Multifocal Paraganglioma and Pheochromocytoma Due to Truncated SDHD Mutation.

OBJECTIVE:Pheochromocytoma and paraganglioma (PPGL) are rare autosomal dominant disorders derived from the neural crest chromaffin tissues of the autonomic nervous system. The succinate dehydrogenase complex subunit D (SDHD) gene has been implicated as one of the pathogenic genes. Although more than 100 SDHD mutations have been reported, the phenotype-genotype association remains unclear. METHODS:We reported a case of a patient who presented with multifocal PPGLs and with a rare SDHD mutation, and reviewed the phenotype-genotype association of SDHD. RESULTS:We identified a pathogenic variant of SDHD (c.170-1G>T, NM_003002.3), which caused the complete deletion of exon 3 in the transcript and resulted in a shorter and unstable SDHD mRNA. And truncated SDHD mutations were prone to cause multifocal PPGL, whereas missense SDHD mutations usually caused unifocal lesions. CONCLUSION:This is the first report linking the c.170-1G>T variant to multifocal tumors. We recommend whole-body imaging examinations and close, regular follow-up for these patients, given the risk of multifocal tumor development.