Immunolocalization of several laminin chains in the normal human central and peripheral nervous system

Using specific monoclonal antibodies against different subunits of laminin, we studied the differential distribution pattern of several laminin chains in the central (CNS) and peripheral (PNS) nervous system. Laminin chains alpha 1, beta 1 and gamma 1, were found in the basement membrane (BM) of blood vessels in both CNS and PNS. In contrast, laminin alpha 2 though present in the BM of capillaries in the CNS, was completely absent from PNS capillaries. Laminins alpha 2, beta 1, gamma 1 could be detected in peripheral nerve, in the BM of Schwann cells, which did not contain Laminin alpha 1. The possible importance of laminin alpha 2 for myelination in the PNS as well as in the function of the blood-brain barrier in the CNS, and its potential relevance to the pathology of congenital muscular dystrophy associated with deficiency of this laminin chain, is discussed.

Unusual clinical features and early brain MRI lesions in a family with cerebral autosomal dominant arteriopathy

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a recently described inherited disorder. The pathologic gene maps on chromosome 19. The clinical spectrum of the disease consists of recurrent strokes, migraine, transient ischemic attacks, mood changes, and dementia. We report a genetically assessed CADASIL family with atypical clinical presentations of epileptic seizures. In two asymptomatic family members there were early brain abnormalities on MRI. Our report expands the clinical spectrum of CADASIL and suggests that it is possibly an undiagnosed disorder.

A syndrome of autosomal recessive pontocerebellar hypoplasia with white matter abnormalities and protracted course in two brothers

We describe two brothers with an autosomal recessive syndrome characterized by neonatal onset, severe impairment of cognitive and motor functions, abnormal ocular movements and slight dystonic postures. Brain MR and CT scan showed a reduction in size of the cerebellum and to a lesser extent pons, accompanied by cerebral and cerebellar white matter abnormalities. These data suggest that they have a particular phenotype of pontocerebellar hypoplasia. Extensive laboratory investigation excluded known metabolic causes of pontocerebellar hypoplasia. We discuss the nosological status of pontocerebellar hypoplasia in relation to other early-onset pontocerebellar disorders.

Intracellular detection of laminin alpha 2 chain in skin by electron microscopy immunocytochemistry: comparison between normal and laminin alpha 2 chain deficient subjects

The aim of this study is to localize the alpha 2 laminin chain in normal human skin. The methods used were immuno-gold cytochemistry on cryo-ultramicrotomy sections and thin-section-fracture-label, together with electron microscopy observation. Results were compared with light microscopy peroxidase immuno-staining. Both normal skin samples and skin biopsies from laminin alpha 2 chain deficient congenital muscular dystrophy affected patients were studied. The results show that, in normal skin, the laminin alpha 2 chain is spread throughout the cytoplasm of basal keratinocytes, while it appears associated with desmosomal tonofilaments in the spinous and granular epidermal layers; in skin samples from dystrophic patients the laminin alpha 2 chain was not detectable. These data suggest that the function of the laminin alpha 2 chain is different in the epidermis as compared to that in muscle and peripheral nerve, where it is localized in the basement membrane.

Localization of the laminin alpha 2 chain in normal human skeletal muscle and peripheral nerve: an ultrastructural immunolabeling study

A particular form of congenital muscular dystrophy is associated with a deficiency of the tissue-specific basement membrane protein laminin alpha 2. A more precise knowledge of the normal distribution and localization of laminin alpha 2 would be useful in further elucidating the development of this disorder. In this study we used specific electron microscopic techniques, i.e., thin-section fracture labeling and cryoultramicrotomy in combination with immunogold labeling for laminin alpha 2, to determine its ultrastructural localization in normal human muscle and peripheral nerve. Both in muscle and in peripheral nerve, laminin alpha 2 is found to be associated solely with the basal lamina of myofibers and Schwann cells, respectively. Of special interest is the finding that in peripheral nerve, laminin alpha 2 is associated only with myelinated and not with unmyelinated nerve fibers.

