A GTTA sequence was inserted at position 2178 in exon 17 (c.2178_2179) to mimic the human mutation 2211insGTTA found in patients with mosaic variegated aneuploidy (MVA) syndrome. Cre-mediated recombination removed the neo cassette upstream of the modified exon 17. Western blot analysis confirmed reduced protein expression in mouse embryonic fibroblasts.