Sarcolemmal defect and subsarcolemmal lesion in a patient with gamma-sarcoglycan deficiency.

We report a case of gamma-sarcoglycanopathy with sarcolemmal defects and subsarcolemmal lesions indistinguishable from those in Duchenne muscular dystrophy. Both disorders share certain ultrastructure features that suggest a common pathogenesis related to primary deficiency of transmembrane glycoproteins (e.g., sarcoglycans) or deficiency in dystrophin, which produces a secondary deficiency in sarcoglycans. The lack of transmembrane glycoproteins may contribute to membrane lesions and associated muscle fiber degeneration and necrosis.

Distinct light microscopic changes in human immunodeficiency virus-associated nemaline myopathy.

The purpose of this study was to compare histologic characteristics of congenital nemaline myopathy (CNM), adult-onset nemaline myopathy (AONM), and human immunodeficiency virus-associated adult-onset nemaline myopathy (HAONM). There was no difference between the pathology of CNM and AONM; however, HAONM had distinctive pathologic features by light microscopy. The fibers in HAONM showed marked intrasarcoplasmic changes, including small vacuoles and granular degeneration.

Abnormal expression of laminin beta 1 chain in skeletal muscle of adult-onset limb-girdle muscular dystrophy.

BACKGROUND: Laminin 2 is a major component of the basal lamina of skeletal muscle cells. It is a heterotrimer composed of 3 chains: merosin (laminin alpha 2 chain), beta 1, and gamma 1. Deficiency of merosin, with or without laminin beta 1 chain reduction, is associated with some forms of congenital muscular dystrophy. Deficient expression of laminin beta 1 chain is also associated with some cases of merosin-positive congenital muscular dystrophy. The expression of laminin 2 subunits has not been well studied in the skeletal muscle of limb-girdle muscular dystrophy (LGMD), nor has much attention been given to the significance of reduction of individual laminin 2 subunits, such as beta 1. OBJECTIVES: To examine the expression of laminin 2 subunits in skeletal muscle in patients with LGMD and to define the clinical features of patients with LGMD who have abnormal expression of laminin 2 subunits. METHODS: We studied muscle biopsy specimens from 18 patients with LGMD using immunofluorescence with antibodies against dystrophin C-terminus, beta-dystroglycan, alpha-sarcoglycan, gamma-sarcoglycan, and the laminin subunits merosin, beta 1, and gamma 1. Of the 18 biopsy specimens, 9 were available for electron microscopic examination of the muscle basement membrane. The clinical features associated with abnormal laminin beta 1 chain immunoreactivity were further described. RESULTS: Laminin beta 1 chain was either barely detectable or severely reduced in 3 cases of patients with LGMD in which the biopsy specimens showed normal staining with the other antibodies. Patients in all 3 cases had common clinical features consistent with a slowly progressive, adult-onset LGMD. Specimens from 2 of the 3 cases that were available for ultrastructural examination showed significant abnormalities of the muscle fiber basement membrane. CONCLUSIONS: Abnormal expression of laminin beta 1 chain without concomitant deficiency of alpha-sarcoglycan in skeletal muscle has not been previously described in LGMD. Reduced laminin beta 1 chain immunoreactivity may potentially serve as a marker for defining subsets of individuals with LGMD, in particular those with slowly progressive, adult-onset pelvifemoral presentation. The abnormality of muscle fiber basement membranes in specimens from cases that were available for ultrastructural study suggests that defects in the extracellular matrix may play a role in the pathogenesis of this subset of LGMD.

Neonatal adrenoleukodystrophy presenting as infantile progressive spinal muscular atrophy.

Two siblings with neonatal adrenoleukodystrophy are described. The signs and laboratory data documenting infantile progressive spinal muscular atrophy included the initial presentation of 1 sibling with neonatal adrenoleukodystrophy. These patients indicate that neonatal adrenoleukodystrophy should be considered in the differential diagnosis of infantile progressive spinal muscular atrophy.

Intragenic deletions in 21 Duchenne muscular dystrophy (DMD)/Becker muscular dystrophy (BMD) families studied with the dystrophin cDNA: location of breakpoints on HindIII and BglII exon-containing fragment maps, meiotic and mitotic origin of the mutations.