Expression of CD59, a regulator of the membrane attack complex of complement, on human skeletal muscle fibers

Control of complement deposition on autologous cells is mediated by a group of complement regulatory membrane proteins acting at different levels of the complement cascade. Decay accelerating factor (CD55) prevents the assembly of C3 convertases and CD59 membrane inhibitor of reactive lysis (MIRL) restricts homologous complement lysis by the membrane attack complex of complement (MAC) by inhibition of C5b-8 catalyzed insertion of C9. The aim of this work was to study the eventual expression of CD55 and CD59 on human skeletal muscle fibers. Highly sensitive immunoblotting using murine monoclonal antibodies showed that CD59, but not CD55, was present in skeletal muscle fibers. Immunocytochemistry with a monoclonal antibody against CD59 demonstrated a dense granular immunostaining mainly localized at the level of the sarcolemma. Thus, CD59, but not CD55, is expressed on normal skeletal muscle fibers. CD59 may play a prominent role in preventing MAC deposition and subsequent complement-mediated damage in myopathies where the complement system activation is involved.

Localization of laminin chains in the human retina: possible implications for congenital muscular dystrophy associated with alpha 2-chain of laminin deficiency

One recently described form of congenital muscular dystrophy (CMD) is associated with deficiency of the alpha 2-chain of laminin, an extracellular matrix protein that is specifically located in the basement membrane of placental villi, Schwann cells and skeletal muscle in healthy humans. This laminin is also normally present in the skin, kidney and basement membrane of blood vessels of the CNS, though it is absent from the blood vessel walls in other tissues. In this immunohistochemical study, we have explored the presence of the alpha 1, alpha 2, beta 1 and gamma 1 chains of laminin in the normal human retina, which are all localized in the basement membrane of blood vessels. This study adds to the growing evidence that the alpha 2-chain of laminin is selectively expressed in certain tissues, and suggests that CMD associated with a lack of this protein may be a multisystem disorder, with possible direct involvement of the visual system.

An unusual type of primary cerebral hemihypotrophy with signs of dysfunctional neuronal migration

We describe the neuropathological features of a complex brain malformation characterized by cerebral hemihypotrophy with ipsilateral lissencephaly, periventricular nodular heterotopia and macrogyria. The contralateral hemisphere showed only slight alterations of the gyral pattern and a limited periventricular gray matter heterotopia. The clinical picture of the patient, who died at the age of 15 years, consisted of severe oligophrenia, intractable seizures and left hemiparesis. We discuss the nosological status of this neuronal migration disorder of apparently unknown origin.

Acanthocytosis, retinitis pigmentosa, pallidal degeneration. Report of two cases without serum lipid abnormalities

We describe two unrelated patients with Hallervorden-Spatz, disease characterized by prominent facio-bucco-lingual dyskinesia. Acanthocytosis and retinitis pigmentosa were additional findings. Brain MRI showed the typical 'tiger's eye' image of the globus pallidus. This phenotype closely resembled the so-called HARP syndrome (hypoprebetalipoproteinemia, acanthocytosis, retinitis pigmentosa and pallidal degeneration), but extensive serum lipid study failed to demonstrate any lipoprotein abnormality. Our results raise the question whether HARP syndrome is an autonomous entity or a particular phenotype of Hallervorden-Spatz disease.

Clinicopathological and genetic studies of two further Italian families with cerebral autosomal dominant arteriopathy

We report on two Italian families with an early-adult onset autosomal dominant disorder, characterized by leukoencephalopathy, migraine, psychiatric disturbances, stroke and dementia. These findings fulfill the diagnostic criteria for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) syndrome. Moreover, to confirm the CADASIL gene location to 19p12, we performed a linkage analysis with four microsatellite markers. The results of the genetic study gave positive but not significant lod scores, indicating only weak evidence of a linkage with 19p12. In one autopsy case, we found extensive ischemic changes due to the selective involvement of the small muscular arteries of the cerebral white matter. The lesions consisted of a thickening of the media with deposition of granular eosinophilic material. Ultrastructural examination of the arterial walls showed graded damage to smooth muscle cells, mostly of the longitudinal layer, and an abnormal proliferation of basal lamina components. Immunocytochemical analysis showed strong reactivity using antibodies to collagen IV and smooth myosin proteins. The results suggest a primary involvement of the smooth muscle cells of small cerebral arteries, with a secondary alteration of basal lamina components and elastic tissue.

