KCTD1 and Intellectual disability: The other genes are potassium channel tetramerization domain containing 1 (KCTD1), zinc finger, myeloproliferative and mental retardation type 2 (ZMYM2)/zinc finger protein 198 (ZNF198), ZMYM3/ZNF261, ZMYM4/ZNF262 and glutamine-rich protein 1 (QRICH1) (Figure 5).