(A) Sanger sequencing confirmed a heterozygous 2 base pair deletion on chromosome 1:95,001,582 GCT>G. A red vertical arrow indicates the start of the deletion, after which competing sequences reflect the frameshift. (B) The frameshift encodes TF p.Ser117HisfsTer10. A schematic of the TF protein highlights features of the primary structure and domain organization. The mutation at position 117 is indicated by the vertical red arrow. SP, signal peptide; TM, transmembrane segment.