Genetic and Clinical Spectrum of SAMD9 and SAMD9L Syndromes: from Variant Interpretation to Patient Management

SAMD9 and SAMD9L (SAMD9/9L) are paralogous genes encoding antiviral proteins that negatively regulate cell proliferation. Heterozygous germline gain-of-function (GoF) SAMD9/9L variants cause multisystem syndromes with variable manifestations. The unifying features are cytopenia, immunodeficiency, infections, bone marrow failure (BMF), myelodysplasia (MDS) and monosomy 7. Non-hematopoietic presentations can affect almost every organ system. Growth impairment and adrenal insufficiency are …