P530: Achieving consensus on a prenatal patient education resource about spina bifida

DNA samples (~8 Gb raw data/sample) also showed the absence of other known, heterozygous dominant or homozygous recessive, pathogenic variants and the presence of rare variants with uncertain significance.Molecular results supported different genetic mechanisms, Lamin A/C haploinsufficiency in Families A and B and dominant-negative or gain-of-function in Family C. Fibroblast reprogramming resulted in 20 different iPSC lines including nine LMNA mutationpositive (PATIENT) and 11 non-mutant (7 related and 4 unrelated CONTROL) iPSC lines.In total, ~140 independent iPSC clones (7 clones/iPSC line) were isolated, passaged, and stored frozen.Of these, 35 iPSC clones were characterized with 22 (63%) iPSC clones having normal results for both karyotype and pluripotency.Thus far, nine iPSC clones (four PATIENT and four CONTROL individuals) were differentiated into CM.For three iPSC clones (one PATIENT and one CONTROL individual from Family A), scRNA-seq analyses (>100,000 total high-quality cells) showed complex cell heterogeneity, and differential expression analyses (PATIENT vs CONTROL) showed cell type and lineage-specific dysregulation of multiple pathways including X-inactivation and genomic imprinting, cell differentiation, metabolism, and signaling.However, several factors limited the interpretation of these results.Conclusion: From three LMNA-related DCM families with different mutations, this study created and characterized a unique collection of patient-derived iPSC disease models for the investigation of mutation and cell type-specific mechanisms.Although initial studies provided insight into LMNA-related DCM pathogenesis, results consistent with transcriptome dysregulation and epigenomic failure, study design improvements are required to address weaknesses and limit confounding factors in modeling human cardiac disease using patient-derived iPSCs.