背景:神经母细胞瘤扩增序列(NBAS)相关疾病是一种常染色体隐性遗传疾病,已报道了广泛的临床症状。然而,自身免疫介导的溶血性贫血(AIHA)在NBAS疾病中很少报道。
方法:现在21岁的男性港口杂合变异c.6840G>A和c.335+1G>A,被发现生长迟缓,低球蛋白血症,B淋巴细胞减少症,视神经萎缩,水平眼球震颤,从小就有轻微的脾肿大和肝肿大。该病例在童年时期的血红蛋白水平和血小板计数正常。他首先在成年期发展了AIHA,然后在AIHA治疗期间出现了血小板减少症。明显的低丙种球蛋白血症和B淋巴细胞减少症的潜在机制难以捉摸。除了双等位基因NBAS突变,还检测到ANKRD26(c.2356C>T)基因中的种系突变。因此,在这种情况下,可能是自身免疫或ANKRD26突变介导的血小板减少症。
结果:他最初接受类固醇和间歇性静脉注射免疫球蛋白补充治疗。治疗后,他反应良好,血红蛋白和血清胆红素恢复正常.但患者随后除AIHA外还出现了严重的血小板减少症。然后,除了类固醇升级外,还每天给他服用avatrombopag。他再次对新的治疗方法作出反应,随着血红蛋白水平和血小板计数回到正常范围。现在,他正在每周降级avatrombopag和低剂量类固醇维持。
结论:此病例的表型表明c.3351G>ANBAS变体可能是致病性的,而c.2356C>TANKRD26变体是不可能的致病性的。即使在NBAS病患者中发生,AIHA也可能对类固醇反应良好。
BACKGROUND: Neuroblastoma amplified sequence (NBAS)-associated disease is an autosomal recessive disorder and a broad spectrum of clinical symptoms has been reported. However, autoimmune mediated hemolytic anemia (AIHA) is rarely reported in NBAS disease.
METHODS: A now 21-year-old male harbors heterozygous variants of c.6840G>A and c.335 + 1G>A and was found had retarded growth, hypogammaglobulinemia, B lymphopenia, optic atrophy, horizontal nystagmus, slight splenomegaly and hepatomegaly since childhood. This
case had normal hemoglobin level and platelet count in his childhood. He developed AIHA first in his adulthood and then thrombocytopenia during the treatment of AIHA. The mechanism underlying a
case with pronounced hypogammaglobulinemia and B lymphopenia is elusive. In addition to biallelic NBAS mutations, a germline mutation in the ANKRD26 (c.2356C>T) gene was also detected. So either autoimmune or ANKRD26 mutation-mediated thrombocytopenia is possible in this
case.
RESULTS: He was initially managed with steroid and intermittent intravenous immunoglobulin supplement. After treatment, he responded well with a normalization of hemoglobin and serum bilirubin. But the patient subsequently experienced severe thrombocytopenia in addition to AIHA. He was then given daily avatrombopag in addition to steroid escalation. He responded again to new treatment, with the hemoglobin levels and platelet counts went back to the normal ranges. Now he was on de-escalated weekly avatrombopag and low-dose steroids maintenance.
CONCLUSIONS: The phenotype of this
case indicates that c.335 + 1G>A NBAS variant is probably a pathogenic one and c.2356C>T ANKRD26 variant is improbably a pathogenic one. AIHA may respond well to steroid even when happened in patients with NBAS disease.