Additionally, in muscle biopsy samples of DM1 patients and in the HSALR mouse model showing increased expression of CELF1, reduced cyclin D3 levels and increased levels of glycogen synthase kinase 3 β (GSK3β), which is a known negative regulator of cyclin D3, were detected [162]. The gene discussed is GSK3B; the disease is myotonic dystrophy type 1.