Transcriptomic Profiling of Monozygotic Twins with Type 1 Gaucher Disease.

Background: Gaucher disease (GD) arises from pathogenic variants in the GBA1 gene and is known for its wide range of clinical presentations-a variability that genotype alone cannot adequately account for. Objective: This study aimed to explore transcriptomic factors that might help explain why two genetically identical twins with type 1 GD developed noticeably different clinical outcomes. Methods: We isolated peripheral blood mononuclear cells from both twins and two age-matched controls, then differentiated them into macrophages in vitro before conducting RNA sequencing. Gene expression differences were analyzed using established bioinformatics pipelines, and a subset of genes were subsequently assessed by quantitative real-time PCR (qRT-PCR) to confirm the sequencing findings. Results: Both twins shared a GD-associated transcriptional signature broadly reflecting immune activation and lysosomal stress. Interestingly, the twin who experienced systemic complications had a relative enrichment of interferon-responsive transcripts, while the less severely affected twin showed more pronounced suppression of small nucleolar RNA clusters. That said, neither difference held up after correcting for multiple comparisons, so these patterns are best viewed as exploratory trends rather than definitive findings. The qRT-PCR results lend partial support to this picture: stress- and immune-related genes (DDIT4, RPH3A, SAMSN1) trended toward higher expression in patients versus controls, and interferon-stimulated genes (ISG15, RSAD2, IFI44L) were more elevated in M2 than in M1. Conclusions: Taken together, these findings suggest that factors beyond genetics-whether epigenetic, environmental, or otherwise-may play a meaningful role in shaping how GD manifests differently even between individuals with identical DNA. Although the data are preliminary, they point to transcriptomic profiling, paired with targeted validation, as a useful starting point for building hypotheses about why this disease looks so different from one patient to the next, even when the underlying mutation is the same.