Maturity-onset diabetes of the young type 5 (MODY5) presents with incomplete penetrance and phenotypic heterogeneity, often resulting in misdiagnosis with other renal disorders. Hence, HNF1β mutation detection rates in MODY5-like patients are low (∼15%) and standards for mutation analysis are lacking. Faguer et al. established a composite score evaluating the most frequent and specific features of MODY5. Further, they tested an algorithm that provides a rational for genetic testing and improves HNF1β mutation detection rates.