Dyskeratosis congenita

• Inherited disorder of mucocutaneous and haemopoietic systems.

• Clinical triad of skin pigmentation, leucoplakia of the mucous membranes, dystrophic nails and, in 50% patients, severe aplastic anaemia develops, usually in the second decade.

• Usually sex-linked inheritance through single gene at Xq28, though 15% autosomal so phenotype dependent on more than 1 gene.

• Other congenital and immunological abnormalities described.

• Chromosome fragility on challenge with DEB or mitomycin C normal— important to distinguish DC from Fanconi's anaemia (see previous page).

• Despite this some evidence of DNA instability; results of BMT for aplastic anaemia in DC patients poor, perhaps because of this.

• Anecdotal reports of good response to haemopoietic growth factors.

Outlook

10% develop cancers before the age of 40—mostly epithelial, but also MDS/AML. Life expectancy depends on development of aplasia or malignancy. 30% survive to middle age.

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