This association is particularly evident in individuals with WAGR syndrome (Wilms' tumor, aniridia, genitourinary anomalies, and intellectual disability), where those with heterozygous BDNF deletions exhibit approximately half the serum BDNF levels and a higher incidence of childhood-onset obesity, compared to those with an intact BDNF sequence (112). The gene discussed is BDNF; the disease is Wilms tumor.