Positive Association of the Cathepsin D Ala224Val Gene Polymorphism With the Risk of Alzheimer's Disease.
BACKGROUND
Alzheimer's disease (AD) is the most common cause of senile dementia. In Ecuador, the number of deaths caused by AD increases each year. Epidemiologically, the Ecuadorian population is composed of a mixture of several genetic backgrounds along with environmental factors, that make it unique and ideal for population studies. The main objective of this study was to determine the prevalence of Cystatin C (CST3), Cathepsin D (CTSD) and Manganese superoxide dismutase (MnSOD) amino acid-altering polymorphisms and their influence on the development of AD in the Ecuadorian population.


METHODS
This is a case-control study consisting of 56 patients with AD, from the Department of Neurology at Carlos Andrade Marín Hospital. The control group (n = 55) comprised healthy elderly adults. The inclusion period was from January to August of 2012. Peripheral blood was collected from both groups for DNA extraction, polymerase chain reaction and capillary sequencing.


RESULTS
There was a positive association between a CTSD polymorphism (Ala224Val) and the development of AD (odds ratio = 8.1, 95% confidence interval: 0.9-85.7; P < 0.025). However, the 3 other polymorphisms investigated did not show significant associations with AD.


CONCLUSIONS
Variations in CTSD and MnSOD showed no association with the development of AD, whereas the presence of the Ala224Val polymorphism in CTSD had a positive association with the development of AD.
Instituto de Investigaciones Biomédicas (CAP, JMG-C, AL-C, CS, PEL), Facultad de Ciencias de la Salud, Universidad de las Américas, Quito, Ecuador; Carrera de Ingeniería en Biotecnología, Facultad de Ciencias de la Vida, Escuela Politécnica del Ejército, Sangolquí, Ecuador; and Servicio de Neurología (MS), "Hospital Carlos Andrade Marín," Quito, Ecuador.
César A
CA
Paz-Y-Miño
Jennyfer M
JM
García-Cárdenas
Andrés
A
López-Cortés
Carolina
C
Salazar
Marcos
M
Serrano
Paola E
PE
Leone
D000368:Aged; D000409:Alanine / Q000235:genetics*; D000483:Alleles; D000544:Alzheimer Disease / Q000235:genetics*; D016022:Case-Control Studies; D002402:Cathepsin D / Q000235:genetics*; D055316:Cystatin C / Q000235:genetics; D004484:Ecuador; D005260:Female; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D012307:Risk Factors; D014633:Valine / Q000235:genetics*
D055316:Cystatin C; D002402:Cathepsin D; D014633:Valine; D000409:Alanine