Natural History of Familial Carcinoid Tumor

Study Description: This study is designed as a prospective evaluation for diagnostic screening, genotyping and natural history of participants belonging to kindreds with familial carcinoid tumor. Objectives: Primary Objective: Study the natural history of familial carcinoid tumors: incidence, age of onset, symptoms, the appropriate diagnostic (biochemical and imaging) modalities, location, histology and metastatic potential of the tumors, metabolic sequelae of the tumor, and clinical and biochemical prognostic factors. Secondary Objectives: * Screen for occult disease and determine whether early detection affects the natural history of the disease. * Compare the sensitivity and specificity of various imaging tomography (CT) with IV contrast and oral Breeza, 18F-DOPA PET/CT scan, \[68Ga\] DOTATATE PET/CT scan and endoscopic modalities for diagnosing and following carcinoid tumors. * Collect tumor specimens for histologic evaluation, culturing of intestinal organoids, and genotyping (including DNA and RNA sequencing). * Sequester DNA from peripheral blood for genotyping (including sequencing) with the intention of localizing a susceptibility gene/s responsible for the familial occurrence of the disease.