Overview on visceral manifestations of mitochondrial disorders.

Mitochondriopathies (MCPs) that reach adult age not only manifest in the central and peripheral nervous systems, eyes, ears, and dermis, but also in visceral organs, such as endocrine organs, heart, liver, guts, kidneys and blood. Visceral manifestations occur as part of a multisystem involvement or rarely as single organ affection. Endocrinological abnormalities are found in the MELAS, MERRF , KSS , MID and DID MOAD syndromes. Cardiac involvement occurs in the MELAS, MERRF , KSS , CPEO, LHO N, NARP, and Leigh syndromes. Gastrointestinal manifestations are common in the MERRF , MNGI E, DID MOAD, and Leigh syndromes. Mitochondrial syndromes with renal manifestations are the KSS , Pearson, DID MOAD, and Leigh syndromes. The haematopoetic system is affected in the KSS , MERRF , and Leigh syndromes. In addition, visceral manifestations are found in many nonsyndromic MCPs. Although there is no causal therapy for MCPs, adequate symptomatic therapy, particularly of visceral manifestations, markedly improves quality of life and prognosis of these still often neglected or overlooked disorders.