Our results suggest a plausible explanation for with recent findings in Trisomy 21 (Down syndrome) pathology, in which HMGN1 is overexpressed, that developing and adult Down syndrome brains have dysregulated expression of genes associated with oligodendrocyte development and myelination in addition to alterations in the cerebellar cortex (Baxter et al., 2000; Mowery et al., 2018; Olmos-Serrano et al., 2016), highlighting the important roles that oligodendrocytes play in normal neurodevelopment and neurodevelopmental disorders (Jin et al., 2020). The gene discussed is HMGN1; the disease is Down syndrome.