Quantitative studies indicate an overrepresentation of ASD in individuals with GD. This study aims to determine the prevalence of autistic traits or ASD in adults with GD using two different data collection methods: (1) cross-sectional data using the social responsiveness scale-adults (SRS-A) and the autism quotient (AQ) (n = 63). (2) Clinical chart data (n = 532). Mean SRS-A scores were significantly higher compared to a norm population. Almost 5% of the patients with GD scored above the cut-off as measured by the AQ. In 32 patients (6%), a certain ASD diagnosis was found in the patient files, which is sixfold higher compared to the general population. Significantly more "birth assigned male" were affected compared to "birth assigned female".