A 14-year-old male presented with abdominal pain. Imaging illustrated a left-sided adrenal mass; he underwent a left nephrectomy, confirming an extra-adrenal PGL. Germline genetic testing revealed a heterozygous, likely pathogenic mutation in the SDHB gene. The patient’s family subsequently underwent genetic testing; his mother and sister were both positive for the familial SDHB mutation. Cascade testing for the proband’s maternal aunt and maternal grandparents was negative for the familial mutation. SNP genotyping was used to confirm relationships. This is the second reported case of a de novo SDHB gene mutation and the first reported case of a confirmed de novo mutation in a patient who was not the initial proband. As SDHB-associated PGLs and PCCs are expected to be more aggressive and malignant, it is imperative to identify patients with SDHB mutations early. Given that many patients with germline mutations have no family history of PGL of PCC, the possibility of de novo mutations must be considered. Further studies are needed to determine the rate of de novo mutation in SDHB and other SDH-complex genes. Up to 41% of patients with paragangliomas (PGL) or pheochromocytomas (PCC) have an identifiable hereditary cancer predisposition syndrome. Mutations in 12 genes are known to increase the risk of PGL and/or PCC; however, the de novo rate is mostly unknown. Only one case report exists of a de novo SDHB mutation. We present the second case of a family with a de novo SDHB mutation.

中文翻译：

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患有肾上腺旁神经节瘤的家庭的从头SDHB基因突变。

一名14岁男性出现腹痛。影像学检查显示左侧肾上腺肿块。他接受了左肾切除术，证实了肾上腺外PGL。胚芽基因测试显示SDHB基因杂合，可能是致病性突变。患者的家属随后接受了基因检测；他的母亲和妹妹均为家族性SDHB突变阳性。对先证者的母亲姨妈和祖父母的父母进行级联测试对家族变异为阴性。SNP基因分型被用于确认关系。这是第二例从头报道的SDHB基因突变病例，也是第一例在不是最初的先证者的患者中证实从头突变的病例。如预计与SDHB相关的PGL和PCC会更具侵略性和恶性，因此必须尽早识别出具有SDHB突变的患者。鉴于许多具有种系突变的患者都没有PCC的PGL家族史，因此必须考虑从头突变的可能性。需要进一步的研究来确定SDHB和其他SDH复合基因中从头突变的速率。高达41％的神经节旁瘤（PGL）或嗜铬细胞瘤（PCC）患者患有可识别的遗传性癌症易感综合征。已知12个基因的突变会增加PGL和/或PCC的风险；但是，从头开始率大多未知。只有一个病例报告存在从头SDHB突变。我们介绍了从头SDHB突变家庭的第二例。