Molecular-genetic diagnostics of von Hippel-Lindau syndrome (VHL) in Bulgaria: first complex mutation event in the VHL gene

ABSTRACTVon Hippel-Lindau syndrome is an autosomal-dominant disease characterized by the formation of various tumours and cysts in many different parts of the body. Von Hippel-Lindau syndrome is caused by VHL gene mutations leading to production of impaired tumor suppressor Von Hippel-Lindau syndrome protein or its complete absence. Purpose: To study five patients with clinically suspected Von Hippel-Lindau syndrome, who were referred for molecular genetic testing. Methods: Sanger sequencing of the coding regions of the VHL gene. Results: Five clinically relevant germline mutations were detected. One of the pathogenic variants has not been previously reported. This novel mutation is a complex mutation event combining a duplication and an indel, rearranging exon 3 of the VHL gene - c. [516_517dupGTCAAGCCT; 532_542delCTGGACATCGTinsATTA], p. (Glu173Serfs*4). Conclusion: Overall, our results showed that the diagnosis of Von Hippel-Lindau syndrome in our country is difficult most probably because of its hetero...