Of 185 patients with rnyopathy, 22 showed abnormal muscle rnitochondria. In 12 of the 22 patients, all of whom had ocular rnyopathy or the ophthalrnoplegia-plus syndrome, muscle biopsies contained 5%-25% “ragged red” fibers. In 4 patients with a facioscapulohurneral distribution of weakness, ragged red fibers were less numerous (3%-8%). In both groups, routine histology showed almost normal muscle. The remaining 6 patients were clinically heterogeneous, all without ptosis or ophthalrnoplegia. The biopsies of three of these patients showed severely affected muscle. It is possible that mitochondria1 changes in these muscles were nonspecific. Electrornyography indicated or suggested a rnyogenic lesion in 21 of the 22 patients; in 10,the serum creatine kinase was increased. MUSCLE & NERVE
1:413-415
1978
MYOPATHIES WITH ABNORMAL MITOCHONDRIA= A CLINICOPATHOLOGIC CLASS1FICATION ZOFIA KAMIENIECKA, MD, and HENNING SCHYALBRUCH, MD
In a series of 185 patients with myogenic disorders, muscle biopsies from 2 2 patients were found to contain fibers that stained atypically for mitochondrial enzymes. This report will attempt to classify these patients according to clinical symptoms and histopathologic changes. METHODS
After electromyography was performed, biopsies were taken from a skeletal muscle contralateral to a muscle in which electrophysiologic abnormalities had been foundusually the brachial biceps or the vastus medialis muscle. In two patients, biopsies were taken from the levator palpebrae and the rectus internus oculi muscles, respectively. These methods have been d e ~ c r i b e d . ~ RESULTS General Morphology. In all biopsies, Gomori trichrome
stain showed granular, bright red material in some fibers, both below the sarcolemma and between myofibrils (“ragged red” fibers). After staining for mitochondrial enzymes, clumps of diformazan deposits appeared at the same sites. All of these fibers stained weakly for ATPase
From the Institute of Neurophysiology, University of Copenhagen, Denmark Acknowledgments Electrophystologic findings were evaluated by Professor F Buchthal This work was supported by the Danish Medical Research Council Address reprint requests to Dr Karnteniecka at the Institute of Neurophysiology, University of Copenhagen, Denmark 0148-639XlO10510413$00 OO/O 1978 Houghton Miffltn Professional Publishers
Mitochondria1 Myopathies
at pH 9.4 (type 1); the amount of intracellular fat was increased. In 12 of the 22 patients, abnormal mitochondria were demonstrated by electron microscopy. The following structures were observed: intramitochondrial crystalloids; abnormally small or large “giant” mitochondria; and large subsarcolemmal accumulations of mit~chondria.~.~ Classification of Patients According to Clinical Symptoms. Patients were divided into three groups as
follows (table 1). Gro@ 1. Twelve patients had weakness of the external eye muscles, either alone or associated with weakness of skeletal muscles. Because of these ocular symptoms, many patients in this group had been referred with a diagnosis of “myasthenia.” Six of these 12 patients were 65 to 70 years old, and the onset of their symptoms (i.e., ptosis, ophthalmoplegia) was late. It is possible that some of these patients suffered from senile ptosis. Two patients conformed to the description of the ophthalmoplegia-plus or the oculocraniosomatic synd r ~ m eone ; ~ case was familial, and the inheritance seemed to be autosomal dominant. In both, weakness of external ocular and skeletal muscles was associated with retinal degeneration, involvement of pharyngeal muscles, and cardiac conduction block. One patient was short; one had relatives with short stature, was deaf, and had diabetes mellitus. In 10 of the 12 patients, ragged red muscle fibers were the only pathologic change. The incidence of such fibers was higher in this group of patients than in the others. The biopsy from a 70-year-old patient with bilateral ptosis, ophthalmoplegia, and proximal weakness of skeletal muscles showed, in addition,
MUSCLE & NERVE
SeptlOct 1978
413
Table 1. Clinical and laboratory findings in 22 patients with abnormal mitochondria of muscle.
