Malignantextra-adrenalpheochromocytomacausedbyan SDHB intronicvariationleadingtoa54-bpdeletioninexon4

In the last few years several papers have re- portedontheassociationbetweenmutationsofthegenes encodingthestructural(SDHC, SDHD)andcatalytic(SDHB) subunits of succinate dehydrogenase and the occurrence of hereditary pheochromocytomas/paragangliomas (Pheo/PGL) syndromes. We diagnosed a malignant extra- adrenal Pheo in a 38-yr-old man with abdominal lesions; manyareasofincreaseduptakeatoctreoscanscintigraphy in the skeleton indicated metastatic disease. We then ap- proachedgeneticanalysisthroughthescreeningofthe SD- HB, SDHC, and SDHD genes. Here we report a heterozy- gous G>A transversion at position +1 of intron 4 of SDHB gene. To clarify this mutation we performed cDNA analy- sis by RT-PCR and we assume that the splice site mutation in intron 4 abolishes the consensus splice donor sequence leadingtoanin-framedeletionof18aminoacid.Thisfind- ing indicates once again that SDHB mutations could pre- disposeto malignantPheo. (J.Endocrinol.Invest.32:111-114,2009) ©2009,EditriceKurtis