PTPRR and cerebellar ataxia: According to the current knowledge, the PTPRR gene encodes a transmembrane protein known as protein tyrosine phosphatase receptor type R. It may be of particular relevance to the motor coordination function of the central nervous system and may be involved in oncogenesis in the digestive system, as gene knockout mice display an ataxia phenotype while PTPRR are epigenetically silenced in colorectal carcinoma (Menigatti et al., 2009).