SALL1 and Townes-Brocks syndrome: Heterozygous Sall1ΔZn2-10 mice, expressing early truncated Sall1, resemble the classical TBS phenotype and homozygous Sall1ΔZn2-10 mice are embryonically lethal and present with a severe TBS phenotype with CNS involvement.6,14 The phenotype in p.R1054* homozygotes resembles the phenotype of homozygous Sall1ΔZn2-10 mice.