However, Northern blot analyses of liver, kidney and brains of wild‐type and homozygous mutant Cln3Dex7/8 knock‐in mice revealed decreased yet stable levels of mutant RNA consistent with the presence of CLN3 mRNA in patient tissue (Cotman et al., 2002; "Isolation of a novel gene underlying Batten disease, CLN3. This evidence concerns the gene CLN3 and juvenile neuronal ceroid lipofuscinosis.