For example, Tang et al. demonstrated that excessive Hcy induced by folate deficiency may lead to increased homocysteinylation of heterogeneous nuclear ribonucleoprotein E1(hnRNP-E1), which interacts with its mRNA cis-element and forms a positive feedback loop, eventually resulting in accumulation of hnRNP-E1. The gene discussed is PCBP1; the disease is folate deficiency.