Description Dyskeratosis congenita is a disorder that can affect many parts of the body. There are three features that are characteristic of this disorder: fingernails and toenails that grow poorly or are abnormally shaped nail dystrophy ; changes in skin coloring pigmentation , especially on the neck and chest, in a pattern often described as "lacy"; and white patches inside the mouth oral leukoplakia. People with dyskeratosis congenita have an increased risk of developing several life-threatening conditions. They are especially vulnerable to disorders that impair bone marrow function.
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Figure 1. Examples of the dyskeratosis congenita diagnostic triad A. Skin pigmentation Note: Individuals with DC may have none of the above additional findings; the findings may appear or worsen with age. Progressive bone marrow failure BMF. May appear at any age and may be a presenting sign.
Macrocytosis and elevated hemoglobin F levels may be seen. May be the presenting sign. Pulmonary fibrosis. See Familial Pulmonary Fibrosis. Shortened telomere length. Individuals with suspected DC should undergo leukocyte telomere length testing by automated multicolor flow- FISH in the six-cell panel assay. Click here for details on this testing.
In individuals with complex or atypical DC, the six-cell panel may be more informative than the two-panel test of total lymphocytes and granulocytes [ Alter et al ].
For more information about telomeres, see Supplemental Material-Telomeres pdf. Establishing the Diagnosis The diagnosis of DC is established in a proband with identification of a pathogenic variant or variants by molecular genetic testing in one of the genes listed in Table 1A or 1B. Molecular testing approaches can include serial single- gene testing, use of a multigene panel , and more comprehensive genomic testing.
Serial single- gene testing can be considered if clinical findings, laboratory findings, ancestry, or inheritance pattern indicate that mutation of a particular gene is most likely. See Table 1A for information on mode of inheritance and relative frequency of the most common genes associated with this condition.
Targeted analysis for pathogenic variants can be performed first in individuals of Ashkenazi Jewish ancestry for the c. A multigene panel that includes the genes listed in Table 1A and Table 1B , and other genes of interest see Differential Diagnosis may also be considered. Note: 1 The genes included in the panel and the diagnostic sensitivity of the testing used for each gene vary by laboratory and are likely to change over time. For an introduction to multigene panels click here.
More detailed information for clinicians ordering genetic tests can be found here. Such testing may provide or suggest a diagnosis not previously considered e. For an introduction to comprehensive genomic testing click here. More detailed information for clinicians ordering genomic testing can be found here.
See Table 1A for the most common genetic causes i. Table 1A.
Learn how and when to remove this template message DKC can be characterized by cutaneous pigmentation, premature graying, dystrophy of the nails , leukoplakia of the oral mucosa, continuous lacrimation due to atresia of the lacrimal ducts , often thrombocytopenia , anemia , testicular atrophy in the male carriers, and predisposition to cancer. Many of these symptoms are characteristic of geriatrics , and those carrying the more serious forms of the disease often have significantly shortened lifespans. Predisposition to cancer[ edit ] Susceptibility to cancer seems counterintuitive because in many known cancers reactivation of telomerase is actually a required step for malignancy to evolve see telomere. In a disease where telomerase is affected, it does not seem to follow that cancer would be a complication to result. The authors note the paradoxical nature of cancer predisposition in individuals who seem to lack one of the required components for cancer to form. It is thought  that without functional telomerase, chromosomes will likely be attached together at their ends through the non-homologous end joining pathway.
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