PTPN11 and Pfeiffer syndrome: Among the Tier 1 variants are five mutations previously associated experimentally with selfish selection: FGFR2 c.755C > G (p.Ser252Trp – Apert syndrome), c.758C > G (p.Pro253Arg – Apert syndrome) and c.870G > T (p.Trp290Cys – Pfeiffer syndrome), KRAS c.182A > G (p.Gln61Arg – oncogenic), and PTPN11 c.215C > T (p.Ala72Val – oncogenic) (Table 1).