chapter  13
10 Pages

Oral mucosa

Figure 13.3 ● Hyperkeratosis and hyperhidrosis of palms and soles (72%) (Figure 13.6) ● Bullae are visible especially during childhood and adolescence or in sun-exposed areas

(78%) ● Nail dystrophy (98%); longitudinal ridges, thinning (Figure 13.5)

Figure 13.6 ● Thin, lusterless sparse hair (51%) ● Leukokeratosis of oral mucosa (87%) (Figures 13.7 and 13.8) and less frequently of

pharynx, anorectal and urogenital mucosae

Extracutaneous manifestations ● Epiphora, i.e. persistent overflow of tears due to obstruction of lachrymal ducts (78%):

blepharitis, conjunctivitis ● Early dental loss (63%) or extensive caries ● Aplastic anemia (50%) with bleeding problems and purpura ● Esophageal diverticuli with dysphagia (59%) ● Retardation of growth (50%) ● Hypogonadism (40%) ● Mental retardation (42%) ● Macular amyloidosis

Course and complications

There is a poor prognosis. Death is the rule, often in the third decade

● Malignant neoplasms, most often squamous cell carcinomas of mucosal surfaces

● Irreversible condition with high mortality owing to failure of bone marrow,

hematologic malignancies (mainly in the second or third decade)

Laboratory investigations

● Blood count ● Bone marrow biopsy ● Accurate study of cellular immunity ● X-ray of bones ● Histopathological findings:

– skin: thinned epidermis, vacuolar alterations, sparse perivascular lymphocytic infiltrate

– mucous membranes: atypical keratinocytes with thickened ortho-and parakeratotic epithelium

Genetics and pathogenesis

Mutations in the gene called DKC1 encoding a modulator of the telomerase RNA and for ribosomal RNA processing (X-linked form) and in the gene called hTERC (RNA telomerase) (autosomal dominant form) are strictly related to the symptoms (premature aging, anemia and bone marrow malignancies and neoplastic proneness) of dyskeratosis congenita.