LETTERS

PROMM Syndrome (Ricker’s Disease) Charles Thornton, MD, Robert C. Griggs, MD, and Richard T . Moxley 111, M D

We reported in Annals on two kindreds affected by a multisystem disease that resembled myotonic dystrophy but was clinically and genetically distinct Ill. Our report, and one by Kenneth Ricker and colleagues [ 2 ] describing similar patients, were submitted almost simultaneously. Dr Row- land’s subsequent letter to the editor referred to this syn- drome as Thornton-Griggs-Moxley syndrome [ 3 ] , an ep- onymic honor that we declined [4} in favor of the term PROMM syndrome coined by Dr Ricker for proximal myo- tonic myopathy. That letter appeared in Annals under the heading ‘Thornton-Griggs-Moxley disease: Myotonic Dys- trophy Type 2.” In the report by Ricker and colleagues [2), linkage data in three kindreds excluded the myotonic dystro- phy gene and all other known genetic loci for myotonic disor- ders. A recent publication by Ricker and colleagues IS] has now summarized the clinical findings in 35 patients with PROMM. D r Ricker has taken a leading role in characteriz- ing this disease and finding the responsible gene or genes. If an eponymic designation is used for this disease, we favor “Ricker’s disease” to honor Dr Ricker’s seminal observations and his major contribution in defining this new disease.

Nerrromuscular Disease Center University of Rochester Medical Center Rochester. NY 14642

References 1. Thornton CA, Griggs RC, Moxley RT 111. Myotonic dystrophy

with no trinucleoride repeat expansion. Ann Neurol 1994;35:

2. h c k e r K, Koch MC, Lehmann-Horn F, et al. Proximal myotonic myopathy: a new dominant disorder with myotonia, muscle weak- ness, and cataracts. Neurology 1994;44:1448-1452

3. Rowland LP. Thornton-Griggs-Moxley disease: myotonic dystro- phy type 2. Ann Neurol 1994;36:803 (Letter)

4. Thornton CA, Griggs RC, Moxley RT. Thornton-Griggs-Moxley disease: myotonic dystrophy type 2. Ann Neurol 1994;36:804 (Reply)

5 . Ricker K, Koch M, Lehmann-Horn F, et al. Proximal myotonic myopathy. Clinical features of a multisystem disorder similar to myotonic dystrophy. Arch Neurol 1995;52:25-3 1

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Agng and Muscle Mitochondrial Abnormalities Josep M. Grau, MD, Jordi Casademont, MD, Francesc Cardellach, MD, and Joaquim Fernindez-Soh, M D

[ 3 ] . Since this subject has been a topic of interest to our Muscle Research Group, we would like to comment further regarding these very interesting observations.

In 1992 we reported 3 patients, age 67 ro 80 years, with a slowly progressive proximal muscle weakness (only 1 of them with associated palpebral ptosis), in whom large mito- chondrial abnormalities were the only pathologic findings in muscle biopsies 141. W e believe that our cases fulfilled the current proposed criteria [ 1) for “late-onset mitochondrial myopathy,” and support the validity of this syndrome. How- ever, in our opinion, not all the proposed criteria should have the same value. First, some criteria are an expected consequence of another one (i.e., elevated resting serum lac- tate levels occurring as a consequence of a deficiency in the activities of oxidative phosphorylation enzymes). On the other hand, other criteria are difficult to interpret in old peo- ple; actually, some authors and ourselves have found a de- cline in mitochondrial respiratory activities in relationship to aging in normal people [5, 61. Ragged-red fibers (RRF) can also be found in muscle biopsies from asymptomatic old peo- ple and mtDNA deletions are frequent and probably non- specific in advanced age. Therefore, we emphasize for non- myologists that the diagnosis of late-onset mitochondrial myopathy should be established only after excluding other potentially treatable conditions in the elderly, such as thyroid dysfunction, polymyalgia rheumatica, autoimmune disorder, and others.

Another point of interest is the relationship between RRF and the inflammatory myopathies. In our experience, unlike the results of Rifai and co-workers [ 2 ] , muscle mitochondrial abnormalities (defined by the presence of RRF in modified trichrome staining) are more frequently associated with “in- flammatory conditions” than with aging itself. In a previous study [ 7 ) of muscle biopsies from a cohort of 52 patients over 60 years, we found 18 muscle biopsies with RRF. The final diagnoses in such cases were dermatomyositis (5 cases), polymyalgia rheumarica (4 ) , polyarteritis nodosa ( 2 ) , systemic scleroderma (I) , and inclusion body myositis (1). Other mis- cellaneous noninflammatory diseases were diagnosed in the last 5 patients. Among the remaining 34 patients, only 11 suffered from any inflammatory disease. The difference in our results from those of Rifai and co-workers 12) may be due to the fact that our criteria for “inflammatory conditions” were not only restricred to inflammatory myopathies but also included other disorders with inflammation such as vasculitis and scleroderma. Our findings are supported by other papers in which mitochondrial abnormalities were clearly demon- strated in polymyalgia rheumatica [S).

Muscle Research Unit HoJpital Clinic Prouincial Vilhrroel 170 08036 Barcelona. Spain

References 1. Johnston W, Karpati G, Carpenter S, et al. Late-onset mitochon-

drial myopathy. Ann Neurol 1995;37: 16-23 2. Ef& z, Welle S, Kmp C, Thornton CA. Rmed-red fibers in

normal aging and inflammatory myopathy. Ann Neurol 1995;37: 24-29

In the January 1995 issue of Annals. the relevance of muscle mitochondrial disturbances found in the aged is covered by two original contributions [ I , 2) and by an editorial comment

Copyright 0 1995 by the American Neurological Association 273