Autoimmune polyendocrine syndrome type-1 (APS1) is characterized by autoimmune manifestations affecting different organs from early childhood on. Immunological abnormalities, the resulting endocrinopathies, and their treatments may compromise bone health. For the first time in APS1, we analyzed transiliac bone biopsy samples by bone histomorphometry and quantitative backscattered electron imaging in three adult patients (female P1, 38 years; male P2, 47 years; male P3, 25 years). All had biallelic mutations in the autoimmune regulator gene and in addition to endocrinopathies, also significant bone fragility. Histomorphometry showed bone volume in the lower normal range for P1 (BV/TV, − 0.98 SD) and P3 (− 1.34 SD), mainly due to reduced trabecular thickness (TbTh, − 3.63 and − 2.87 SD). In P1, osteoid surface was low (OS/BS, − 0.96 SD); active osteoblasts and double labeling were seen only on cortical bone. P3 showed a largely increased bone turnover rate (BFR/BV, + 4.53 SD) and increased mineralization lag time (Mlt, + 3.40 SD). Increased osteoid surface (OS/BS, + 2.03 and + 4.71 SD for P2 and P3) together with a large proportion of lowly mineralized bone area (Trab CaLow, + 2.22 and + 9.81 SD for P2 and P3) and focal mineralization defects were consistent with abnormal mineralization. In all patients, the density and area of osteocyte lacunae in cortical and trabecular bone were similar to healthy adults. The bone tissue characteristics were variable and included decreased trabecular thickness, increased amount of osteoid, and abnormal mineralization which are likely to contribute to bone fragility in patients with APS1.

自身免疫性多内分泌综合征 1 型 (APS1) 的特点是自幼儿期起就影响不同器官的自身免疫表现。免疫异常、由此产生的内分泌疾病及其治疗可能会损害骨骼健康。我们首次在 APS1 中通过骨组织形态计量学和定量背散射电子成像分析了三名成年患者（女性 P1，38 岁；男性 P2，47 岁；男性 P3，25 岁​​）的经髂骨活检样本。所有患者的自身免疫调节基因均存在双等位基因突变，除了内分泌疾病外，还有显着的骨质脆性。组织形态计量学显示 P1（BV/TV，− 0.98 SD）和 P3（− 1.34 SD）的骨体积处于正常范围下限，主要是由于小梁厚度减少（TbTh，− 3.63 和 − 2.87 SD）。在 P1 中，类骨表面较低（OS/BS，- 0. 96 标准差）；仅在皮质骨上观察到活性成骨细胞和双重标记。P3 显示骨转换率大幅增加（BFR/BV，+ 4.53 SD）和矿化滞后时间增加（Mlt，+ 3.40 SD）。类骨质表面增加（OS/BS，P2 和 P3 为 + 2.03 和 + 4.71 SD），以及大部分低矿化骨区域（Trab CaLow，P2 和 P3 为 + 2.22 和 + 9.81 SD），局灶性矿化缺陷是一致的伴有矿化异常。在所有患者中，皮质骨和骨小梁中骨细胞陷窝的密度和面积与健康成人相似。骨组织特征各不相同，包括小梁厚度减少、骨样数量增加以及矿化异常，这些可能导致 APS1 患者骨脆性。