PUM1 and cerebellar ataxia: Alterations in the human gene coding Teneurin Transmembrane Protein 4 (TENM4, shares high homology with fly Ten-a and Ten-m) are known to cause hereditary essential tremor-5, while human neuroligins NLGN1, NLGN3 and NLGN4X were linked to autism/Asperger syndrome and encode orthologs to fly Nlg2. Finally, alterations in human orthologs to fly Pum (PUM1/2), beta-Spec (SPTBN1/2) and Ank2 (ANK1/2/3) have been associated with Ataxia-like phenotypes and mental retardation.