Autosomal recessive paraparesis with amyotrophy of hands and feet and white matter lesions

We report two siblings with a hitherto undescribed syndrome of autosomal recessive spastic paraparesis accompanied by amyotrophy of hands and feet, and mental deterioration. Laboratory tests showed signs of lower motoneuron involvement in the four limbs, more accentuated in the distal regions. Brain MR showed bilateral symmetrical white matter lesions. We discuss the nosological status of this syndrome in relation to other similar forms of "complicated" spastic paraparesis.

The A to G transition at nt 3243 of the mitochondrial tRNALeu(UUR) may cause an MERRF syndrome

OBJECTIVE

To verify the phenotype to genotype correlations of mitochondrial DNA (mtDNA) related disorders in an atypical maternally inherited encephalomyopathy.

METHODS

Neuroradiological, morphological, biochemical, and molecular genetic analyses were performed on the affected members of a pedigree harbouring the heteroplasmic A to G transition at nucleotide 3243 of the mitochondrial tRNALeu(UUR), which is usually associated with the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS).

RESULTS

The proband was affected by a fullblown syndrome of myoclonic epilepsy with ragged red fibres (MERRF), severe brain atrophy, and basal ganglia calcifications, without the MRI T2 hyperintense focal lesions which are pathognomonic of MELAS. Oligosymptomatic relatives were variably affected by lipomas, goitre, brain atrophy, and basal ganglia calcifications. Muscle biopsies in the proband and his mother showed a MELAS-like pattern with cytochrome c oxidase hyperreactive ragged red fibres and strongly succinate dehydrogenase reactive vessels. Quantification of the A3243G mutation disclosed 78% and 70% of mutated mtDNA in the muscle of the severely affected proband and of his oligosymptomatic mother respectively. Nucleotide sequencing of the mitochondrial tRNALeu(UUR) and tRNALys in the proband's muscle failed to show any additional nucleotide change which could account for the clinical oddity of this pedigree by modulating the expression of the primary pathogenic mutation.

CONCLUSION

So far, MERRF has been associated with mutations of the mitochondrial tRNALys, and MELAS with mutations of the mitochondrial tRNALeu(UUR). Now MERRF may also be considered among the clinical syndromes associated with the A to G transition at nt 3243 of the tRNALeu(UUR).

Disappearance of skin lipofuscin storage and marked clinical improvement in adult onset coeliac disease and severe vitamin E deficiency after chronic vitamin E megatherapy

A case of adult onset coeliac disease with IgA and severe vitamin E deficiencies, associated with cerebellar impairment and peripheral neuropathy, is described. Nerve conduction velocities, BAERs and SEP were altered. Brain nMR showed cortical atrophy mainly in the frontal and parietal regions. At ultrastructural examination, nerve biopsy showed a severe nerve fiber loss with presence of lipofuscin. Lipofuscin has been also found in skin and muscle biopsy. Duodenal biopsy showed villar atrophy with criptae hypoplasia. IgA, Apo A1 lipoprotein and cholesterol were decreased. Serum level of vitamin E was not detectable and its amount did not increase after an oral loading (2 g bolus). Parenteral vitamin E administration (900 mg/day) was able to normalize the plasma values only after 6 months of chronic administration of the drug in coincidence with a significant improvement of clinical and neurophysiological signs, and disappearance of lipofuscin storage in the skin biopsy.