Number of cases Age (years) Duration (years) Family history EMG indicating or suggesting myopathy Elevated creatine kinase (2-4 x upper limit of normal) Incidence of "ragged red" fibers
I
II
Ocular myopathy or ophthalmoplegia plus
Facioscapulohumeral syndrome
Myositis
Limb-girdle
Other
12 27-70 (mean 58) 2-49 (mean 13) 2
4
2
2 18-67 (mean 45) 1-30 (mean 16) 1
2
37-60 (mean 48) 18-45 (mean 30) 4
12
4
5
6
2
2
5%-25%
fibers with nemaline bodies, lobulated fibers, and "ringbinden." Biopsies from the levator palpebrae and rectus internus oculi muscles, both taken from patients with severe bilateral ophthalmoplegia, consisted mainly of connective tissue and fat; in the levator palpebrae muscle, smooth muscle cells also were present. Croup 2. Four patients had a facioscapulohumeral distribution of weakness: three were in the same family and one had a similarly affected sister. All were women. Abnormal staining for mitochondria1 enzymes was the only pathologic change in three patients; in one patient, who had had symptoms for more than 15 years, the incidence of internal nuclei also was increased. Of the four, two patients, one of whom was abnormally short, had mild cerebellar symptoms. The remaining two had ptosis, and one of these patients was also relatively short. Group 3. Six patients were clinically heterogeneous: none had ptosis or ophthalmoplegia. Two patients had a myositis, two showed a limb-girdle type of weakness, one had a distal distribution of weakness, and in one patient the distribution of weakness was asymmetric. The latter patient had, in addition, a chronic encephalopathy and pericarditis as well as endocarditis. In routine histology, three biopsies were normal, one showed a myositis, and two had pronounced myogenic changes. The patients with myogenic changes had a limb-girdle type of muscular weakness: both abnormal mitochondria and nemaline bodies were present. One of these latter patients had, in addition, histologic signs of denervation. EM6 and Serum Enzymes. In 21 of 22 patients, EMG
indicated or suggested a myopathy; at least one of the muscles investigated was affected. The duration of motor unit action potentials was shortened, and the incidence of polyphasic potentials was increased (fig. 1). The
414
Mitochondria1 Myopathies
111 Heterogeneous
3%-13%
3%-8%
0 Of0
-1 0
z 3
F -20
a
E
3
n
I X XX
z
a W
I 2-40
W
ln
z-50
E
0 0 0
0
0 0 0
E
u
Figure I. Decrease in duration of motor unit action potentials and incidence of polyphasic potentials in 22 patients with abnormal muscle mitochondria. Hatched area: 95% confidence limits of normal. X = patients with ocular involvement; 0 = patients with facioscapulohumeral syndrome; 0 = those from the "heterogeneous" group. Modified with permission from Kamieniecka Z: Myopathies with abnormal mitochondria. A clinical, histological, and e/ectrophysio/ogical study. Acta Neurol Scand 555775, 1976.
MUSCLE 8, NERVE
SepUOct 1978
discrepancy between pronounced electrophysiologic changes and normal routine histology was often quite striking. Serum creatine kinase was two to four times the upper limit of normal in 10 of the 22 patients studied. DISCUSSION
The presented material demonstrates that abnormal muscle mitochondria can be found in different clinical conditions affecting other organs as well. This confirms previous observation^',^*^ and suggests that, at least in some patients, general defects of tissue metabolism existed that were not confined to muscle. When many ragged red fibers were present, and when this was the only histopathologic abnormality, clinical symptoms were predominantly ocular. This indicates that the changes in mitochondria are an early and possibly basic abnormality. In patients with long-lasting facioscapulohumeral distribution of weakness, the biopsy appeared almost normal in routine histology. This is at variance with findings in facioscapulohumeral muscular dystrophy and suggests that the patients described in this study cannot be classified as having muscular dystrophy, although the clinical symptoms were similar. The presence of intramitochondrial crystalloids is,
however, nonspecific; such crystalloids have been found in patients with various neuromuscular disorders5 and in the muscles of mice more than three years old (A. Kelly, 1978, personal communication). In some patients with abnormal muscle mitochondria, oxidative phosphorylation was ~ n c o u p l e d Conversely, .~~~ crystalloids have been produced in rat muscle by uncoupling the phosphorylation.’ Of two patients with oculocraniosomatic syndrome, one had similarly affected relatives. In 23 cases collected from the literature and one case of his own, Karpati et alfi found no familial occurrence. One familial case was reported by Tamura et a1.8 Because relatives are often asymptomatic, familial cases might have been overlooked in previous investigations. A family with a facioscapulohumeral distribution of weakness was described by Hudgson et al;4muscle fibers contained mitochondria1 crystalloids in three affected members, and oxidative phosphorylation was loosely c~upled.~ The combination of nemaline bodies and intramitochondrial crystalloids, previously described only by D’Agostino et a12 in one familial case with limb-girdle distribution ofweakness, occurred in 3 of the 22 patients in the present series.
