**Laura Lossi 1, Claudia Castagna 1, Alberto Granato 2,\* and Adalberto Merighi 1,\***


Received: 9 October 2019; Accepted: 28 November 2019; Published: 1 December 2019

**Abstract:** The first description of the *Reeler* mutation in mouse dates to more than fifty years ago, and later, its causative gene (*reln*) was discovered in mouse, and its human orthologue (*RELN*) was demonstrated to be causative of lissencephaly 2 (LIS2) and about 20% of the cases of autosomal-dominant lateral temporal epilepsy (ADLTE). In both human and mice, the gene encodes for a glycoprotein referred to as reelin (Reln) that plays a primary function in neuronal migration during development and synaptic stabilization in adulthood. Besides LIS2 and ADLTE, *RELN* and/or other genes coding for the proteins of the Reln intracellular cascade have been associated substantially to other conditions such as spinocerebellar ataxia type 7 and 37, *VLDLR*-associated cerebellar hypoplasia, *PAFAH1B1*-associated lissencephaly, autism, and schizophrenia. According to their modalities of inheritances and with significant differences among each other, these neuropsychiatric disorders can be modeled in the homozygous (*reln*−/−) or heterozygous (*reln*+/−) *Reeler* mouse. The worth of these mice as translational models is discussed, with focus on their construct and face validity. Description of face validity, i.e., the resemblance of phenotypes between the two species, centers onto the histological, neurochemical, and functional observations in the cerebral cortex, hippocampus, and cerebellum of *Reeler* mice and their human counterparts.

**Keywords:** reelin; LIS2; ADLTE; autism; schizophrenia; translational models; GABAergic interneurons; dendritic spines; forebrain; cerebellum
