Clinical and translational studies of RUNX1 and FPDMM

RUNX1基因的胚系突变导致家族性血小板紊乱伴相关髓系恶性肿瘤(FPDMM)，这是一种罕见的常染色体显性遗传病。这种疾病的患者具有巨核细胞发育缺陷、血小板计数低和导致凝血缺陷的血小板功能缺陷，以及血液系统恶性肿瘤的易感性。FPDMM患者一生都有患恶性血液病的风险，在具有不同RUNX1胚系突变的家庭中，甚至在具有相同RUNX1突变的单个家庭中受影响的个人之间，临床表现和疾病外显性不同。目前还没有良好的生物标志物或简单的检测方法来预测疾病的结果，患者需要频繁的办公室访问和侵入性程序，如骨髓活检来监测他们的疾病进展。许多FPD患者不会发生白血病的事实表明，RUNX1突变本身不足以导致白血病；还需要更多的体细胞突变和克隆进化。 为了解决这些问题，以更好地了解FPDMM的临床病程和潜在的致病机制，我们于2019年初在NIH临床中心启动了FPDMM的自然历史研究。 Https://clinicaltrials.gov/ct2/show/NCT03854318 Https://clinicalstudies.info.nih.gov/ProtocolDetails.aspx?A_19-HG-0059.html%20InternalRUNX1 自然病史研究的目标是识别和跟踪FPDMM患者，希望识别可以预测哪些患者将进展和发展为恶性肿瘤的生物标记物，并识别可能影响临床表现、疾病严重程度和向恶性肿瘤进展的继发性基因突变。通过我们的研究，我们希望确定RUNX1突变的基因型-表型相关性，并验证与RUNX1胚系突变协同的第二次命中对白血病发生的重要性。我们希望对患者进行全面的表型分析，以确定胚系RUNX1突变的全谱表现。 从2021年7月到2022年7月，我们招募了101名自然历史研究参与者。我们有55名参与者在同一时期访问了NIH临床中心(CC)进行年度体检。此外，我们还与不能前往NIH的患者进行了远程保健会议，并从在当地进行手术的患者那里收到了远程患者的样本(血液和骨髓)。对于到NIH CC就诊的患者，我们进行了临床检查和实验室测试，以记录与FPDMM相关的临床表现，包括那些造血系统以外的患者。我们采集了外周血和骨髓样本进行血液学、免疫学和组织学检查和测试。通过在NIH CC收集和远程接收的生物样本，我们一直在进行基因组分析，以确定参与者的造血细胞的种系和体细胞变化。我们还在进行功能和翻译研究，以确定在我们的患者中检测到的RUNX1变体的功能后果，使用的既有台式研究工具，也有模型系统，包括来自患者样本的细胞系和动物模型，如斑马鱼和小鼠。我们的数据将很快提供给研究界，既可以作为同行评议期刊上发表的研究论文，也可以作为研究界可访问的已确定身份的数据库。

Germline mutations in RUNX1 cause familial platelet disorder with associated myeloid malignancies (FPDMM), a rare autosomal dominant disease. Patients with this disorder have defective megakaryocytic development, low platelet count and defective platelet functions that lead to clotting defects, and predisposition of the patients for hematological malignancies. FPDMM patients have a life-long risk of hematopoietic malignancies, with variable clinical presentation and disease penetrance among families with different RUNX1 germline mutations, and even between affected individuals within a single family who have the same RUNX1 mutation. Currently there are no good biomarkers or easy assays to predict disease outcome, and the patients need to have frequent office visits and invasive procedures such as bone marrow biopsy to monitor their disease progression. The fact that many FPD patients do not develop leukemia suggest that RUNX1 mutation by itself is not sufficient for leukemogenesis; additional somatic mutations followed by clonal evolution are needed. To address these issues for better understanding of the clinical course and underlying pathogenic mechanism of FPDMM, we launched a natural history study of FPDMM at the NIH Clinical Center in early 2019. https://clinicaltrials.gov/ct2/show/NCT03854318 https://clinicalstudies.info.nih.gov/ProtocolDetails.aspx?A_19-HG-0059.html%20InternalRUNX1 The goals of the natural history study are to identify and follow patients with FPDMM with the hope of identifying biomarkers that can predict which patients will progress and develop malignancies and to identify secondary gene mutations that may impact clinical presentation, disease severity, and progression to malignancies. Through our study we hope to determine genotype-phenotype correlations for RUNX1 mutations and validate the importance of 2nd hits that cooperate with RUNX1 germline mutations for leukemogenesis. And we desire to comprehensively phenotype the patients to determine the full spectrum of the manifestations of the germline RUNX1 mutations. From July 2021 to July 2022, we enrolled 101 participants in our natural history study. We had 55 participants who visited NIH Clinical Center (CC) for their annual checkups during the same period. In addition, we have performed telehealth sessions with patients who could not travel to NIH and received remote patient samples (blood and bone marrow) from patients who had procedures locally. For patients who visited NIH CC, we performed clinical examinations and lab tests to document clinical manifestations associated with FPDMM, including those outside of the hematopoietic system. We collected peripheral blood and bone marrow samples for hematological, immunological, and histological examinations and tests. With the biological samples, both collected at NIH CC and received remotely, we have been performing genomic analysis to determine germline and somatic changes in the hematopoietic cells in the participants. We are also performing functional and translational studies to determine the functional consequences of the detected RUNX1 variants in our patients, with both bench research tools as well as model systems including cell lines derived from patient samples and animal models such as the zebrafish and mouse. Our data will be made available to the research community soon, both as research articles published in peer-reviewed journals and as deidentified databases accessible to the research community.