A novel Presenilin 2 mutation in two siblings with predominantly amnestic, early‐onset Alzheimer’s disease
Carl Froilan D. Leochico, Ana Luiza Pinto Oliveira, Mario Masellis, Sara Mitchell- Psychiatry and Mental health
- Cellular and Molecular Neuroscience
- Geriatrics and Gerontology
- Neurology (clinical)
- Developmental Neuroscience
- Health Policy
- Epidemiology
Abstract
Background
Familial, early‐onset Alzheimer’s Disease (AD) is a rare form of dementia resulting from autosomal dominant mutations in the amyloid precursor protein (APP), presenilin‐1 (PSEN1), or presenilin‐2 (PSEN2) genes with phenotypic diversity. PSEN2 mutations are rare and vary widely in age of onset.
Method
Case report and literature review.
Result
We report a novel PSEN2 variant (c.359T>G, p.Ile120Ser) that has been clearly segregated in two siblings in their fifties, presenting as predominantly amnestic AD. One of the siblings was also heterozygous in the PSEN1 gene (c.118_120del, p.Asp40del). There was no evidence of C9orf72 repeat expansion in either sibling. A third sibling has also started manifesting cognitive impairments. Their strong family history of cognitive dysfunction suggests that the PSEN2 mutation is pathogenic, and the causative variant has never been reported in Medline and the Alzgene genetic database of PSEN2.
Conclusion
As there are numerous PSEN2 mutations still incompletely characterized, there remains a need to systematically report patients either with familial or sporadic presentation and very early age of onset and classify their pathogenicity accordingly. Providing information about the genetic bases of AD can help allay the stress of patients and families about their diagnosis, individual risks, and possible care planning.