90 patients in the FC were obtained from the review of medical records. The sex ratio (M:F) was similar (0.6:1 and 0.8:1). Patients in the FC were younger than in the CC (p=0.004) with median ages 27 (3-68) years for the CC and 19 (0-57) for the FC.
The main genotypes in the CC were 59% FANCA, 17% FANCC, 6% FANCI and in the FC were 60% FANCA, 13% FANCC and 8% FANCG. At least one FA type physical abnormality was present in all CC patients and 73/79 (92%) FC patients (phenotype data not reported on 11 FC patients). >3/8 VACTERL-H features (Vertebral, Anal, Cardiac, Tracheo-esophageal fistula (TEF), Esophageal or duodenal atresia, Renal, upper Limb (radial ray) and Hydrocephalus) were present in 32% of CC patients and 16% of FC (p=0.04). At least 4/6 PHENOS features (skin Pigmentation, small Head, small Eyes, other central Nervous system (CNS) anomalies, Otology and Short stature) were present in 54% of CC patients and 34% FC (p=0.02). The types and frequencies of phenotypic abnormalities are shown in figure 1. 17 patients in the CC (30%) and 10 in the FC (13%) had both VACTERL-H and PHENOS (p=0.01). We excluded patients with unknown genotype or phenotype from further analysis. In the CC, cardiac abnormalities were more common in patients with FANCI or ID complex gene variants than in all others (p=0.02 and 0.001, respectively) as were VACTERL-H and structural CNS abnormalities in patients with ID complex variants (p=0.03 and 0.006, respectively). In the FC, VACTERL-H, imperforate anus and hydrocephalus were more common in patients with FANCD1 genotype (p=0.03, 0.009 and 0.004, respectively) and downstream pathway gene variants (p=0.004, <0.001 and 0.03, respectively). PHENOS, renal and neurodevelopmental abnormalities were less common in patients with upstream genes variants (p=0.001, 0.009 and <0.001, respectively). Upper limb abnormalities were less common in patients with FANCC genotype (p=0.007).
BMF was present in 121/147 (88%) patients; 33% had been transfusion-dependent and 26% received androgen therapy. Clonal cytogenetic abnormalities were seen in 30%; 17% developed myelodysplastic syndrome at a median age of 17 (1.4-44) years and 6 patients developed acute myeloid leukemia at a median age of 19 (12-29) years. 72 (49%) patients underwent bone marrow transplant at a median age of 9.5 (1.5-44) years for BMF, MDS or leukemia. There was no significant difference between the FC and CC. The median survival age of our cohort is 38 (95% CI 34-43) years and at least 80% of our patients are >18 years of age. Kaplan-Meier survival estimates are presented in figure 2. Solid tumors developed in 30/135 (22%) patients with available data; median age at first cancer was 30 (2-44) years. The most common tumor was head and neck squamous cell carcinoma (n=15 patients), followed by skin (n=8) and anogenital cancers (n=6); many patients developed multiple cancers. Detailed hematologic, cancer, endocrine outcomes and survival analyses are ongoing.
Overall, renal and upper limb abnormalities were reported in most of the patients in both CC and FC, as shown previously (Alter BP et al. Mol Syndromol. 2013). Data from the CC were more complete than from the review of charts from the FC highlighting that the clinical in person evaluation of patients provides detailed characterization of FA phenotypes and more accurate assessment of genotype-phenotype associations. This will facilitate timely diagnosis, surveillance and clinical management of patients with FA.
Display omitted
No relevant conflicts of interest to declare.
Full text
Available for:
NUK, OILJ, SAZU, SBCE, UL, UM, UPCLJ, UPUK
Background
Fanconi anemia (FA) is an inherited bone marrow failure syndrome associated with characteristic dysmorphology primarily caused by biallelic pathogenic germline variants in any of 22 ...different DNA repair genes. There are limited data on the specific molecular causes of FA in different ethnic groups.