Following the strategy outlined in an accompanying paper, we studied 32 X-linked muscular dystrophy families (29 Duchenne [DMD] and three Becker [BMD] type) for abnormalities of HindIII and BglII fragments detected by the entire dystrophin cDNA. Twenty-one different single-intragenic deletions, and no duplications, were identified. The deletion endpoints were precisely mapped on the published HindIII fragment map. Detailed analysis of overlapping deletions led to clarification of the fragment order for some previously unsettled regions of the HindIII map and to the construction of a partial map of exon-containing BglII fragments. For the regions involved in deletions, the corresponding HindIII and BglIII fragments could be identified. Noncontiguous comigrating fragments were detected in two regions by careful analysis of the patterns in deletion patients. Four of the 21 deletions generated novel restriction fragments that facilitated detection of female carriers in these families. Twelve of the deletions had a breakpoint in one of the two large introns known to be the sites of breakpoint clusters. By combining deletions and RFLP analyses, we unequivocally identified the gamete that first carried the mutation in 13 families: eight oocytes and five sperm. Germ-line mosaicism previously detected in one male was confirmed by cDNA studies. In two additional families gonadal mosaicism was found in females. As evidence is accumulating for frequent mitotic origin of these deletion mutations, this phenomenon has to be considered when postulating mutational mechanisms and in genetic counseling of DMD/BMD families.

Gastroesophageal reflux associated with nemaline myopathy of infancy.

A severe infantile form of nemaline myopathy has a high mortality rate when untreated because of subsequent malnutrition and respiratory failure. Three infants with this condition demonstrated persistent vomiting, poor weight gain, and recurrent pneumonias. Esophageal manometry demonstrated decreased lower esophageal sphincter pressures and low amplitude peristalsis; 24-hour esophageal pH monitoring revealed significant gastroesophageal reflux. Medical therapy was ineffective in relieving symptoms. After antireflux surgery, vomiting and respiratory symptoms ceased, and there was no longer significant gastroesophageal reflux during pH monitoring. Our experience indicates that in some infants with nemaline myopathy a severe form of gastroesophageal reflux develops that is not responsive to medical therapy. Early surgical intervention may decrease life-threatening complications associated with gastroesophageal reflux in these infants.

The coexistence of myasthenia gravis and myotonic dystrophy in one family.

We are reporting the unique coexistence of two distinct neuromuscular diseases, myotonic dystrophy and the juvenile form of myasthenia gravis, occurring in one family. A 16-month-old previously healthy female presented with a two month history of bilateral varying drooping of both eyelids and bilateral external ophthalmoparesis. The acetylcholine receptor antibodies were elevated, and there was a dramatic response to edrophonium confirming the clinical impression of myasthenia gravis. Spontaneous remission of the ptosis was noted after six months with no specific treatment. Many other family members were examined; none of them had clinical or laboratory evidence of myasthenia gravis. The clinical examination of the mother and the maternal grandmother, neither of whom had any complaints, resulted in a definite diagnosis of myotonic dystrophy. The proband's father and a 3-year-old sister were examined and found to be normal. We studied the HLA antigens of all of the available family members; none were found to have the HLA antigens most commonly associated with myasthenia gravis. Secretor gene studies were not helpful in providing additional genetic identification. The question generated by the coexistence of these two uncommon disorders in one family is if there is a genetic or other relationship between them or if this was merely a coincidental occurrence. At this point in time the question remains unanswered and must await demonstration of additional similar circumstances.

Duchenne dystrophic muscle develops lesions in long-term coculture with mouse spinal cord.

When strips of human skeletal muscle from biopsies of normal children and donors with Duchenne muscular dystrophy (DMD) are explanted in organotypic coculture with fetal mouse spinal cord, many regenerating muscle fibers develop, become innervated, and maintain a remarkable degree of mature structure and function for more than 3-6 months in vitro. Sequential light microscopy in correlation with electron-microscopic and electrophysiologic analyses showed that despite cross-species innervation, these human muscle fibers develop stable cross-striations, peripherally positioned myonuclei, and mature, functional motor endplates. Of special interest is the onset of significant progressive abnormalities, e.g., unusual focal myofibrillar lesions, in substantial numbers of innervated mature DMD muscle fibers after 2-4 months in culture. The focal myofibrillar lesions were not detected in normal muscle fibers maintained as long as 6 months in coculture, nor are they comparable to the generalized loss of cross-striations observed in muscle atrophy following in vitro denervation of mature DMD fibers.

Pseudo-Zellweger syndrome: deficiencies in several peroxisomal oxidative activities.

