HLA risk alleles predispose to clonal expansion over time. Shown are the longitudinal analyses of frequencies of somatic alterations in patients with (A) and without (B) risk alleles. Clone size was estimated as percentage immunophenotypic PNH granulocytes for PNH, percentage abnormal metaphases for chromosomal abnormalities, percentage abnormal cells from SNP-A for 6p CN-LOH, and 2 × percentage NGS mutant reads for somatic mutations (to account for diploid status).