The nematode genome encodes three orthologues for PSEN1
: (i) sel-12, (ii) hop-1, and (iii) spe-4.
The researchers generated induced pluripotent stem (iPS) cells from affected and unaffected individuals from two families carrying PSEN1
Ringman reported that 159 were at risk for PSEN1
mutations, 19 for PSEN2 mutations, and 34 for APP mutations.
Mutations in three dominant genes (PSEN1
, PSEN2 and APP) were shown to account for increased risk in early-onset AD (Levy-Lahad, Lahad, Wijsman, Bird, & Schellenberg, 1995; Sherrington et al., 1995; Sleegers & van Duijn, 2001; Tanzi & Bertram, 2001).
Genetic markers associated with autosomal dominant early-onset (typically occurs before the age of 65 years) familial AD include mutations in the amyloid precursor protein (APP) gene and in the genes for presenilin 1 and 2 (PSEN1
and PSEN2), proteins that make up part of the secretase protein complex.
Prevention efforts for Alzheimer's focus on a mutation that affects the gene PSEN1
, which is involved in the production amyloid protein.
A team of scientists from Cardiff University have been examining three genes - APP, PSEN1
and PSEN2 - which are known to cause rare early onset forms of Alzheimer's.
The genetic component is most conspicuous in a relatively small percentage (< 1%) of families that carry disease-causing germline mutations in 1 of 3 genes--APP [amyloid beta (A4) precursor protein], PSEN1
(presenilin 1), or PSEN2 (presenilin 2)--that will invariably lead to AD, often at a relatively young age.
George-Hyslop et al., 1987), the Presenilin I (PSEN1
) gene on chromosome 14 (Mullan et al., 1992; Schellenberg et al., 1992; St.
Quiroz, Ph.D., from Massachusetts General Hospital in Boston, and colleagues assessed measures of carbon 11-labeled Pittsburgh Compound B positron emission tomography (PET) and flortaucipir F18 PET imaging in 24 presenilin 1 (PSEN1
) E280A autosomal dominant AD kindred members including 12 carriers (nine cognitively unimpaired; three with mild cognitive impairment) and 12 cognitively unimpaired noncarriers.
Neurons derived from iPSCs generated from familial AD (fAD) patients carrying mutations in genes encoding amyloid precursor protein (APP), presenilin 1 (PSEN1
), and presenilin 2 (PSEN2) provide an innovative tool to elucidate AD etiology and develop efficient therapeutics.