Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that displays a wide spectrum of clinical manifestations, often affecting multiple organs including the kidneys, brain, lungs, and skin. A pathogenic mutation in either the TSC1 or TSC2 gene can be detected in almost 85% of the cases, with mosaicism accounting for about half of the remaining cases. We report a case of TSC diagnosed clinically, requesting genetic counselling regarding reproductive risks. No mutation was identified on initial testing of peripheral blood; however, mosaicism for a likely pathogenic frameshift variant in TSC2 was detected at a level of 15% in renal angiomyolipoma tissue. Despite widespread clinical manifestations of TCS, this variant was not detected in skin fibroblasts or saliva, raising the possibility this is an isolated somatic mutation in renal tissue with the underlying germline mutation not yet identified. This case highlights the difficulties when counselling patients with mosaicism regarding their reproductive risks and prenatal diagnostic options.
Mol Syndromol

中文翻译：

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肾组织中 TSC2 变异的结节性硬化症患者在植入前遗传学诊断中的潜在缺陷

结节性硬化症 (TSC) 是一种常染色体显性遗传病，临床表现广泛，常累及肾脏、脑、肺和皮肤等多个器官。在几乎 85% 的病例中可以检测到TSC1或TSC2基因的致病突变，其中镶嵌现象约占其余病例的一半。我们报告了一个临床诊断的 TSC 病例，要求就生殖风险进行遗传咨询。外周血初步检测未发现突变；然而，TSC2 中可能的致病性移码变异的嵌合在肾血管平滑肌脂肪瘤组织中检测到 15% 的水平。尽管 TCS 具有广泛的临床表现，但在皮肤成纤维细胞或唾液中未检测到这种变异，这增加了这是肾组织中一种孤立的体细胞突变的可能性，其潜在的种系突变尚未确定。这个案例凸显了在向镶嵌症患者咨询生殖风险和产前诊断选择时遇到的困难。
摩尔综合征