A clinical case of myelodysplastic syndrome with monosomy 7 in a patient with a mutation in the SAMD9L gene

Abstract

Conditions associated with defects in the SAMD9 and SAMD9L genes are a group of nosologies with a range of clinical symptoms from multisystem lesions in the framework of MIRAGE syndrome to isolated hematological manifestations. The article presents a clinical case of a patient with myelodysplastic syndrome and a germline mutation in the SAMD9L gene. Patient V. developed first symptoms of her illness at the age of 1 year 1 month. She was hospitalized with complaints of a hemorrhagic rash and fever; the hemogram showed isolated thrombocytopenia. A diagnosis of immune thrombocytopenia was established. Given the lack of effect from the first-line therapy, the diagnosis was revised to aplastic anemia. Spontaneous restoration of hematopoiesis was observed 8 days later. At the age of 1 year 5 months, thrombocytopenia and neutropenia were observed. At the age of 2 years, she was initially hospitalized at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology and was diagnosed with myelodysplastic syndrome, monosomy 7. The only curative treatment for the disease is allogeneic hematopoietic stem cell transplantation (HSCT). Based on the results of wholegenome sequencing, a germline de novo missense mutation in the SAMD9L gene (“gain-of-function”) was detected. At 2 years and 10 months, the patient was readmitted to the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. Transformation into acute leukemia was ruled out, and allogeneic HSCT was performed from a related haploidentical donor. A follow-up examination within the 30th day showed that the graft was functioning satisfactorily, with blasts less than 5% in the myelogram and no signs of dyspoiesis. Conditions associated with mutations in the SAMD9 / SAMD9L genes are rare. Timely diagnosis and prompt HSCT can improve survival rates and reduce the risk of long-term complications.