RTEL1 and hypotrichosis 1: In patients with HHs, RTEL1 deficiency is associated with pathological pathways, such as the reduced availability of the 3′ end of the telomeres for elongation by telomerase,25 splicing defects, abnormal intracellular trafficking of the small nuclear RNA pre‐U2, and defects in the recycling of ribonucleoproteins in the cytoplasm.26