Identification of the underlying cause of intellectual disability (ID) is important as it improves genetic counselling, management, adaptation; yet its etiologic heterogeneity is challenging and often leads to an expensive work-up.

To improve this diagnostic trajectory, the multidisciplinary Complex Diagnostic Clinic (CDC) was established for ID patients with unexplained complex systemic and/or neurologic features that were referred to the CDC and evaluated by three medical specialists followed by multi-disciplinary rounds. Analyses included surveys and interviews, (retrospective) chart review, costs calculations and comparison.

24 children (9 male) were evaluated during seven clinics held over 16 months. The average patient age was 7 years 11 months (range 9 months-18 years). All the children had previously been seen by 2–10 specialist services. The diagnostic yield of the CDC was higher than expected with confirmed and working diagnoses in 11 (46%) and 9 (38%) children respectively. Cost-savings included fewer trips to hospital and fewer tests via more streamlined evaluations. Positive feedback was received from both families and medical professionals.

The CDC represents an innovative model of personalized care. Specialist collaboration in the interpretation of relevant clinical, biochemical and genomic data resulted in diagnoses, where none had previously been possible.