Moris J. Danon

Lysosomal glycogen storage disease with normal acid maltase

Two unrelated 16-year-old boys had mental retardation, cardiomegaly, and proximal myopathy. One also had hepatomegaly. Histochemistry and electronmicroscopy of muscle biopsies showed lysosomal glycogen storage resembling acid maltase deficiency. Biochemical studies of skeletal muscle showed increased content of glycogen of normal structure; acid a-glucosidase activity in both urine and muscle was normal. Other enzymes of glycogen metabolism were also normal. The cause of this apparently generalized glycogenosis with no demonstrable enzyme defect is unknown.

Mitochondrial myopathy of childhood associated with depletion of mitochondrial DNA

We have studied five children with mitochondrial myopathy manifesting within or soon after the first year of life. Muscle biopsies showed ragged-red fibers and decreased respiratory chain activity. All five patients had a severe decrease (2 to 34% of normal) in the amount of muscle mitochondrial DNA (mtDNA). The depletion of mtDNA correlated with absence of mtDNA-encoded translation products and with loss of cytochrome c oxidase enzyme activity in individual muscle fibers. This mitochondrial myopathy of childhood illustrates one phenotypic expression of a novel pathogenetic mechanism in mitochondrial diseases, the specific depletion of mtDNA in affected tissues.

Fatal infantile glycogen storage disease Deficiency of phosphofructokinase and phosphorylase b kinase

A girl with congenital limb weakness, mental retardation, and corneal ulceration died with respiratory insufficiency at age 4 years. Histochemistry of muscle biopsy showed only nonspecific myopathy, but electronmicroscopy revealed subsarcolemmal and intramyofibrillar accumulation of glycogen. Biochemical studies showed increased glycogen content of muscle with lack of phosphofructokinase. Phosphorylase b kinase activity was about 30% of normal. The relationship of the double enzyme deficiency to this unusual clinical picture is unclear.

Tubular aggregates: their association with myalgia.

Three thousand consecutive muscle biopsies were reviewed for the presence of tubular aggregates and their association with clinical symptomatology. Tubular aggregates were detected in 19 patients (0.6%). Twelve of these nineteen patients had severe myalgia, and the most abundant tubular aggregates were found in biopsies of patients with myalgia. Seven patients had only myalgia as their clinical symptomatology with normal physical examination. An additional five patients with tubular aggregates and myalgia had concomitant amyotrophic lateral sclerosis (2) or neuropathy (3). The high incidence of myalgia associated with tubular aggregates in our patients and the fact that tubular aggregates originate from sarcoplasmic reticulum suggest a role played by this structure in the pathogenesis of myalgia.

Sarcoplasmic reticulum adenosine triphosphatase deficiency with probable autosomal dominant inheritance

We report a family in which four members in two generations (mother, her son, and two daughters) suffered from impaired muscle relaxation aggravated by exercise. Muscle biopsies from two sisters showed moderate degree of histochemical type 2 fiber atrophy and excess of internal nuclei. Microscopic immunocytochemistry, using a monoclonal antibody raised against purified chicken SR-ATPase, revealed severe reduction of the immunoreactive SR-ATPase protein limited to histochemical type 2 fibers. Immunoreactive Ca2+-ATPase of SR was markedly decreased on Western blots of muscle proteins. This family appears to have a clinically, electromyographically, and biochemically distinct metabolic myopathy associated with deficiency of SR-ATPase, with a probable autosomal dominant inheritance pattern that is phenotypically similar to recently described recessive cases.

Late‐onset muscle phosphofructokinase deficiency

A 75-year-old man had a 10-year history of slowly progressive limb weakness without cramps or myoglobinuria. Clinical, morphologic, and biochemical studies showed muscle phosphofructokinase (PFK) deficiency. Erythrocyte PFK activity in his asymptomatic daughter was 63% of normal, compatible with a carrier state. The chronic myopathic variant of muscle PFK deficiency appears to be transmitted as an autosomal recessive trait and may be due to a distinct genetic defect.

Inclusion body myositis associated with systemic sarcoidosis.

We report an autopsy study of a 64-year-old female with systemic sarcoidosis. In addition many muscles showed typical light and electron microscopic features of inclusion body myositis. To our knowledge this association has not been previously reported.

Inclusion Body Myositis Associated with Progressive Dysphagia: Treatment with Cricopharyngeal Myotomy

A 68-year-old man known to have inclusion body myositis underwent a cricopharyngeal myotomy in an attempt to improve his progressive dysphagia. Morphological studies from tissues obtained during this procedure showed the diagnostic features typical of this chronic inflammatory myopathy. To our knowledge this is the first pathological demonstration of inclusion body myositis involving the pharyngeal skeletal musculature.

Juvenile‐onset acid maltase deficiency with unusual familial features

From early childhood, two brothers had mild gait difficulties due to acid maltase deficiency (AMD). Biochemical studies of family members were consistent with autosomal recessive inheritance, but the asymptomatic mother had AM activity in the homozygote range, and her parents had decreased AM activity. The asymptomatic mother may be homozygous for the adult-onset variant of AMD. Alternatively, either the mother or the children may be genetic compounds of the childhood and adult forms of AMD.

Hypokalemic periodic paralysis with unusual responses to acetazolamide and sympathomimetics

Five members in three generations of a family were affected by an illness that had many clinical features of the hypokalemic form of periodic paralysis (HPP). The serum potassium was either moderately reduced or normal during attacks, and there was no evidence of myotonia or cold-intolerance. All of the patients improved to a variable degree with oral potassium supplements, and 3 responded favorably to triamterene. The usually beneficial drug acetazolamide, however, invariably caused weakness in these patients, an effect previously described in only one other family with HPP. In addition, amphetamine-like sympathomimetic drugs effectively aborted or prevented paralysis in several members. Muscle biopsy in two patients revealed some unusual features, and electromyography showed myopathic potentials. There was no evidence of diabetes. The urine electrolyte concentrations during glucose tolerance tests, however, were different from those previously reported in HPP. This family may represent a variant form of HPP.