Uchida Tomoyuki, Fujii Takayuki, Ohara Shin, Imai Yui, Inoue Morihiro, Harada Yuka, Harada Hironori, Hagihara Masao
Department of Hematology, Eiju General Hospital.
Clinical Research Support Center, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital.
Rinsho Ketsueki. 2022;63(8):865-869. doi: 10.11406/rinketsu.63.865.
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.
一名80岁的日本男性患者因疲劳症状前来我院就诊。他的外周血检查显示全血细胞减少，以淋巴细胞为主，无原始细胞。由于干抽，骨髓穿刺未成功，随后的骨髓活检显示骨髓细胞减少伴纤维化。根据CD34阳性细胞，他被诊断为伴有过多原始细胞（EB）-2的骨髓增生异常综合征（MDS）。骨髓染色体分析显示7号染色体单体，使用下一代测序检测到SAMD9 W22突变（变异等位基因频率[VAF]为51.22%）。在颊黏膜中观察到相同的突变（VAF为50%），经证实为种系突变。SAMD9基因突变被报道为MIRAGE综合征和儿童期MDS的致病基因之一。本病例被认为是由于SAMD9几乎全长缺失导致的功能丧失突变。这是首例以SAMD9 W22作为种系突变的成人MDS病例。
