The premature ageing syndromes: insights into the ageing process.

Ageing in man results from a complex interaction of genetic and environmental factors. Many overlapping and sometimes conflicting theories of ageing exist and the emergence of a unified theory still seems unlikely. Experimental studies of senescence are difficult to design because of the variable effect of diseases and other extrinsic factors. The syndromes of accelerated ageing have been proposed as models to simplify the analysis of the ageing process, by restricting the focus to a more definable area [1]. Research in this field may give an insight into the nature of the genes that play a role in ageing and help to separate the boundary between ageing and age-related disease. Furthermore, the association of various cancers and vascular pathologies in many of these conditions has allowed a better understanding of the genetic or intrinsic components of these important causes of premature death. Several rare conditions exist in man that exhibit certain phenotypic characteristics associated with senescence. Often referred to as 'segmental progeroid syndromes'[2], the most widely studied of these are Hutchinson-Gilford progeria, Werner's syndrome and Cockayne's syndrome, but the group also includes Bloom's syndrome, ataxia telangiectasia and Down's syndrome. Studies of these syndromes have focused on genetic and cytochemical analysis as well as descriptive approaches to tissue and organ changes. Recent identification of the gene responsible for Werner's syndrome has attracted widespread interest, and rapid developments in our understanding of the cytochemical basis of these diseases can be expected. Whilst Japan and the USA lead in terms of research output relating to these syndromes, European studies also make an important contribution. A recent Medline search revealed that between 1991 and 1995, the UK was the origin of one in five publications relating to the premature ageing syndromes within Europe. This report is not intended to comprehensively review all aspects of these complex and fascinating conditions but rather to demonstrate the relevance of their study to the ageing process.