REFERENCES 1. Castaigne P, Lhermitte F, Escourolle R, Chain F, Fardeau M, Hauw JJ, Curet J, Flavigny C: Etude anatomoclinique d’une
observation d’ophthalmoplegia plus avec analyse des lesions musculaires, nerveuse centrales, oculaires, myocardiques et thyroidiennes. Rev Neurol (Paris) 133:369-386, 1977. 2. D’Agostino AN, Ziter FA, Rallison ML, Bray PF: Familial myopathy with abnormal muscle mitochondria. Arch Neurol 18:388-401, 1968. 3 . DiMauro S, Schotland DL, Bonilla E, Lee CP, Dimauro PMM, Scarpa A: Mitochondrial myopathies: which and how many? I n Milhorat AT (Editor): Exploratoly Concepts in Muscular Dystrophy, Vol 2 . Amsterdam, Excerpta Medica, 1974, p p 506-515. 4. Hudgson P, Bradley WG, Jenkison M: Familial “mitochondrial” myopathy. A myopathy associated with disordered oxidative metabolism in muscle fibres. Part 1. Clinical, electrophysiological and pathological findings. J Neurol Sci 16: 343-370. 1972.
Mitochondrial Myopathies
5. Karnieniecka Z: Myopathies with abnormal mitochondria. A clinical, histological, and electrophysiological study. Acta Neurol Scand 55:57-75, 1976. 6 . Karpati G, Carpenter S, Larbrisseau A, Lafontaine R: The Kearns-Shy syndrome. A multisystem disease with mitochondrial abnormality demonstrated in skeletal muscle and skin. J Neurol Sci 19:133-151, 1973. 7. Melmed C, Karpati G, Carpenter S: Experimental mitochondrial myopathy produced by in uivo uncoupling of oxidative phosphorylation.] Neurol Sci 26:305-318, 1975. 8. Tamura K, Santa T, Kuroiwa Y: Familial oculocranioskeletal neuromuscular disease with abnormal muscle mitochondria. Bruin 97:665-672, 1974. 9. Worsfold M, Park DC, Pennington RJ: Familial “mitochondrial” myopathy. A myopathy associated with disordered oxidative metabolism in muscle fibres. Part 2. Biochemical findings.J Neurol Sci 19:261-274, 1973.
MUSCLE & NERVE
SeptlOct 1978
415
1:413-415
1978
MYOPATHIES WITH ABNORMAL MITOCHONDRIA= A CLINICOPATHOLOGIC CLASS1FICATION ZOFIA KAMIENIECKA, MD, and HENNING SCHYALBRUCH, MD
In a series of 185 patients with myogenic disorders, muscle biopsies from 2 2 patients were found to contain fibers that stained atypically for mitochondrial enzymes. This report will attempt to classify these patients according to clinical symptoms and histopathologic changes. METHODS
After electromyography was performed, biopsies were taken from a skeletal muscle contralateral to a muscle in which electrophysiologic abnormalities had been foundusually the brachial biceps or the vastus medialis muscle. In two patients, biopsies were taken from the levator palpebrae and the rectus internus oculi muscles, respectively. These methods have been d e ~ c r i b e d . ~ RESULTS General Morphology. In all biopsies, Gomori trichrome
stain showed granular, bright red material in some fibers, both below the sarcolemma and between myofibrils (“ragged red” fibers). After staining for mitochondrial enzymes, clumps of diformazan deposits appeared at the same sites. All of these fibers stained weakly for ATPase
From the Institute of Neurophysiology, University of Copenhagen, Denmark Acknowledgments Electrophystologic findings were evaluated by Professor F Buchthal This work was supported by the Danish Medical Research Council Address reprint requests to Dr Karnteniecka at the Institute of Neurophysiology, University of Copenhagen, Denmark 0148-639XlO10510413$00 OO/O 1978 Houghton Miffltn Professional Publishers
Mitochondria1 Myopathies
at pH 9.4 (type 1); the amount of intracellular fat was increased. In 12 of the 22 patients, abnormal mitochondria were demonstrated by electron microscopy. The following structures were observed: intramitochondrial crystalloids; abnormally small or large “giant” mitochondria; and large subsarcolemmal accumulations of mit~chondria.~.~ Classification of Patients According to Clinical Symptoms. Patients were divided into three groups as
