Proteus Syndrome Phenotype and Genetic Etiology Study

The purpose of this project is to specifically delineate the phenotype and natural history and genetic etiology of Proteus syndrome (PS) and other overgrowth disorders hypothesized to be in the PI3K/AKT pathway. As we have determined the molecular cause of PS and the related disorder of fibroadipose overgrowth, our main objectives moving forward include genotype-phenotype correlations, identifying quantifiable phenotypic characteristics in patients and measuring changes in these characteristics over time, developing potential biomarkers for future therapeutic research, and using our new molecular insights to expand our understanding of both PS and related overgrowth disorders. The natural history and specific phenotypic characteristics of patients with PS and selected other overgrowth disorders will be determined by clinical assessment and longitudinal follow-up of patients, which includes patients who have been exposed to therapeutic agents, such as an AKT inhibitor. Subjects will be screened for eligibility using published diagnostic criteria for PS; screening for AKT1 and other pathway gene variants may be used in patients with overlapping phenotypes. The discovery of the AKT1 activating variant in patients with this disease provides an attractive target for directed treatment for this devastating disorder. This protocol aims to aid in identifying individuals with molecularly-confirmed AKT1 variants who may be candidates for pharmacologic interventional studies. We also propose to expand our clinical ascertainment to determine the full range of PS/AKT1 activating variant phenotypes and to study other overlapping conditions. The etiology of these disorders will be studied using candidate gene analysis (primarily based on the PI3K/AKT pathway) and possibly exome and whole genome sequencing, performed as part of protocol 10-HG-0065.