Deletions in SYNJ1, ITSN1, SLC5A3/SMIT1, and KCNE2, located in the distal part of 21q22.11, are associated with neurobehavioral symptoms [34,35], whereas deletions in the critical region 21q22.11, such as KCNE1 and DSCR1, lead to congenital heart defects [35]. The gene discussed is SLC5A3; the disease is congenital heart disease.