Fig. 1

The components of the telomere. The outermost part of the telomeres is protected by a Shelterin complex consisting of six proteins: TRF1, TRF2, TIN2, POT1, TPP1 and RAP1. The telomeres are maintained at each cell division by a telomerase consisting of telomerase reverse transcriptase (TERT) and an RNA part that acts as a template when the nucleotides must be inserted during replication of the telomeres (TERC and DKC1). In addition, a number of proteins contribute to the maintenance and function of the telomeres. This applies to the CST complex (CTC1, STN1 and TEN1) and RTEL1, TCAB1 and PARN. The inheritance pattern is implicated by coloring. Pink: autosomal recessive inheritance; Yellow: autosomal dominant inheritance; Blue: autosomal recessive and autosomal dominant inheritance; Red: X-linked recessive inheritance. Proteins shown but not yet reported associated with TBD are colored in gray