SYT1 and Cognitive impairment: Since this syt mutation results in the most severe deficits in an animal system [37] and is located in the syt1 gene, which is preferentially expressed in the cerebral hemispheres [15, 16], it is not surprising that this patient experienced extreme cognitive deficits as well as the most severe motor deficits observed in a synaptotagmin human disease to date [32].