Children with the condition often have fingernails and toenails that grow poorly or are abnormally shaped. They also often have changes in skin colouring (pigmentation), especially on the neck and chest. White patches inside the mouth (oral leukoplakia) is another well-known characteristic of dyskeratosis congenita.
People with dyskeratosis congenita are especially vulnerable to impairment of bone marrow function (bone marrow failure). As the main function of the bone marrow is to produce new blood cells, affected individuals may develop aplastic anaemia (when the bone marrow does not produce enough new blood cells). They are also at higher than average risk for myelodysplastic syndrome, a condition in which immature blood cells fail to develop normally and which may progress to a form of blood cancer called leukaemia. People with dyskeratosis congenita are also at increased risk of developing leukaemia in the absence of myelodysplastic syndrome. In addition, they have a higher than average risk of developing other cancers, especially cancers of the head, neck, anus or genitals.
People with dyskeratosis congenita may also develop pulmonary fibrosis, a condition that causes scar tissue (fibrosis) to build up in the lungs, decreasing the transport of oxygen into the bloodstream.