Methods
We performed exome sequencing and copy number variant analyses on 19 patients with FA from 17 families undergoing hematopoietic cell transplantation evaluation in Pakistan. The scientific literature was reviewed, and we curated germline variants reported in patients with FA from South Asia and the Middle East.
Results
The genetic causes of FA were identified in 14 of the 17 families: seven FANCA, two FANCC, one FANCF, two FANCG, and two FANCL. Homozygous and compound heterozygous variants were present in 12 and two families, respectively. Nine families carried variants previously reported as pathogenic, including two families with the South Asian FANCL founder variant. We also identified five novel likely deleterious variants in FANCA, FANCF, and FANCG in affected patients.
Conclusions
Our study supports the importance of determining the genomic landscape of FA in diverse populations, in order to improve understanding of FA etiology and assist in the counseling of families.
Fanconi anemia (FA) primarily caused by biallelic pathogenic germline variants in any of 22 different DNA repair genes but there are limited data on the specific FA gene variants in cases from the Middle East and South Asia. We identified novel and known genetic causes of FA in 14 of 17 families from Pakistan. Our study supports the importance of determining the genomic landscape of FA in diverse populations, in order to improve understanding of FA etiology and assist in the counseling of families.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Prior research has established that the prevalence of pathogenic/likely pathogenic (P/LP) variants across all of the American College of Medical Genetics (ACMG) Secondary Findings (SF) genes is ...approximately 0.8-5%. We investigated the prevalence of P/LP variants in the 24 ACMG SF v2.0 cancer genes in a family-based cancer research cohort (n = 1173) and in cancer-free ethnicity-matched controls (n = 982).
We used InterVar to classify variants and subsequently conducted a manual review to further examine variants of unknown significance (VUS).
In the 24 genes on the ACMG SF v2.0 list associated with a cancer phenotype, we observed 8 P/LP unique variants (8 individuals; 0.8%) in controls and 11 P/LP unique variants (14 individuals; 1.2%) in cases, a non-significant difference. We reviewed 115 VUS. The median estimated per-variant review time required was 30 min; the first variant within a gene took significantly (p = 0.0009) longer to review (median = 60 min) compared with subsequent variants (median = 30 min). The concordance rate was 83.3% for the variants examined by two reviewers.
The 115 VUS required database and literature review, a time- and labor-intensive process hampered by the difficulty in interpreting conflicting P/LP determinations. By rigorously investigating the 24 ACMG SF v2.0 cancer genes, our work establishes a benchmark P/LP variant prevalence rate in a familial cancer cohort and controls.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The zebrafish is an established animal model system that profits from the availability of strong experimental approaches in both genetics and embryology. As a vertebrate, zebrafish can be used to ...model many aspects of human development and disease. GATA transcription factors play important roles in the development of many organ systems, including those for hematopoietic, cardiovascular, reproductive, and gut-endoderm derived tissues. The six vertebrate GATA factors are highly conserved in zebrafish at the level of sequence, expression pattern, and function. The identification of mutants, establishment of transgenic GFP reporter fish, and the ease of performing loss- and gain-of-function experiments have all contributed new insight into our understanding of the regulation and function of GATA factors. We review recent advances toward this goal using the zebrafish system with a focus on hematopoiesis and cardiogenesis, and suggest how comparative genetics using the zebrafish genes might reveal core conserved properties, as well as changes in gene function that reflect different morphogenetic programs utilized by various vertebrate embryos.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
10589
