Whereas some

of these values will be determined upon first blood donation only, others will be measured repeatedly in appropriate HSP signaling pathway time frames in order to phenotype “physiological” stress resulting from repeated blood donations over time. Detection of genetic donor polymorphism will focus on SNPs. Focusing in on “tagSNPS”, which are representative for haplotypic blocks of genes, allows the identification of genetic variation without genotyping every SNP in a chromosomal region [102] and [103]. However, dependent on the number of haplotype blocks per gene, which is roughly influenced by its length in base pairs, single SNPs up to several SNPs of potential influence on iron metabolism may be identified for every single gene involved [62] and [101]. This enlarged candidate gene approach is in contrast to GWAS, which scans the entire genome for common genetic variation. The rationale behind specifically focusing on allelic variation, is that this approach is better suited for detecting genes underlying common and BYL719 concentration more complex diseases where the risk associated with any given candidate gene is relatively small [104], [105] and [106]. This approach usually uses the case–control study design. Switching to numbers, a reasonable

study protocol for a “global” approach to iron metabolism may involve 20 to 30 genes with an average of 5–10 SNPs per gene as detailed earlier, and may collect pheno- and genotype data of some 12,000–18,000 well selected blood donors considering the cohorts’ sex ratio, these and percentages of pre-/postmenopausal women, first time donors, and depleting and nondepleting long term donors [62] and [101].

This means, that with respect to the genetic analysis alone, 1.2 to 5.4 million SNPs would await their detection. Technically, several platforms allow for such projects, of which only matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry (MALDI-TOF MS) will be discussed here. MALDI-TOF MS was initially introduced in proteomics applications, while the full potential for DNA analysis was demonstrated in 1995 [107]. Optimized for the detection of nucleic acids the MALDI-TOF MS (MassARRAY, Sequenom, San Diego, USA) system is currently applied for SNP genotyping (including insertions and deletions), somatic mutation screening, quantitative gene expression and copy number variation analysis, and DNA methylation detection [108], [109], [110], [111] and [112]. The platform supports multiplexed reactions up to a plex level of 40 + assays (SNPs) per reaction, acquires and interprets data quickly, gives a quantitative output and is highly sensitive [113]. MALDI-TOF MS SNP genotyping is accurate, highly automatable and fast, with a capacity of up to 150,000 SNPs per day [113] and [114]. Currently, data interpretation seems to be biggest task for the “global” genomic approach of iron metabolism.