49 Case Study: Cognitive Deficits Associated with Norrie Disease

Abstract

Objective:

Norrie disease is a rare, x-linked recessive genetic disorder associated with an NDP gene mutation. Males are predominantly affected. Typical symptoms include vision loss around the time of birth and progressive hearing loss. Cognitive and behavioral abnormalities also occur in 30-50% of individuals, including developmental delays, intellectual disability, cognitive regression, psychosis, and aggression. There is limited research, however, examining the neuropsychological deficits in adulthood resulting from Norrie disease, especially with neuropsychological data and in individuals without other neurological manifestations of the disease, such as seizures. Here, we present the neurocognitive profile of a patient with Norrie disease who presented for a cognitive evaluation in adulthood due to report of more recent memory decline.

Participants and Methods:

Mr. Smith is a Caucasian male in his mid-40's who previously underwent genetic testing and was subsequently diagnosed with Norrie disease. As a result of his diagnosis, he experienced complete vision loss since birth and bilateral hearing loss that began in childhood and gradually worsened in adolescence. Medical history was otherwise unremarkable. Developmental milestones were met on time. Historical intelligence testing conducted in elementary school revealed borderline on one intelligence test to high average performance on other intelligence tests. However, he was retained grades several times due to factors such as behavioral disruptions and academic difficulties. He had been employed as an assembly line worker for many years, but had not worked for 10 years prior to the neuropsychological evaluation. Emotionally, he had a longstanding history of anxiety and endorsed mild anxiety and depression at the time of the evaluation. The patient first noticed memory difficulties in adolescence then noticed further decline four years prior to the neuropsychological evaluation (around when he received a left-ear cochlear implant), which had remained stable since onset.

Results:

In the context of low average premorbid intellectual functioning, Mr. Smith's neurocognitive profile was notable for difficulties with alphanumeric set-shifting and abstract thinking, with otherwise preserved cognitive functioning. Weaknesses observed on testing may have represented longstanding weaknesses and did not rise to the level of a cognitive disorder. Affective distress was also suspected to have accounted for some of the cognitive lapses the patient reported experiencing with day-to-day functioning.

Conclusions:

The current poster aims to contribute to the limited body of literature examining neuropsychological deficits in adulthood resulting from Norrie disease. This is especially critical given that the long-term cognitive dysfunction of this disorder is relatively unknown and could negatively impact patients' quality of life over time.