Limited diagnostic value of enzyme analysis in patients with mitochondrial tRNA mutations

Flemming Wibrand; Tina Dysgaard Jeppesen; Anja L Frederiksen; David Holkmann Olsen; Morten Dunø; Marianne Schwartz; John Vissing

doi:10.1002/mus.21541

Limited diagnostic value of enzyme analysis in patients with mitochondrial tRNA mutations

Flemming Wibrand, Tina Dysgaard Jeppesen, Anja L Frederiksen, David Holkmann Olsen, Morten Dunø, Marianne Schwartz, John Vissing

15 Citations (Scopus)

Abstract

We evaluated the diagnostic value of respiratory chain (RC) enzyme analysis of muscle in adult patients with mitochondrial myopathy (MM). RC enzyme activity was measured in muscle biopsies from 39 patients who carry either the 3243A>G mutation, other tRNA point mutations, or single, large-scale deletions of mtDNA. Findings were compared with those obtained from asymptomatic relatives with the 3243A>G mutation, myotonic dystrophy patients, and healthy subjects. Plasma lactate concentration, maximal oxygen uptake, and ragged-red fibers/cytochrome c-negative fibers in muscle were also determined. Only 10% of patients with the 3243A>G point mutation had decreased enzyme activity of one or more RC complexes, whereas this was the case for 83% of patients with other point mutations and 62% of patients with deletions. Abnormal muscle histochemistry was found in 65%, 100%, and 85% of patients, respectively, in these three groups. The results indicate that RC enzyme analysis in muscle is not a sensitive test for MM in adults. In these patients, abnormal muscle histochemistry appears to be a better predictor ofMM.

Original language	English
Journal	Muscle & Nerve
Volume	41
Issue number	5
Pages (from-to)	607-13
Number of pages	7
ISSN	0148-639X
DOIs	https://doi.org/10.1002/mus.21541
Publication status	Published - 1 May 2010

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title = "Limited diagnostic value of enzyme analysis in patients with mitochondrial tRNA mutations",

abstract = "We evaluated the diagnostic value of respiratory chain (RC) enzyme analysis of muscle in adult patients with mitochondrial myopathy (MM). RC enzyme activity was measured in muscle biopsies from 39 patients who carry either the 3243A>G mutation, other tRNA point mutations, or single, large-scale deletions of mtDNA. Findings were compared with those obtained from asymptomatic relatives with the 3243A>G mutation, myotonic dystrophy patients, and healthy subjects. Plasma lactate concentration, maximal oxygen uptake, and ragged-red fibers/cytochrome c-negative fibers in muscle were also determined. Only 10% of patients with the 3243A>G point mutation had decreased enzyme activity of one or more RC complexes, whereas this was the case for 83% of patients with other point mutations and 62% of patients with deletions. Abnormal muscle histochemistry was found in 65%, 100%, and 85% of patients, respectively, in these three groups. The results indicate that RC enzyme analysis in muscle is not a sensitive test for MM in adults. In these patients, abnormal muscle histochemistry appears to be a better predictor ofMM.",

author = "Flemming Wibrand and Jeppesen, {Tina Dysgaard} and Frederiksen, {Anja L} and Olsen, {David Holkmann} and Morten Dun{\o} and Marianne Schwartz and John Vissing",

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doi = "10.1002/mus.21541",

language = "English",

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T1 - Limited diagnostic value of enzyme analysis in patients with mitochondrial tRNA mutations

AU - Wibrand, Flemming

AU - Jeppesen, Tina Dysgaard

AU - Frederiksen, Anja L

AU - Olsen, David Holkmann

AU - Dunø, Morten

AU - Schwartz, Marianne

AU - Vissing, John

PY - 2010/5/1

Y1 - 2010/5/1

N2 - We evaluated the diagnostic value of respiratory chain (RC) enzyme analysis of muscle in adult patients with mitochondrial myopathy (MM). RC enzyme activity was measured in muscle biopsies from 39 patients who carry either the 3243A>G mutation, other tRNA point mutations, or single, large-scale deletions of mtDNA. Findings were compared with those obtained from asymptomatic relatives with the 3243A>G mutation, myotonic dystrophy patients, and healthy subjects. Plasma lactate concentration, maximal oxygen uptake, and ragged-red fibers/cytochrome c-negative fibers in muscle were also determined. Only 10% of patients with the 3243A>G point mutation had decreased enzyme activity of one or more RC complexes, whereas this was the case for 83% of patients with other point mutations and 62% of patients with deletions. Abnormal muscle histochemistry was found in 65%, 100%, and 85% of patients, respectively, in these three groups. The results indicate that RC enzyme analysis in muscle is not a sensitive test for MM in adults. In these patients, abnormal muscle histochemistry appears to be a better predictor ofMM.

AB - We evaluated the diagnostic value of respiratory chain (RC) enzyme analysis of muscle in adult patients with mitochondrial myopathy (MM). RC enzyme activity was measured in muscle biopsies from 39 patients who carry either the 3243A>G mutation, other tRNA point mutations, or single, large-scale deletions of mtDNA. Findings were compared with those obtained from asymptomatic relatives with the 3243A>G mutation, myotonic dystrophy patients, and healthy subjects. Plasma lactate concentration, maximal oxygen uptake, and ragged-red fibers/cytochrome c-negative fibers in muscle were also determined. Only 10% of patients with the 3243A>G point mutation had decreased enzyme activity of one or more RC complexes, whereas this was the case for 83% of patients with other point mutations and 62% of patients with deletions. Abnormal muscle histochemistry was found in 65%, 100%, and 85% of patients, respectively, in these three groups. The results indicate that RC enzyme analysis in muscle is not a sensitive test for MM in adults. In these patients, abnormal muscle histochemistry appears to be a better predictor ofMM.

U2 - 10.1002/mus.21541

DO - 10.1002/mus.21541

M3 - Journal article

SN - 0148-639X

VL - 41

SP - 607

EP - 613

JO - Muscle & Nerve

JF - Muscle & Nerve

IS - 5

ER -

Limited diagnostic value of enzyme analysis in patients with mitochondrial tRNA mutations

Abstract

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