These results were extremely important, not only to disclose the clinical characteristics and the GRN mutation spectrum of the patients from the central/north region of Portugal but also to allow their enrollment (both asymptomatic-GRN mutation carriers and symptomatic-GRN mutation patients) in an ongoing clinical trial which is testing a new gene-specific therapy that aims to normalize PGRN deficiency. Here, GRN is linked to hyperinsulinemic hypoglycemia, familial, 4.