title: A prognostic index as diagnostic strategy in children suspected of mitochondriocytopathy.
abstract: The aim of this study was to assess an optimal screening for paediatric patients suspected of mitochondriocytopathy to justify a muscle biopsy. Forty-five patients were included. Medical history, physical examination, cardiac and ophthalmologic evaluation, clinical chemical investigations, in vivo function tests, neuroimaging and a skeletal muscle biopsy were performed in all patients. The results of the biochemical muscle studies were compared with the results of the other investigations. First, parameters with a statistical relationship with the result in muscle, normal or deficient, were selected. Secondly, a prognostic index was constructed using these parameters. Five parameters were selected: age <4 years, elevated fasting lactate to pyruvate ratio, elevated thrombocyte count, elevated lactate, and elevated alanine. Each parameter was scored 0 (not present) or 1 (present). The chance of a normal biopsy with a given value of this index (sum of the scores) was calculated: logit (Pr) = alpha + beta x index; alpha: -0.8167 and beta: 0.8331. (Pr: probability of normal biopsy.) The chance of a normal biopsy with an index value of 5 is 0.03, 4 is 0.07, 3 is 0.16, 2 is 0.30, 1 is 0.50 and 0 is 0.69. This prognostic index is a valuable instrument in deciding whether the suspicion of mitochondriocytopathy is strong enough to merit a muscle biopsy.
authors.affiliation: Department of Metabolic Diseases, University Hospital Nijmegen, The Netherlands. E.Rubio@ckskg.azn.nl
authors.forename: M E
authors.initials: ME
authors.lastname: Rubio-Gozalbo
authors.forename: R C
authors.initials: RC
authors.lastname: Sengers
authors.forename: J M
authors.initials: JM
authors.lastname: Trijbels
authors.forename: W H
authors.initials: WH
authors.lastname: Doesburg
authors.forename: A J
authors.initials: AJ
authors.lastname: Janssen
authors.forename: A L
authors.initials: AL
authors.lastname: Verbeek
authors.forename: J A
authors.initials: JA
authors.lastname: Smeitink
mesh_terms: D000293:Adolescent; D000328:Adult; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D004272:DNA, Mitochondrial / Q000235:genetics; D004579:Electron Transport / Q000502:physiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D019344:Lactic Acid / Q000097:blood; D017241:MELAS Syndrome / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics; D008297:Male; D000226:Mitochondrial ADP, ATP Translocases / Q000378:metabolism; D018482:Muscle, Skeletal / Q000201:enzymology / Q000473:pathology*; D018384:Oxidative Stress; D010766:Phosphorylation; D011379:Prognosis; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism; D012016:Reference Values; D012720:Severity of Illness Index
chemical_list: D004272:DNA, Mitochondrial; D011768:Pyruvate Dehydrogenase Complex; D019344:Lactic Acid; D000226:Mitochondrial ADP, ATP Translocases