Dyskeratosis congenita (DC) is a multi-system disorder which in its classical 
form is characterised by abnormalities of the skin, nails and mucous membranes. 
In approximately 80% of cases, it is associated with bone marrow dysfunction. A 
variety of other abnormalities (including bone, brain, cancer, dental, eye, 
gastrointestinal, immunological and lung) have also been reported. Although 
first described almost a century ago it is the last 10 years, following the 
identification of the first DC gene (DKC1) in 1998, in which there has been 
rapid progress in its understanding. Six genes have been identified, defects in 
which cause different genetic subtypes (X-linked recessive, autosomal dominant, 
autosomal recessive) of DC. The products of these genes encode components that 
are critical for telomere maintenance; either because they are core constituents 
of telomerase (dyskerin, TERC, TERT, NOP10 and NHP2) or are part of the 
shelterin complex that protects the telomeric end (TIN2). These advances have 
also highlighted the connection between the more "cryptic/atypical" forms of the 
disease including aplastic anaemia and idiopathic pulmonary fibrosis. Equally, 
studies on this disease have demonstrated the critical importance of telomeres 
in human cells (including stem cells) and the severe consequences of their 
dysfunction. In this context DC and related diseases can now be regarded as 
disorders of "telomere and stem cell dysfunction".