Kleefstra Syndrome 1, also known as 9q subtelomeric deletion syndrome, is related to kleefstra syndrome due to a point mutation and kleefstra syndrome 2, and has symptoms including seizures An important gene associated with Kleefstra Syndrome 1 is EHMT1 (Euchromatic Histone Lysine Methyltransferase 1), and among its related pathways/superpathways are Chromatin organization and Cellular Senescence. Affiliated tissues include heart and testis, and related phenotypes are intellectual disability and aphasia