Abstract：
An 80-year-old Japanese male patient presented to our hospital with complaints of fatigue. His peripheral blood tests revealed pancytopenia with predominant lymphocytes and without blasts. The bone marrow (BM) aspiration was unsuccessful due to a dry tap, and the subsequent BM biopsy revealed hypocellular marrow with fibrosis. He was diagnosed with myelodysplastic syndrome (MDS) with excess blasts (EB)-2 based on CD34-positive cells. The chromosome analysis of the BM revealed monosomy 7, and the SAMD9 W22* mutation was detected (variant allele frequency [VAF] of 51.22%) using next-generation sequencing. An identical mutation was observed in the buccal mucosa (VAF of 50%), which was confirmed as a germline mutation. The SAMD9 gene mutation is reported as one of the causative genes for MIRAGE syndrome and child-onset MDS. The present case was considered a loss-of-function mutation due to the near full-length SAMD9 deletion. This is the first adult case of MDS with SAMD9 W22* as a germline mutation.
摘要：
一位80岁的日本男性患者因疲劳而来到我们医院。他的外周血检查显示全血细胞减少症，淋巴细胞占优势，没有母细胞。由于干燥的水龙头，骨髓（BM）抽吸失败，随后的BM活检显示骨髓细胞减少伴纤维化。基于CD34阳性细胞，他被诊断为骨髓增生异常综合征（MDS），并带有过量的母细胞（EB）-2。BM的染色体分析显示为单体7，并且使用下一代测序检测到SAMD9W22*突变（变异等位基因频率[VAF]为51.22％）。在颊粘膜中观察到相同的突变（VAF为50％），这被证实是种系突变。据报道，SAMD9基因突变是MIRAGE综合征和儿童期MDS的致病基因之一。由于接近全长SAMD9缺失,本病例被认为是功能丧失突变。这是第一个以SAMD9W22*为种系突变的MDS成人病例。
