Studio archivistico genealogico di una famiglia portatrice di una nuova mutazione del gene PSEN2 (A85V)

Aim:Alzheimer disease (AD) hereditary is most often caused by mutations in the gene PSEN1 unlike the mutations in the PSEN2 gene which are rare.We describe an archival and genealogical research in Italian family with hereditary dementia associated with a novel mutation in the presenilin 2 gene’s disease.Methods:Clinical investigations of the diseased subjects; interviews with relatives; studies of medical records; pedigree analysis; and neuroradiologic, neuropathologic studies were carried out in the pedigree.Results:Genetic analysis showed a novel PSEN2 A85V mutation present in the proband and in all analyzed affected members, in a subject presenting with an amnesic mild cognitive impairment, and in a young, still asymptomatic subject. The proband showed a clinical phenotype indicative of Lewy body dementia and the neuropathologic examination demonstrated the presence of unusually abundant and widespread cortical Lewy bodies in addition to the hallmark lesions of AD. Other affected members exhibited a clinical phenotype typical of AD.Conclusion:Our findings add complexity to the spectrum of atypical phenotypes associated with presenilin mutations and should then be taken into account when considering the nosography of neurodegenerative diseases. They also support previous data that specific mutations of genes associated with familial Alzheimer disease may influence the presence and extent of Lewy bodies.