The Stages Needed in Order to Support the Association of a Genotype with Longevity

<p>While <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.0030125#pgen-0030125-g001" target="_blank">Figure 1</a> demonstrates how to obtain genotypes in genes that are important for the assurance of longevity, the verification of such genotypes requires additional analyses. First, one should seek evidence of a relevant biological phenotype. These may include in vitro and in vivo functional assays that demonstrate appropriate alterations in genes and the determination of plasma or tissue levels of substances that reflect an intermediate phenotype. Second, one should ideally develop lines of evidence demonstrating that a given genotype is protective against common diseases of aging, i.e., that the genotypes also modulate health span. These various steps should help to establish genetic factors contributing to exceptional longevity. As such, they should serve as major clues to the pathogenesis of common diseases of aging, thus providing rational strategies of prevention (see text).</p

Visual Presentation of the Frequency Trends of Favorable Genotypes with Exceptional Longevity

<p>This trend was obtained in ∼400 Ashkenazi Jewish subjects over age 95 and ∼600 subjects between ages 60–95 [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.0030125#pgen-0030125-b076" target="_blank">76</a>,<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.0030125#pgen-0030125-b087" target="_blank">87</a>]. While these genotypes were assessed cross-sectionally in groups between ages ∼60–110, it is important to realize that marked selection occurs during the life course. One also should be aware of the fact that very few subjects achieve centenarian status. Of many polymorphic candidate loci, only subjects homozygous for CETP VV, APOC-3 CC, and ADIPOQ del/del genotypes are markedly and significantly enriched among centenarians (see details in text). To be considered a favorable longevity genotype, a monotonic increase should be observed among age groups. This criterion helps to exclude false-positive associations that occur only in one age group but that do not exhibit trends among sequential age groups. Genotypes with unchanged frequencies among age groups serve as partial controls for genotypic distribution and stratification tests. The analysis of such patterns is useful for the identification of candidate “longevity genes.”</p

Data_Sheet_1_Genetic Insights Into Frailty: Association of 9p21-23 Locus With Frailty.docx

<p>Frailty is a complex aging phenotype associated with increased vulnerability to disability and death. Understanding the biological antecedents of frailty may provide clues to healthy aging. The genome-wide association study hotspot, 9p21-23 region, is a risk locus for a number of age-related complex disorders associated with frailty. Hence, we conducted an association study to examine whether variations in 9p21-23 locus plays a role in the pathogenesis of frailty in 637 community-dwelling Ashkenazi Jewish adults aged 65 and older enrolled in the LonGenity study. The strongest association with frailty (adjusted for age and gender) was found with the SNP rs518054 (odds ratio: 1.635, 95% CI = 1.241–2.154; p-value: 4.81 × 10⁻⁰⁴) intergenic and located between LOC105375977 and C9orf146. The prevalence of four SNPs (rs1324192, rs7019262, rs518054, and rs571221) risk alleles haplotype in this region was significantly higher (compared with other haplotypes) in frail older adults compared with non-frail older adults (29.7 vs. 20.8%, p = 0.0005, respectively). Functional analyses using in silico approaches placed rs518054 in the CTCF binding site as well as DNase hypersensitive region. Furthermore, rs518054 was found to be in an enhancer site of NFIB gene located downstream. NFIB is a transcription factor that promotes cell differentiation during development, has antiapoptotic effect, maintains stem cell populations in adult tissues, and also acts as epigenetic regulators. Our study found novel association of SNPs in the regulatory region in the 9p21-23 region with the frailty phenotype; signifying the importance of this locus in aging.</p

Haplogroup frequencies among AJ from various origins.

<p>Ru = Russians Uk = Ukrainians.</p>*<p>AJs from other maternal geographic origins have been omitted from this table.</p

Haplogroup frequencies among AJ centenarians and controls.

<p>Haplogroup frequencies among AJ centenarians and controls.</p

Survival Analysis according to <i>APOC3</i> Genotypes

<div><p>Of the 381 participants we genotyped since 1998, 64 had the −641 CC genotype. To describe the relationship between genotype and death, we plotted the Kaplan–Meier survival function estimates of probands and controls by <i>APOC3</i> genotype. Offspring were excluded in this analysis because all participants are currently alive and offspring genotype/phenotype is not independent of the probands. </p> <p>Log-Rank ( <i>p</i> = 0.0008); Wilcoxon ( <i>p</i> = 0.0007). </p> <p>CC, homozygous for (−641) C; CA/AA, homozygous and heterozygous for (−641) A.</p></div

Genotype Distribution of <i>APOC3</i> C(−641)A and Serum APOC3 Concentrations

<div><p>(A) <i>APOC3</i> C(−641)A. </p> <p>(B) Serum APOC3.</p> <p>* <i>p</i> < 0.05, ** <i>p</i> = 0.001 versus control. </p> <p>CC, homozygous for (−641) C; AA, homozygous for (−641) A; CA, heterozygous for (−641) C/A.</p></div

Distribution of “Favorable” Gene Polymorphisms of <i>APOC3, APOA4,</i> and <i>CETP</i> in the Study Population

<p>The genotype frequencies of the favorable gene polymorphisms of <i>APOC3 C(</i>− <i>641)A</i> and <i>CETP</i> I405V were analyzed in controls and probands (60 to 100 y old). (Offspring were not included in this analysis due to the genotype dependency of this group on proband genotypes.) The frequency of these two variants was found to be higher among centenarians, with a monotonic increase with age. Other polymorphisms in these same genes ( <i>APOC3</i> (−455) TT, <i>APOA4</i> 347 TT, and <i>APOA4</i> 360 EE) showed no differences in genotype frequency with age. </p

Haplotype Structure of <i>APOC3</i> and <i>APOA4</i> and <i>CETP</i>

<div><p>Ordinal arrangement of 15 SNP associated with CVD and lipoprotein metabolism, according to their position on chromosomes with LD (number in boxes) where the highest rate is represented in red and no LD in lilac. Blocks define potential haplotypes between two clustered genes.</p> <p>(A) <i>APOC3</i> and <i>APOA4.</i></p> <p>(B) <i>CETP.</i></p></div

Case and Control Genotype Frequencies.

(1)<p>The ‘risk’ allele for the WFS1 SNP is the major allele, C. The risk allele for all other SNPs is the minor allele.</p