Muscular dystrophy, mental retardation and cardiomyopathy not associated with dystrophin deficiency

We report on a male patient aged 38, affected by a syndrome whose characteristic features include onset in early childhood, slow progression, diffuse muscle weakness, mental retardation and cardiomyopathy. Muscle biopsy showed myopathic changes compatible with muscular dystrophy. However, immunostaining for dystrophin as well as 50 and 43 kDa dystrophin-associated glycoproteins (DAGs) was normal. Genetic analysis suggested that direct involvement of the dystrophin gene was highly unlikely. No other family members were affected. Although the clinical picture is reminiscent of Duchenne/Becker muscular dystrophy, the immunologically and genetically documented lack of dystrophin involvement suggests that this particular syndrome is as yet undescribed.

Skin and conjunctive biopsies as a useful diagnostic tool in tomaculous neuropathy

In nerve fascicles from skin and conjunctive biopsies from two siblings with hereditary chronic sensory-motor neuropathy with tomaculous changes (tomaculous neuropathy) we describe similar abnormalities to those found in sural nerve, consisting in thickenings of nerve fibres, with redundant loops of myelin and concentric apposition of enormous number of myelin lamellae. Our data demonstrate that, as previously reported in many neurometabolic or other abiotrophic diseases of the nervous system, skin and conjunctival biopsies may be a useful diagnostic tool also in this disorder, mainly when the diagnosis has to be confirmed in other family members, after one has been fully investigated by nerve biopsy, and when less invasive molecular genetic analyses on peripheral blood DNA have failed to reveal any known mutation associated with the disease.

Autosomal dominant limb girdle myopathy with ragged-red fibers and cardiomyopathy. A pedigree study by in vivo 31P-MR spectroscopy indicating a multisystem mitochondrial defect

We describe a late-onset autosomal dominant limb girdle myopathy, associated with dilated cardiomyopathy and mental deterioration. In two affected members of the pedigree with histochemical (ragged-red and cytocrome c oxidase - negative fibers) and ultrastructural abnormalities of muscle mitochondria, in vivo muscle phosphorus MR spectroscopy disclosed a slow rate of phosphocreatine resynthesis after exercise. Brain phosphorus MR spectroscopy revealed a defect of the energy metabolism in the two patients and in a third asymptomatic member, as shown by a significantly low phosphocreatine, increased ADP and decreased phosphorylation potential. Molecular analysis of muscle mitochondrial DNA failed to reveal any known mutation, including multiple deletions of the mtDNA which have been associated with some autosomal dominant mitochondrial diseases. The multisystem clinical involvement, the presence of ragged-red fibers and the alterations revealed by in vivo brain and muscle 31P-MRS suggest that this limb-girdle syndrome represents an unusual phenotype of mitochondrial cytopathy.

Clinicopathological study of familial late infantile Hallervorden-Spatz disease: a particular form of neuroacanthocytosis

The cases of two sisters with late infantile Hallervorden-Spatz disease are reported, one of whom has died. Autopsy of the deceased patient showed typical pallidal lesions, such as axonal spheroids and iron deposits, without involvement of the substantia nigra. Ultrastructural examination revealed that pallidal axonal enlargements consisted of collection of mitochondria, dense bodies, vesicles and amorphous material. In the living patient, brain MRI showed the classical "tiger's eye" appearance of the globus pallidus. Retinitis pigmentosa, acanthocytosis and slight neuromuscular involvement with an increase in serum creatine kinase were observed in both subjects. The appearance of the globus pallidus on MRI was in line with the pathological abnormalities. Ultrastructural differences between the principal disorders characterized by neuroaxonal dystrophy are compared and the clinical spectrum and similarities of the different forms of neuroacanthocytosis analysed.

Neuronal intranuclear inclusion disease: polymerase chain reaction and ultrastructural study of rectal biopsy specimen in a new case

We report the case of a boy with neuronal intranuclear inclusion disease in whom the diagnosis was made by examination of a rectal biopsy specimen. Intranuclear inclusions were observed in the Auerbach and Meissner plexuses. In an attempt to understand the physiopathology of this very rare disease, we performed polymerase chain reaction (PCR) and reverse transcriptase-PCR analysis for viral nucleic acids of human immunodeficiency virus type 1 (HIV-1), HIV-2, human cytomegalovirus and measles virus. No viral nucleic acids were detected in the biopsy specimen.

