Sofia B Lizarraga, Li Ma, Abbie M Maguire, Laura I van Dyck, Qing Wu, Qing Ouyang, Brian C Kavanaugh, Dipal Nagda, Liane L Livi, Matthew F Pescosolido, Michael Schmidt, Shanique Alabi, Mara H Cowen, Paul Brito-Vargas, Diane Hoffman-Kim, Ece D Gamsiz Uzun, Avner Schlessinger, Richard N Jones, Eric M Morrow
Christianson syndrome (CS), an X-linked neurological disorder characterized by postnatal attenuation of brain growth (postnatal microcephaly), is caused by mutations in SLC9A6 , the gene encoding endosomal Na+ /H+ exchanger 6 (NHE6). To hasten treatment development, we established induced pluripotent stem cell (iPSC) lines from patients with CS representing a mutational spectrum, as well as biologically related and isogenic control lines. We demonstrated that pathogenic mutations lead to loss of protein function by a variety of mechanisms: The majority of mutations caused loss of mRNA due to nonsense-mediated mRNA decay; however, a recurrent, missense mutation (the G383D mutation) had both loss-of-function and dominant-negative activities...
February 10, 2021: Science Translational Medicine