Project description:Transcriptome profile of highly purified multipotential (P), erythroid (E), and myeloid (M) bone marrow progenitors from three RPS19 mutated Diamond-Blackfan anemia and six control human subjects. Two group comparison of sex and age matched subjects. Bone marrow progenitors, gene expression profiling, Diamond-Blackfan anemia, RPS19
Project description:Diamond-Blackfan anemia (DBA) is a rare bone marrow failure disorder that affects 7 out of 1,000,000 live births and has been associated with mutations in components of the ribosome. In order to characterize the genetic landscape of this heterogeneous disorder, we recruited a cohort of 472 individuals with a clinical diagnosis of DBA and performed whole exome sequencing (WES). We identified rare and predicted damaging mutations in likely causal genes for 78% of individuals. The majority of mutations were singletons, absent from population databases, predicted to cause loss of function, and in one of 19 previously reported ribosomal protein (RP) encoding genes. Using exon coverage estimates, we identified and validated 31 deletions in RP genes. We also observed an enrichment for extended splice site mutations and validated their diverse effects using RNA sequencing in individual-derived cell lines. Leveraging the size of our cohort, we observed robust genotype-phenotype associations with congenital abnormalities and treatment outcomes. We further identified rare mutations in 7 previously unreported RP genes that may cause DBA, as well as several distinct disorders that appear to phenocopy DBA, including 9 individuals with biallelic CECR1 mutations that result in deficiency of ADA2. However, no new genes were identified at exome-wide significance, suggesting that there are no unidentified genes containing mutations readily identified by WES that explain > 5% of DBA cases. Overall, this report should not only inform clinical practice for DBA individuals, but also the design and analysis of rare variant studies for heterogeneous Mendelian disorders.
Project description:Gene expression analysis from erythroid progenitors (CD34+/CD71(high)/CD45- mononuclear cells from the bone marrow) of patients with Diamond-Blackfan anemia (due to RPS19 mutations) and control individuals.
Project description:We found that endogenously expressed RPS19 binds evolutionarily constrained intronic elements. By assessing overexpression of WT RPS19 and RPS19 harboring the most common Diamond-Blackfan anemia missense mutations, we confirmed that disease-relevant mutations alter RPS19 binding preferences in human cells.
Project description:RPS19 mutations are the most common cause of the human disorder Diamond Blackfan Anemia. The R62W mutation was hypothesized to act in a dominant negative fashion and mice expressing RPS19R62W have many of the characteristics of Diamond Blackfan Anemia. Diamond-Blackfan Anemia (DBA), is an inherited erythroblastopenia associated with mutations in at least 8 different ribosomal protein genes. Mutations in the gene encoding Ribosomal Protein S19 (RPS19) have been identified in ~25% of DBA families. Most of these mutations disrupt either the translation or stability of the RPS19 protein and are predicted to cause DBA by haploinsufficiency. However, approximately ~30% of RPS19 mutations are missense mutations that do not alter the stability of the RPS19 protein and are hypothesized to act by a dominant negative mechanism. To formally test this hypothesis, we generated a transgenic mouse model expressing an RPS19 mutation in which an Arginine residue is replaced with a Tryptophan residue at codon 62 (RPS19R62W). Constitutive expression of RPS19R62W in developing mice was lethal. Conditional expression of RPS19R62W resulted in growth retardation, a mild anemia with reduced numbers of erythroid progenitors and significant inhibition of terminal erythroid maturation, similar to DBA. RNA profiling demonstrated over 700 dysregulated genes belonging to the same pathways that are disrupted in RNA profiles of DBA patient cells.
Project description:Transcriptome profile of highly purified multipotential (P), erythroid (E), and myeloid (M) bone marrow progenitors from three RPS19 mutated Diamond-Blackfan anemia and six control human subjects.
Project description:RPS19 mutations are the most common cause of the human disorder Diamond Blackfan Anemia. The R62W mutation was hypothesized to act in a dominant negative fashion and mice expressing RPS19R62W have many of the characteristics of Diamond Blackfan Anemia. Diamond-Blackfan Anemia (DBA), is an inherited erythroblastopenia associated with mutations in at least 8 different ribosomal protein genes. Mutations in the gene encoding Ribosomal Protein S19 (RPS19) have been identified in ~25% of DBA families. Most of these mutations disrupt either the translation or stability of the RPS19 protein and are predicted to cause DBA by haploinsufficiency. However, approximately ~30% of RPS19 mutations are missense mutations that do not alter the stability of the RPS19 protein and are hypothesized to act by a dominant negative mechanism. To formally test this hypothesis, we generated a transgenic mouse model expressing an RPS19 mutation in which an Arginine residue is replaced with a Tryptophan residue at codon 62 (RPS19R62W). Constitutive expression of RPS19R62W in developing mice was lethal. Conditional expression of RPS19R62W resulted in growth retardation, a mild anemia with reduced numbers of erythroid progenitors and significant inhibition of terminal erythroid maturation, similar to DBA. RNA profiling demonstrated over 700 dysregulated genes belonging to the same pathways that are disrupted in RNA profiles of DBA patient cells. The samples compared are RNA extracted from CD71 positive erythroblasts sorted from the bone marrow of wild type mice and mice expressing a mutant RPS19 (RPS19R62W) transgene
Project description:Gene expression analysis from erythroid progenitors (CD34+/CD71(high)/CD45- mononuclear cells from the bone marrow) of patients with Diamond-Blackfan anemia (due to RPS19 mutations) and control individuals. Case-control microarray gene expression analysis
Project description:Diamond Blackfan anemia is a congenital bone marrow failure syndrome characterized by hypoproliferative anemia, often with associated physical abnormalities. Perturbations of the ribosome appear critically important to the development of DBA, as alterations in 9 different ribosomal protein genes have been identified in multiple unrelated families, along with rarer abnormalities of additional ribosomal proteins. However, presently only 50-60% of patients have an identifiable genetic lesion by ribosomal protein gene sequencing. Using genome-wide SNP array to evaluate for regions of recurrent copy variation, we identified 2 patients with mosaic loss in the region of the the chromosome 5-deleted region involved in somatically-acquired 5q- myelodysplastic syndrome.
Project description:Diamond Blackfan anemia is a congenital bone marrow failure syndrome characterized by hypoproliferative anemia, often with associated physical abnormalities. Perturbations of the ribosome appear critically important to the development of DBA, as alterations in 9 different ribosomal protein genes have been identified in multiple unrelated families, along with rarer abnormalities of additional ribosomal proteins. However, presently only 50-60% of patients have an identifiable genetic lesion by ribosomal protein gene sequencing. Using genome-wide SNP array to evaluate for regions of recurrent copy variation, we identified deletions at known DBA-related ribosomal protein gene loci in 17% (9/51) of patients without an identifiable mutation, including RPS19, RPS17, RPS26, and RPL35A