Early-onset ataxia with ocular motor apraxia and hypoalbuminemia (EAOH) is a neurodegenerative disorder caused by mutation in the aprataxin (APTX)-coding gene APTX, which is involved in DNA single-strand break repair (SSBR). The neurological abnormalities associated with EAOH are similar to those observed in patients with ataxia-telangiectasia. However, the immunological abnormalities in patients with EAOH have not been described. In this study, we report that EAOH patients have immunological abnormalities, including lymphopenia; decreased levels of CD4⁺ T-cells, CD8⁺ T-cells, and B-cells; hypogammaglobulinemia; low T-cell recombination excision circles and kappa-deleting element recombination circles; and oligoclonality of T-cell receptor β-chain variable repertoire. These immunological abnormalities vary among the EAOH patients. Additionally, mild radiosensitivity in the lymphocytes obtained from the patients with EAOH was demonstrated. These findings suggested that the immunological abnormalities and mild radiosensitivity evident in patients with EAOH could be probably caused by the DNA repair defects.

早发性共济失调伴眼球运动性失用和低白蛋白血症 (EAOH) 是一种由 aprataxin (APTX) 编码基因APTX突变引起的神经退行性疾病，该基因参与 DNA 单链断裂修复 (SSBR)。与 EAOH 相关的神经系统异常与在共济失调-毛细血管扩张症患者中观察到的异常相似。然而，尚未描述 EAOH 患者的免疫学异常。在这项研究中，我们报告 EAOH 患者有免疫异常，包括淋巴细胞减少症；CD4 ⁺ T 细胞水平降低，CD8 ⁺T 细胞和 B 细胞；低丙种球蛋白血症; 低 T 细胞重组切除圈和 kappa 缺失元件重组圈；和 T 细胞受体 β 链可变库的寡克隆性。这些免疫异常在 EAOH 患者中有所不同。此外，还证实了从 EAOH 患者获得的淋巴细胞具有轻微的放射敏感性。这些发现表明EAOH患者明显的免疫异常和轻度放射敏感性可能是由DNA修复缺陷引起的。