Despite the associated effects of Kleefstra, there is insubstantial information regarding to the lethality of Kleefstra's. Most of the documented cases are de novo with the exception of one case due to hereditary factors; however, some cases may be a result of chromosomal translocations. In the exception case, the mother transferred the EHMT1 point mutation on to her child as she was a carrier of this gene defect. According to Mitter, et al. (2012), the mother's phenotype of the NM_024757.4:c.2712+1G>A mutation displayed mosaicism at certain tissues. This mutation resulted in the disregard of exon 18 on the EHMT1 gene, as opposed to removing it through the spliceosomes. In another transcript, however, an intron was placed between exon 18 and 19 of the EHMT1 gene. The combination of the intron insertion and the mosaicism in the mother was transferred to the child, resulting in the pathogenesis of the disease. In the past, research showed that the austerity of the disease was directly proportional to the number of EHMT1 deletions prevalent in an individual. The greater the deletions, the greater the severity of the condition. However, in recent studies,<unk>  occurs when the EHMT1 gene is non-functioning, as opposed to strictly deletion.
9q34 deletion syndrome
13q deletion syndrome
22q13 deletion syndrome
2q37 deletion syndrome
22q11.2 distal deletion syndrome
1q21.1 deletion syndrome
1p36 deletion syndrome
17q12 microdeletion syndrome