KMT2D and congenital isolated hyperinsulinism: Additionally, CHI can be part of genetic syndromes, such as Beckwith-Wiedemann syndrome (BWS), which is caused by genetic or epigenetic changes in the imprinted 11p15.5 region, including paternal uniparental disomy (UPD11p), alterations in methylation patterns, or pathogenic variants in CDKN1C, sometimes in combination with paternally inherited recessive variants of ABCC8 or KCNJ11. CHI is also associated with Kabuki syndrome, caused by KMT2D and KDM6A mutations, usually in a mosaic pattern.