Characteristics of induced pluripotent stem cells from clinically divergent female monozygotic twins with Danon disease.

Rationale Induced pluripotent stem cells (iPSCs) have been generated from patients with various forms of disease, including Danon disease (DD); however, few reports exist regarding disease-specific iPSCs derived from clinically divergent monozygotic twins. Objective We examined the characteristics of iPSCs and iPSC-derived cardiomyocytes (iPSC-CMs) generated from clinically divergent monozygotic female twins with DD. Methods and results We generated iPSCs derived from T-cells isolated from clinically divergent, 18-year-old female twins with DD harboring a mutation in LAMP2 at the intron 6 splice site (IVS6 + 1_4delGTGA). Two divergent populations of iPSCs could prepare from each twin despite of their clinical divergence: one with wild-type LAMP2 expression (WT-iPSCs) and a second with mutant LAMP2 expression (MT-iPSCs). The iPSCs were differentiated into iPSC-CMs and then autophagy failure was observed only in MT-iPSC-CMs by electron microscopy, tandem fluorescent-tagged LC3 analysis, and LC3-II western blotting. Under these conditions, X-chromosome inactivation (XCI) was determined by PCR for the (CAG)n repeat in the androgen receptor gene, revealing an extremely skewed XCI pattern with the inactivated paternal wild-type and maternal mutant X-chromosomes in MT-iPSCs and WT-iPSCs, respectively, from each twin. Conclusion Regardless of their clinical differences, we successfully established two sets of iPSC lines that expressed either wild-type or mutant LAMP2 allele from each monozygotic twin with DD, of which only the populations expressing mutant LAMP2 showed autophagic failure. [ABSTRACT FROM AUTHOR]