Given that the MMRN1 gene dosage has also been implicated in cognitive decline (Nishioka et al., 2006; Fuchs et al., 2007; Mutez et al., 2011), it will be interesting to perform a neuropsychological characterization of the PARK4 heterozygotes in this family in the future, but currently the cognitive score in one patient is still unaffected (mini-mental state examination score, MMSE=30). This evidence concerns the gene MMRN1 and Mental deterioration.