Variation in the DCP1 gene, encoding the angiotensin converting enzyme ACE, is not associated with increased susceptibility to Alzheimer's disease.
OBJECTIVE
To attempt to replicate previous reports that polymorphic variation in the DCP1 gene causes increased susceptibility to the development of Alzheimer's disease, either on its own or in interaction with the effects of the gene for apolipoprotein E (APOE).


METHODS
Subjects older than 65 years of age consisting of 81 dementia patients diagnosed as having possible or probable Alzheimer's disease and 68 controls were obtained from Camden, Islington and Harlow psychiatric services. Subjects were genotyped for APOE alleles e2, e3 and e4, and the common insertion/deletion polymorphisms for DCP1* I/D were genotyped.


RESULTS
There was no statistically significant difference in the frequency of the DCP1* insertion/deletion alleles between the cases and controls (X2 =0.04, 1 degree of freedom, not significant). When subjects were subdivided according to whether they possessed at least one copy of the APOE e4 allele, there were still no differences in DCP1 allele frequencies between cases and controls.


CONCLUSIONS
Further research is needed to elucidate any role that the DCP1 polymorphism may play in relation to Alzheimer's disease. Previous studies may be false positive, or inconsistency in replication may be due to heterogeneity.
Carbonell
J
J
Molecular Psychiatry Laboratory, Windeyer Institute of Medical Sciences, Department of Psychiatry and Behavioural Sciences, Royal Free and University College Medical School, University College London, London, UK.
Allen
R
R
Kalsi
G
G
McQuillin
A
A
Livingston
G
G
Katona
C
C
Walker
Z
Z
Katz
A
A
Rands
G
G
Stevens
T
T
Crossan
I
I
Curtis
D
D
Gurling
H
H
D000368:Aged; D000544:Alzheimer Disease / Q000201:enzymology / Q000235:genetics*; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics; D004251:DNA Transposable Elements; D004198:Disease Susceptibility; D004722:Endoribonucleases; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics*
D053327:Apolipoprotein E4; D001057:Apolipoproteins E; D004251:DNA Transposable Elements; D015534:Trans-Activators; D004722:Endoribonucleases; C466279:DCP1A protein, human; D007703:Peptidyl-Dipeptidase A