The graph shows telomere length in 24 DC patients at presentation and telomere length of healthy controls. All patients shown have dyskeratosis congenita and a mutation in a known DC gene. Telomere lengths were measured by flow cytometric fluorescence in situ hybridization in peripheral blood mononuclear cells. The 1st, 90th, 25th, 50th, 75th, 90th, 99th percentiles of 243 healthy controls between the ages of 1 day and 94 years are shown.