follows (table 1). Gro@ 1. Twelve patients had weakness of the external eye muscles, either alone or associated with weakness of skeletal muscles. Because of these ocular symptoms, many patients in this group had been referred with a diagnosis of “myasthenia.” Six of these 12 patients were 65 to 70 years old, and the onset of their symptoms (i.e., ptosis, ophthalmoplegia) was late. It is possible that some of these patients suffered from senile ptosis. Two patients conformed to the description of the ophthalmoplegia-plus or the oculocraniosomatic synd r ~ m eone ; ~ case was familial, and the inheritance seemed to be autosomal dominant. In both, weakness of external ocular and skeletal muscles was associated with retinal degeneration, involvement of pharyngeal muscles, and cardiac conduction block. One patient was short; one had relatives with short stature, was deaf, and had diabetes mellitus. In 10 of the 12 patients, ragged red muscle fibers were the only pathologic change. The incidence of such fibers was higher in this group of patients than in the others. The biopsy from a 70-year-old patient with bilateral ptosis, ophthalmoplegia, and proximal weakness of skeletal muscles showed, in addition,
MUSCLE & NERVE
SeptlOct 1978
413
Table 1. Clinical and laboratory findings in 22 patients with abnormal mitochondria of muscle.
Number of cases Age (years) Duration (years) Family history EMG indicating or suggesting myopathy Elevated creatine kinase (2-4 x upper limit of normal) Incidence of "ragged red" fibers
I
II
Ocular myopathy or ophthalmoplegia plus
Facioscapulohumeral syndrome
Myositis
Limb-girdle
Other
12 27-70 (mean 58) 2-49 (mean 13) 2
4
2
2 18-67 (mean 45) 1-30 (mean 16) 1
2
37-60 (mean 48) 18-45 (mean 30) 4
12
4
5
6
2
2
5%-25%
fibers with nemaline bodies, lobulated fibers, and "ringbinden." Biopsies from the levator palpebrae and rectus internus oculi muscles, both taken from patients with severe bilateral ophthalmoplegia, consisted mainly of connective tissue and fat; in the levator palpebrae muscle, smooth muscle cells also were present. Croup 2. Four patients had a facioscapulohumeral distribution of weakness: three were in the same family and one had a similarly affected sister. All were women. Abnormal staining for mitochondria1 enzymes was the only pathologic change in three patients; in one patient, who had had symptoms for more than 15 years, the incidence of internal nuclei also was increased. Of the four, two patients, one of whom was abnormally short, had mild cerebellar symptoms. The remaining two had ptosis, and one of these patients was also relatively short. Group 3. Six patients were clinically heterogeneous: none had ptosis or ophthalmoplegia. Two patients had a myositis, two showed a limb-girdle type of weakness, one had a distal distribution of weakness, and in one patient the distribution of weakness was asymmetric. The latter patient had, in addition, a chronic encephalopathy and pericarditis as well as endocarditis. In routine histology, three biopsies were normal, one showed a myositis, and two had pronounced myogenic changes. The patients with myogenic changes had a limb-girdle type of muscular weakness: both abnormal mitochondria and nemaline bodies were present. One of these latter patients had, in addition, histologic signs of denervation. EM6 and Serum Enzymes. In 21 of 22 patients, EMG
indicated or suggested a myopathy; at least one of the muscles investigated was affected. The duration of motor unit action potentials was shortened, and the incidence of polyphasic potentials was increased (fig. 1). The
414
Mitochondria1 Myopathies
111 Heterogeneous
3%-13%
3%-8%
0 Of0
-1 0
z 3
F -20
a
E
3
n
I X XX
z
a W
I 2-40
W
ln
z-50
E
0 0 0
0
0 0 0
E
u
Figure I. Decrease in duration of motor unit action potentials and incidence of polyphasic potentials in 22 patients with abnormal muscle mitochondria. Hatched area: 95% confidence limits of normal. X = patients with ocular involvement; 0 = patients with facioscapulohumeral syndrome; 0 = those from the "heterogeneous" group. Modified with permission from Kamieniecka Z: Myopathies with abnormal mitochondria. A clinical, histological, and e/ectrophysio/ogical study. Acta Neurol Scand 555775, 1976.
