Old Order Amish Analysis Highlights Autozygosity, Potential Ties to Blood Measures

For a paper appearing in BMC Genomics, a team from the University of Maryland School of Medicine, Baltimore Veterans Administration Medical Center Geriatrics Research and Education Clinical Center, and the Regeneron Genetics Center explore potential ties between dozens of complex cardiometabolic traits and autozygosity in more than 7,200 Old Order Amish individuals from Pennsylvania's Lancaster County. Using array-based genotyping data for 7,221 Old Order Amish participants, the researchers unearthed more than 17 runs-of-homozygosity larger than 1,500 bases per person, on average, along with average ROH lengths reaching nearly 6,400 bases. Although ROH events stemming from identity-by-descent did not show genome-wide associations to the 96 complex traits considered, the authors did see regional association between autozygosity levels on chromosomes 2 and 8 that coincided with two blood measures: serum bilirubin and glycated hemoglobin (HbA1c) levels, respectively. These and other findings "highlight the potential value of autozygosity mapping in founder populations," they suggest, noting that "[A]mish have larger ROH segments and more of the Amish genome included in autozygous regions compared to outbred populations."