Given the wide clinical spectrum of STXBP1-related diseases, a genotype-phenotype correlation is difficult to achieve: haploinsufficiency of the gene associated with a dominant-negative effect has been proposed as the primary pathogenic mechanism behind STXBP1 encephalopathy, potentially explaining the complex expression of pathogenic variants of this gene (64, 66). The gene discussed is STXBP1; the disease is Encephalopathy.