Background: Fanconi anemia (FA) is a cancer predisposition syndrome caused by biallelic pathogenic variants in one of 22 genes involved in DNA intrastrand crosslink repair. 20 of these genes ...have an autosomal recessive inheritance pattern. Of the FA genes, 5 ( BRCA1, BRCA2, BRIP1, PALB2, RAD51C) are known cancer predisposition genes (CPG) when inherited in monoallelic autosomal dominant manner, though the heterozygous predisposition status of the remaining 15 remains unclear. Large population-level exome sequencing projects with linked health records such as the DiscovEHR cohort serve as promising tools to establish sufficient power to investigate all FA genes. Quantifying cancer risk is important for the counseling and surveillance of FA heterozygotes, especially with the ever-increasing use of genetic testing identifying these individuals. Methods: 170,503 individuals enrolled in the DiscovEHR Cohort were analyzed for pathogenic/likely pathogenic variants in 22 FA genes and identified 5834 subjects, the case group. ICD10 phenotype classifications for these subjects were curated to Phecodes and ICD-O-3 Site Recodes for two control arms of analysis. The first control arm included all DiscovEHR subjects excluding the case group and those with a variant of uncertain significance in the genes of interest with a deleterious in-silico score. The second control arm included individuals from the Surveillance, Epidemiology, and End Results (SEER) database. Phecode analysis yielded odds ratios adjusted for age, sex, race, smoking status, and BMI. SEER analysis yielded Standardized Incidence Ratio scores adjusted for age, sex, and birth cohort. When both arms of the analysis were completed Phecodes and SEER analyses were matched and positive signals for cancer risk were defined by statistically significant ratios in both. Results: The 5 known CPGs demonstrated multiple signals for cancer predisposition as expected (p < 0.0001). Results for FANCA (p = 0.4231) and FANCC (p = 0.8142) heterozygotes validated recent results from our group showing no increased risk of cancer in relatives of FA patients with these genotypes. Ten other FA genes also showed no increased risk of cancer. 3 genes suggested a possible increased risk of specific cancers in heterozygotes and are currently being evaluated in a second large population exome cohort to validate these findings. Conclusions: This is the largest study to date on the cancer predisposition risk in Fanconi anemia heterozygotes. We have confirmed the known risk in 5 well-described CPGs and the lack of risk amongst FANCA and FANCC heterozygotes, the most common in population. Further analysis via an additional large population cohort is underway to validate any possible novel cancer predispositions in 3 genes. For the remaining FA genes, this population analysis supports previous literature on known CPGs and the lack of cancer predisposition in most FA genes.
The bone morphogenetic protein (BMP) signaling pathway regulates multiple steps of hematopoiesis, mediated through receptor-regulated Smads, including Smad1 and Smad5. Here, we use loss-of-function ...approaches in zebrafish to compare the roles of Smad1 and Smad5 during embryonic hematopoiesis. We show that knockdown of Smad1 or Smad5 generates distinct and even opposite hematopoietic phenotypes. Embryos depleted for Smad1 have an increased number of primitive erythrocytes, but fail to produce mature embryonic macrophages. In contrast, Smad5-depleted embryos are defective in primitive erythropoiesis, yet have normal numbers of macrophages. Loss of either Smad1 or Smad5 causes a failure in the generation of definitive hematopoietic progenitors. To investigate the mechanism behind these phenotypes, we used rescue experiments and found that Smad5 is unable to rescue the Smad1 loss-of-function phenotype, indicating that the 2 highly related proteins have inherently distinct activities. Microarray experiments revealed that the 2 proteins redundantly regulate the key initiators of the hemato-vascular program, including scl, lmo2, and gfi1. However, each also regulates a remarkably distinct genetic program, with Smad5 uniquely regulating the BMP signaling pathway itself. Our results suggest that specificity of BMP signaling output, with respect to hematopoiesis, can be explained by differential functions of Smad1 and Smad5.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
GATA2 deficiency syndrome is caused by autosomal dominant, heterozygous germline mutations with widespread effects on immune, pulmonary and vascular systems. Patients commonly develop hematological ...abnormalities including bone marrow failure, myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). We present a patient with GATA2 mutation and MDS who progressed to AML over four months. Whole exome and targeted deep sequencing identified a new p.Q61K NRAS mutation in the bone marrow at the time of AML development. Rapid development of AML is possible in the setting of germline GATA2 mutation despite stable MDS, supporting close monitoring and consideration of early allogeneic transplantation.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
