New Options for People with a Genetic Cause for Obesity. Obesity is a growing issue in populations all over the world and comes with many comorbidities that challenge both patients and health systems. Treatment options, like bariatric surgery, are available for these individuals but are not always effective. A percentage of patients have a genetic disorder causing their obesity, and treatment must be tailored to their needs. The Obesity Genetics Research Group at Amsterdam UMC is a collaboration between clinical, molecular and functional researchers working on Obesity and its associated health problems. This group of researchers shares an ambition to explore the underlying pathogenesis of obesity, including genetic analysis of patients with obesity and translating the scientific results into daily practice with the ultimate aim to offer personalised medicine for affected individuals. Though obesity is a common disease, only a small percentage of patients have a genetic disorder that causes their obesity. These patients can have mutations in the system that controls appetite and metabolism, the leptin-melanocortin pathway. In these instances, obesity is their main health problem. Obesity can also be a part of syndromes with an intellectual disability or congenital anomalies - this is known as ‘syndromic obesity’. Since genetic testing obesity is not part of routine medical care and there is a lack of access to genetic testing in many countries, it is important to know which patients with obesity should receive genetic testing. As published in an award-winning article - titled “Genetic obesity: next-generation sequencing results of 1230 patients with obesity” - research conducted by the group found that diagnosis is most effective in children with very early-onset obesity – conversely, diagnostic yield in bariatric surgery subgroups is relatively low. The Netherlands is the ideal place for this research - here genetic tests are a diagnostic service, providing accredited diagnostic results that can be used in a research environment. This means the group has a large collection of patient cohorts, can offer segregation analysis as part of the diagnostic service - resulting in a higher diagnostic yield and fewer Variants of unknown significance. Within the network, there are plenty of opportunities to further interpret results by performing additional functional analyses. Receiving the diagnosis is the first step for patients with rare genetic obesity disorders. After that, the aim is to lead them to personalized treatment. To achieve this, the research group has international collaborations studying the complete spectrum of obesity treatment -from pharmacological therapy and bariatric surgery to psychological support in dealing with an insatiable hunger. These research areas also involve a wide range of clinical trials, meaning the work the group is doing will have a major impact on obesity treatment for years to come.