MUSCLE 8, NERVE
SepUOct 1978
discrepancy between pronounced electrophysiologic changes and normal routine histology was often quite striking. Serum creatine kinase was two to four times the upper limit of normal in 10 of the 22 patients studied. DISCUSSION
The presented material demonstrates that abnormal muscle mitochondria can be found in different clinical conditions affecting other organs as well. This confirms previous observation^',^*^ and suggests that, at least in some patients, general defects of tissue metabolism existed that were not confined to muscle. When many ragged red fibers were present, and when this was the only histopathologic abnormality, clinical symptoms were predominantly ocular. This indicates that the changes in mitochondria are an early and possibly basic abnormality. In patients with long-lasting facioscapulohumeral distribution of weakness, the biopsy appeared almost normal in routine histology. This is at variance with findings in facioscapulohumeral muscular dystrophy and suggests that the patients described in this study cannot be classified as having muscular dystrophy, although the clinical symptoms were similar. The presence of intramitochondrial crystalloids is,
however, nonspecific; such crystalloids have been found in patients with various neuromuscular disorders5 and in the muscles of mice more than three years old (A. Kelly, 1978, personal communication). In some patients with abnormal muscle mitochondria, oxidative phosphorylation was ~ n c o u p l e d Conversely, .~~~ crystalloids have been produced in rat muscle by uncoupling the phosphorylation.’ Of two patients with oculocraniosomatic syndrome, one had similarly affected relatives. In 23 cases collected from the literature and one case of his own, Karpati et alfi found no familial occurrence. One familial case was reported by Tamura et a1.8 Because relatives are often asymptomatic, familial cases might have been overlooked in previous investigations. A family with a facioscapulohumeral distribution of weakness was described by Hudgson et al;4muscle fibers contained mitochondria1 crystalloids in three affected members, and oxidative phosphorylation was loosely c~upled.~ The combination of nemaline bodies and intramitochondrial crystalloids, previously described only by D’Agostino et a12 in one familial case with limb-girdle distribution ofweakness, occurred in 3 of the 22 patients in the present series.
REFERENCES 1. Castaigne P, Lhermitte F, Escourolle R, Chain F, Fardeau M, Hauw JJ, Curet J, Flavigny C: Etude anatomoclinique d’une
observation d’ophthalmoplegia plus avec analyse des lesions musculaires, nerveuse centrales, oculaires, myocardiques et thyroidiennes. Rev Neurol (Paris) 133:369-386, 1977. 2. D’Agostino AN, Ziter FA, Rallison ML, Bray PF: Familial myopathy with abnormal muscle mitochondria. Arch Neurol 18:388-401, 1968. 3 . DiMauro S, Schotland DL, Bonilla E, Lee CP, Dimauro PMM, Scarpa A: Mitochondrial myopathies: which and how many? I n Milhorat AT (Editor): Exploratoly Concepts in Muscular Dystrophy, Vol 2 . Amsterdam, Excerpta Medica, 1974, p p 506-515. 4. Hudgson P, Bradley WG, Jenkison M: Familial “mitochondrial” myopathy. A myopathy associated with disordered oxidative metabolism in muscle fibres. Part 1. Clinical, electrophysiological and pathological findings. J Neurol Sci 16: 343-370. 1972.
Mitochondrial Myopathies
5. Karnieniecka Z: Myopathies with abnormal mitochondria. A clinical, histological, and electrophysiological study. Acta Neurol Scand 55:57-75, 1976. 6 . Karpati G, Carpenter S, Larbrisseau A, Lafontaine R: The Kearns-Shy syndrome. A multisystem disease with mitochondrial abnormality demonstrated in skeletal muscle and skin. J Neurol Sci 19:133-151, 1973. 7. Melmed C, Karpati G, Carpenter S: Experimental mitochondrial myopathy produced by in uivo uncoupling of oxidative phosphorylation.] Neurol Sci 26:305-318, 1975. 8. Tamura K, Santa T, Kuroiwa Y: Familial oculocranioskeletal neuromuscular disease with abnormal muscle mitochondria. Bruin 97:665-672, 1974. 9. Worsfold M, Park DC, Pennington RJ: Familial “mitochondrial” myopathy. A myopathy associated with disordered oxidative metabolism in muscle fibres. Part 2. Biochemical findings.J Neurol Sci 19:261-274, 1973.
MUSCLE & NERVE
SeptlOct 1978
415
