NEW YORK (GenomeWeb) – The frequencies of risky and protective versions of the Alzheimer's disease- and cognitive decline-related gene APOE appears to vary significantly from one Latino population to the next, according to new study from a team led by researchers at the University of Texas Health Science Center and the University of California, San Diego.
"These data provide valuable information in this understudied ethnic group and provide the basis for future studies of the association of APOE with [Alzheimer's disease and related dementias (ADRD)] in this fast-growing segment of the US population," senior and corresponding author Myriam Fornage, a molecular medicine and human genetics researcher affiliated with the University of Texas Health Science Center, and her colleagues wrote.
As they reported online today in Scientific Reports, the researchers used a custom array to genotype APOE in nearly 10,900 individuals with diverse Latino ancestry from four metropolitan areas in the US — the Bronx, Chicago, Miami, and San Diego. These individuals are participating in the Hispanic Community Health Study/Study of Latinos in an effort to better understand APOE allele patterns and risk for ADRD in these populations.
"Given its broad impact on health and disease, it is important to characterize the distribution of this significant genetic risk and possible protective factor among diverse and understudied populations, including Hispanics/Latinos," the authors explained, noting that Latino individuals appear more prone to developing Alzheimer's disease or ADRD than Caucasian individuals.
The genotyped participants included representatives from Central American, Cuban, Dominican, Mexican, Puerto Rican, and South American populations, the researchers explained, and had an average age of just over 41 years.
The team found that Dominican, Puerto Rican, and Cuban individuals tended to have higher frequencies of the well-known ADRD and cognitive decline risk allele APOE4. That risky APOE4 allele was found at almost 18 percent frequency in Dominicans, while Cubans and Puerto Ricans carried the allele at intermediate frequency. However, it appeared to be far less common in individual from mainland populations in Mexico, Central America, and South America, which had APOE4 allele frequencies of around 11 percent.
On the other hand, the researchers found that the APOE2 allele, which has been proposed as a protective factor against cognitive decline and ADRD, was found at enhanced frequencies in individuals from Caribbean Latino populations, dipping in individuals from Central America, and turning up at the lowest frequencies in the South American and Mexican populations.
The APOE3 allele, the most common version of APOE across human populations profiled so far, was found in more than 86 percent of Mexicans and in almost 74 percent of Dominicans, the team reported.
The latest findings and other data published previously "underscore the need for large studies of diverse Latinos with well-characterized ethnic backgrounds to better understand the nature of the association between AD and the APOE genotypes in the fastest-growing segment of the US population," the authors wrote.