Pedigrees of families with a high frequency of HL. Pedigree representation of the 36 families included for analysis. Variants listed segregate with the disease phenotype and obligate carriers within each pedigree. HL16594: TCF3-p.E496K and HBS1L-p.I388V demonstrate potential codominant inheritance; HL213: RAD51D-p.G192D; HL533: ARMC9-p.K423Rfs∗29; HL696: TRPG1-p.Y61∗; HL2350: KDR-p.A1065T; HL2408: POLR1E-p. R149∗ and CDT1-c.1477+3_1477+24del† (limited support of alternative allele for father of proband); HL2491: KLHDC8B-c.-1108C>T and GATA3-intronic; HL2576: no variant; HL2696: EFR3B-p.Q285∗; HL2694: EEF2KMT-p.K177∗; HL3056: no variant; HL3262: KDR-p.A1065T, DDX10-p.K687∗, EIF1AD-c.88-4C>G; HL4479: BAD-p.K133Q, CLEC16A-p.R860C; HL3402: IRF7-p.W238∗; HL4450: KLHDC8B-c.1108C>T; HL4643: IRF8-intronic; HL3929: POT1-p.D224N and GATA3-intronic; HL4897: no variant; HL4968: no variant; HL5140: no variant; HL5171: MAP3K7-p.V428I and MET-p.P791L; HL5215: no variant; HL6898: PAX5-intronic(3)∗; HL1000001: MST1R-p.V233Cfs∗16; HL1000003: PAX5-intronic(3)∗; HL1000007: BLK-c.369-2A>G and GPNMB-c.367+2T>C; HL1000008: no variant; HL1000056: REL-p.H307R; HL1000059: GSN-p.W554∗ and IGSF10-p.S1099∗; HL1000060: ACOT8-c.488+1G>A, CARD9-c.184+1G>A, MROH2A-c.4452+1G>A, and ZNF683-p.R35∗; HL1000061: no variant; HL1000063: KLHDC8B-c.1108C>T; HL1000064: KDR-c.3849-2A>C and RUNX3-intergenic; HL1000065: ATF3-intronic and MYB-intergenic; and HL1000078: JUNB-p.P112S and POLR1E-p.L283Sfs∗9. WT, wild-type.