In Reply We appreciate the astute comments from Cullum and Weiner. The neuropsychological evaluation of our patient included the standard tests performed on patients coming to the University of California, San Francisco, Memory and Aging Center.1 His performance on some items was indeed below average. It is important to note that the patient came from a socially deprived environment and had profound disadvantages during childhood. Additionally, dyslexia was suspected from our clinical history. He had no history of progressive cognitive or functional deterioration, and we did not consider it correct to label him as cognitively impaired. Of seminal importance in this case is the observation that the total absence of apolipoprotein E, normally present in brain and with demonstrated roles in the transport of myelin lipids, can be associated with relatively normal development and adulthood without critically impairing neurological functions. We will, of course, continue to monitor him for evidence of any changes in his neurological and psychological functioning.
Malloy M, Miller B, Kane J. Apolipoprotein E and Neurocognitive Function—Reply. JAMA Neurol. 2015;72(4):479. doi:10.1001/jamaneurol.2014.4699