Familial Dysautonomia (FD) Human Embryonic Stem Cell Derived PNS Neurons Reveal that Synaptic Vesicular and Neuronal Transport Genes Are Directly or Indirectly Affected by IKBKAP Downregulation.

A splicing mutation in the IKBKAP gene causes Familial Dysautonomia (FD), affecting the IKAP protein expression levels and proper development and function of the peripheral nervous system (PNS). Here we found new molecular insights for the IKAP role and the impact of the FD mutation in the human PNS lineage by using a novel and unique human embryonic stem cell (hESC) line homozygous to the FD mutation originated by pre implantation genetic diagnosis (PGD) analysis. We found that IKBKAP downregulation during PNS differentiation affects normal migration in FD-hESC derived neural crest cells (NCC) while at later stages the PNS neurons show reduced intracellular colocalization between vesicular proteins and IKAP.

IKAP/hELP1 down-regulation in neuroblastoma cells causes enhanced cell adhesion mediated by contactin overexpression.

A splicing mutation in the IKBKAP gene encoding the IKAP/hELP1 (IKAP) protein was found to be the major cause of Familial Dysautonomia (FD). This mutation affects both the normal development and survival of sensory and sympathetic neurons of the peripheral nervous system (PNS). To understand the FD phenotype it is important to study the specific role played by IKAP in developing and mature PNS neurons.