Squamous Cell Carcinoma
Table 3. Genes Associated with Fanconi Anemia (FA)
|Gene||Locus||Approximate Incidence Among FA Patients (%)||Pattern of Disease Transmission|
|AR = autosomal recessive; XLR =X-linked recessive.|
The proteins involved with DNA crosslink repairs have been termed the FANC pathway because of their involvement with Fanconi anemia. They interact with several other proteins associated with hereditary cancer risk, including those for Bloom syndrome and ataxia-telangiectasia. Further investigation has revealed that FANCD1 is the same gene as BRCA2, a gene that causes predisposition to breast and ovarian cancer. Other Fanconi anemia genes, FANCJ (BRIP1) and FANCN (PALB2), have also been identified as rare breast cancer susceptibility genes. (Refer to the PDQ summary on Genetics of Breast and Ovarian Cancer for more information about BRCA2, BRIP1, and PALB2.) Individuals who are heterozygous carriers of other Fanconi anemia–associated mutations do not appear to have an increased risk of cancer, with the possible exception of a twofold increase in breast cancer incidence in FANCC mutation carriers.
Dyskeratosis congenita (Zinsser-Cole-Engman syndrome)
Dyskeratosis congenita, like Werner syndrome, results in premature aging and is considered a progeroid disease. The classic clinical triad for diagnosis includes dysplastic nails, reticular pigmentation of the chest and neck, and oral leukoplakia. In addition, individuals with this disorder are at markedly increased risk of myelodysplastic syndrome, acute leukemia, and bone marrow failure. Ocular, dental, neurologic, gastrointestinal, pulmonary, and skeletal abnormalities have also been described in conjunction with this disease, but clinical expressivity is variable. Developmental delay may also be present in variants of dyskeratosis congenita, such as Hoyeraal Hreidarsson syndrome and Revesz syndrome.