Mitochondria and skin disease

In addition to the 3 billion base pair nuclear genome, each human cell cont ains thousands of copies of a small. 16.5 kb circular molecule of double st randed DNA: mitochondria have their own DNA (mtDNA) which generally account s for only 1% of the total cellular nucleic acid content. Therefore why sho uld anyone, particularly in the field of dermatology, have an interest in t his cytoplasmic organelle and its DNA? This review will address this questi on; there are three principle reasons: (i) mitochondria have a crucial role both in energy production and the viability of the cell and recently mitoc hondria have been implicated in programmed cell death (apoptosis), Although much smaller than the nuclear genome, mtDNA is equally important. MtDNA de fects and the resulting mitochondrial dysfunction is an important contribut or to human degenerative diseases. ageing and cancer; (ii) mtDNA is a signi ficant target of ultraviolet radiation and current work shows that it may b e useful as a candidate biomarker of cumulative exposure in skin: and (iii) there is a broad spectrum of skin manifestations that are signs of mitocho ndrial disorders; in addition, the frequency of skin findings in these synd romes is probably under-reported.