Figure 5.

Carriers of RTEL1 rare variants have short telomeres and increased T-circle formation. (A) Telomere restriction fragment (TRF) is plotted versus age for probands from families in the familial interstitial pneumonia (FIP) registry. All probands in RTEL1-mutation families were less than or equal to 10th percentile for age, similar to what is seen for TERT (n = 18), TERC (n = 2), and DKC1 (n = 1). (B) A 1-D electrophoresis gel from T-circle assay comparing age-matched unaffected married-in control subjects, TERT mutation carriers, and RTEL1 mutation carriers. (C) Quantification of T-circle formation in peripheral blood mononuclear cells, defined as the percentage of T-circles compared with total telomeric DNA in eight unaffected control subjects, nine TERT mutation carriers, and 20 RTEL1 mutation carriers. *P < 0.001 across groups and pairwise RTEL1 carrier versus control and RTEL1 carriers versus TERT carriers.