We recently discovered that germline heterozygous mutations in the Replication Protein A1 (RPA1) gene cause Telomere Biology Disorder (TBD), a hereditary condition classically associated with pathological shortening of telomeres resulting in bone marrow failure (BMF), pulmonary and liver fibrosis, mucocutaneous fragility, and predisposition to solid tumors, myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) (10). This evidence concerns the gene RPA1 and Bone marrow hypocellularity.