CLN-1 and CLN-5, genes for infantile and variant late infantile neuronal ceroid lipofuscinoses, are expressed in the embryonic human brain.

Mutations in the CLN-1 and CLN-5 genes underlie the infantile, and Finnish variant of the late-infantile, neuronal ceroid lipofuscinoses, respectively. These disorders are characterized by a massive neuronal death early in childhood. We have studied mRNA and protein expression of CLN-1 and CLN-5 in embryonic human brains. The spatial and temporal distributions of CLN-1 and CLN-5 were similar in the embryonic human brain. Both genes are expressed at the beginning of cortical neurogenesis, and this expression increases as cortical development proceeds. In the developing cortical plate, expression is found in postmitotic migrating neuroblasts and neuroblasts that have completed migration. Expression was intense also in cells of the thalamus as well as in the future Purkinje cell layer of the cerebellum. These findings indicate that expression of CLN-1 and CLN-5 may be significant for development of a wide range of maturating neurons. Copyright 2000 Wiley-Liss, Inc.