low IKAP expression has been found to have a profound effect on transcription of genes involved in cell migration. In yeast, experimental data shows the elongator complex functioning in a variety of processes — from exocytosis to tRNA modification. This finding demonstrates that the function of the elongator complex is not conserved among species. Related conditions Familial Dysautonomia Familial dysautonomia (also known as “Riley-Day syndrome”) is a complex congenital neurodevelopmental disease, characterized by unusually low numbers of neurons in the sensory and autonomic nervous systems. The resulting symptoms of patients include gastrointestinal dysfunction, scoliosis, and pain insensitivity. This disease is especially prevalent in the Ashkenazi Jewish population, where 1/3600 live births present familial dysautonomia. By 2001, the genetic cause of familial dysautonomia was localized to a dysfunctional region spanning 177kb on chromosome 9q31. With the use of blood samples from diagnosed patients, the implicated region was successfully sequenced. The IKBKAP gene, one of the five genes identified in that region, was found to have a single-base mutation in over 99.5% of cases of familial dysautonomia seen. The single-base mutation, overwhelmingly noted as a transition from cytosine to thymine, is present in the 5’ splice donor site of intron 20 in the IKBKAP pre-mRNA. This prevents recruitment of splicing machinery, and thus exon 19 is spliced directly to exon 21 in the final mRNA product – exon 20 is removed from the pre-mRNA with the introns. The unintentional removal of an exon from the final mRNA product is termed exon skipping. Therefore, there is a decreased level of functional IKAP protein expression within affected tissue. However, this disorder is tissue-specific. Lymphoblasts, even with the mutation present, may continue to express some functional IKAP protein. In contrast, brain tissue with the single-base mutation in the IKBKAP gene predominantly express a resulting truncated, mutant IKAP protein which is nonfunctional. The exact mechanism for how the familial dysautonomia phenotype is induced due to reduced IKAP expression is unclear; still, as a protein involved in transcriptional regulation, there have been a variety of proposed mechanisms. One such theory suggests that critical genes in the development of wild-type sensory and autonomic neurons are improperly transcribed. An extension of this research suggests that genes involved in cell migration are impaired in the nervous system, creating a foundation for this disorder. In a small number of reported familial dysautonomia cases, researchers have identified other mutations that cause a