A novel presenilin 1 mutation (L174 M) in a large Cuban family with early onset Alzheimer disease

• Published in: Neurogenetics Vol. 4; no. 2; pp. 97 - 104
• Main Authors: BERTOLI AVELLA, A. M, MARCHECO TERUEL, B, LLIBRE RODRIGUEZ, J. J, GOMEZ VIERA, N, BORRAJERO MARTINEZ, I, SEVERIJNEN, E. A, JOOSSE, M, VAN DUIJN, C. M, HEREDERO BAUTE, L, HEUTINK, P
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01-10-2002; Springer Nature B.V
• Subjects: Age of Onset; Alzheimer Disease - genetics; Alzheimer Disease - pathology; Alzheimer's disease; Amino Acid Sequence; Apolipoproteins E - genetics; Biological and medical sciences; Conserved Sequence; Cuba; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Dementia; Family Health; Female; Genetic Markers; Genotype; Heredity; Hispanic Americans - genetics; Humans; Male; Medical sciences; Membrane Proteins - genetics; Molecular Sequence Data; Mutation; Neurology; Pedigree; Point Mutation; Presenilin-1; Cuba; Human; Nervous system diseases; Alzheimer disease; Family study; Pathogenesis; Clinical form; Presenilin; Genetic determinism; Cerebral disorder; Genetic disease; Age of onset; Central nervous system disease; Early; Degenerative disease; Mutation
• ISSN: 1364-6745; 1364-6753
• DOI: 10.1007/s10048-002-0136-6

We studied a Cuban family with presenile dementia (autosomal dominant) consisting of 281 members within six generations, the proband descended from a Spanish founder. Mean age at onset was 59 years of age. Memory impairment was the main symptom in all patients, additionally, ischemic episodes were described in 4 (n = 18) patients. Neuropathological examination of brain material (1 patient) revealed neuronal loss, amyloid plaques, and neurofibrillary tangles. Thirty DNA samples were genotyped (regions on chromosome 1, 3, 10, 12, 14, 17, 19, 20, and 21). A maximum Lod score of 3.79 at theta = 0 was obtained for marker D14S43, located in a 9-cM interval in which all patients shared the same haplotype. Sequencing of the PSEN1 gene revealed a heterozygous base substitution, C520A (exon 6), which is predicted to cause an amino acid change from leucine to methionine in the TMIII of the presenilin 1 protein. The mutation was found to co-segregate with the disease phenotype and the associated disease haplotype. The C --> A change was not observed in 80 control chromosomes from the Cuban population. Leucine at position 174 is highly conserved among species and is identical in presenilin 1 and presenilin 2 proteins. We propose the L174 M mutation might lead to an abnormal N-terminal and probably C-terminal fragments and malfunction of the protein complex. In conclusion, we found a novel PSEN1 mutation in a large family with clinical and pathological diagnosis of early onset familial Alzheimer disease, which may be relevant for other Hispanic populations.