We describe an infant girl with a clinical, chemical, and pathologic syndrome remarkably similar to Zellweger cerebrohepatorenal syndrome but whose liver parenchymal cells contained abundant peroxisomes. Peroxisomal L-alpha hydroxy acid oxidase, catalase, and the plasmalogen synthesizing enzyme dihydroxy acetone phosphate-acyl transferase activities were normal; other peroxisomal enzymatic activities, including fatty acyl-CoA oxidase and D-amino acid oxidase, were reduced by 80% to 85%. Oxidation of bile acids and pipecolic acid was also deficient. Autopsy revealed the presence of neuronal heterotopia, renal cortical cysts, adrenal atrophy, and accumulation of very long chain fatty acids. The clinical and pathologic features of this case of "pseudo-Zellweger syndrome" reflect a deficiency in multiple peroxisomal activities rather than a defect in peroxisomal biogenesis. The deficient enzymatic activities require flavin adenine dinucleotide, and the underlying defect may be in the utilization of this cofactor.

Neurological complications in infants and children with acquired immune deficiency syndrome.

Neurological complications occurred in 6 children, aged 6 months to 5 years, with acquired immune deficiency syndrome who were followed for 14 months. The most frequent manifestations included encephalopathies, acquired microcephaly, and pyramidal tract signs. Computed tomographic examinations showed variable degrees of cortical atrophy with ventricular dilatation and calcification. Electrophysiological abnormalities were demonstrated. Two children had documented central nervous system infections. Neurological deterioration resulted in dementia in 3 children. Cognitive impairment and developmental delays were evident in the other 3. Postmortem examination of the 3 children who died showed subacute cytomegalovirus encephalitis in 1; nonspecific hemispheric white matter changes, calcific vasopathy of the basal ganglia, and striking bilateral corticospinal tract degeneration in the second; and extensive calcific vasopathy of the basal ganglia and frontal centrum semiovale, and bilateral attenuation of the frontopontine and corticospinal tracts in the third.

Ipecac-induced myopathy simulating dermatomyositis.

We studied a young woman with an eating disorder. To induce vomiting, she took syrup of ipecac daily for 2 years, and then developed insidious, progressive muscle weakness. Skin findings were similar to those of dermatomyositis. Muscle biopsy, however, was similar to experimental emetine myopathy and lacked inflammatory features. Upon cessation of ipecac abuse, strength returned. We believe that this patient had ipecac-induced muscle weakness.

'Stiff-man syndrome' in an adolescent.

A 16-year-old body with stiff-man syndrome is described because the condition rarely occurs in this age group. Diagnosis, by appropriate electrodiagnostic studies, is important because stiff-man syndrome is easily treated with high doses of diazepam.

Disuse atrophy of skeletal muscle. A morphometric study using image analysis.

A morphometric study of disuse atrophy was done on the rat anterior tibilalis muscle over a 13-day period after immobilization of the hind leg by pinning the knee and ankle joints. Cross-sectional areas of individual muscle fibers were measured using image analysis, a new and precise technique. Three types of muscle fibers, light, medium and dark, were defined using a modified myosin-ATPase reaction on cryostat-cut sections. Each of the 3 fiber types was found to show a degree and time course of atrophy unique to itself. At the 0.01 confidence level, the dark fibers (with strongest ATPase reaction) did not shrink significantly. Both the light (ATPase negative) and medium fiber did show significant atrophy at that level; the light shrinking more than the medium. Simple visualization of the light microscopic images was often found to be misleading. Thus, the need was documented for a precise technique for analysis of fiber size distribution.

Ultrastructure of thalamic neuronal inclusions in myotonic dystrophy.

Recently, the presence of thalamic neuronal cytoplasmic inclusions in patients with myotonic dystrophy has been reported. At the ultrastructural level, the inclusions were described "containing a fibrillar material within a limiting membrane studded on its outer surface with ribosomes". We have studied the brain of a 48-year-old woman with myotonic dystrophy. Many neuronal inclusion bodies were found within the thalamus, and examined in the electron microscope. Inclusions were found to have an electron density resembling that of nuclear chromatin, were not membrane-bound, and had an internal structure composed of parallel alternating dark and pale lines. We confirm the previously-reported existence of cytoplasmic thalamic neuronal inclusions in myotonic dystrophy, but differ in our observations of their ultrastructural appearance, and note that these inclusions bear no resemblance to previously described inclusion bodies.