Palatal myoclonus and unusual MRI findings in a patient with membranous lipodystrophy

We describe an Italian male patient, deceased at 29 years of age, affected with a syndrome characterized by childhood-onset seizures, mental disorders, motor dysfunction and bilateral palatal myoclonus. Skeletal X-ray examination showed diffuse osteopenia of the tubular bones, and cyst-like lesions in the carpal, metacarpal and tarsal bones bilaterally and in the proximal end of the right femur. Skin biopsy showed subcutaneous and adipose tissue containing membranocystic structures. Cerebral MR and CT scans showed fronto-temporal atrophy, altered signal of the white matter and mineralization of the caudate and dentate nuclei. These findings strongly recall polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy, but in the present case, bone alterations were not prominent; moreover, palatal myoclonus has never previously been described in this syndrome.

Localization of merosin in the normal human brain: implications for congenital muscular dystrophy with merosin deficiency

A particular form of congenital muscular dystrophy with merosin deficiency has recently been described. Magnetic resonance imaging has shown that affected children show brain abnormalities. We investigate the localization of merosin in the normal human brain by immunohistochemistry. Other organs, such as the kidney, lung and liver, were also included in this study. We show that in the normal central nervous system merosin is localized in the basement membrane of blood vessels. No expression of merosin was found at the level of the liver and lungs, whereas the glomerular mesangial matrix of the kidney was intensely positive. These results suggest that merosin deficiency in the basement membrane of blood vessels in the central nervous system could play an important role in the physiopathology of brain abnormalities found in children affected by the congenital muscular dystrophy associated with merosin deficiency. Furthermore, the potential absence of merosin in the glomerular mesangial matrix of the kidney suggests a multi-system involvement.

Ultrastructure and immunoreactivity of dystrophic axons indicate a different pathogenesis of Hallervorden-Spatz disease and infantile neuroaxonal dystrophy

An immunohistochemical and ultrastructural analysis of dystrophic axons (DAs) in the brain and peripheral nerve of a patient with familial infantile neuroaxonal dystrophy (INAD) and in the brain of a patient with familial Hallervorden-Spatz Disease (HSD) revealed prevalent membrano-tubular or granulo-vesicular profiles with a graded pattern of evolution in INAD, while dense bodies, vesicles and amorphous material were present in HSD. DAs immunoreactivity with tai-protein and 200 kDa-neurofilament antibodies was stronger in HSD than in INAD. In both cases immunohistochemistry was positive for ubiquitin and negative for beta-tubulin and beta-amyloid. Distinct ultrastructural features and immunoreactivity pattern of cytoskeletal components suggest different pathogenetic mechanisms.

Early-onset benign limb-girdle myopathy with contractures and facial involvement affecting a father and daughter

We describe a father and daughter with early-onset benign limb-girdle myopathy and contractures of elbows and hands, resembling Bethlem disease. Muscle biopsy showed a pattern of dystrophy with non specific mitochondrial changes. In both patients there was unusual facial muscle weakness. We discuss the nosologic position of Bethlem myopathy and suggest that facial involvement may be an additional feature of this disease.

Amiodarone induced lipidosis similar to Niemann-Pick C disease. Biochemical and morphological study

Amiodarone is effective in the treatment of supraventricular and ventricular cardiac arrhythmia, however a high incidence of toxic side effects has been observed in various organs and tissues during chronic treatment. Ultrastructural observation of affected tissues reveals myelinoid inclusion bodies. The exact pathogenetic mechanism of these changes is still unknown. In this study we investigated the biochemical effects of this drug on lysosomal hydrolases and the alterations induced in subcellular organelles of fibroblasts cultured for 24 h with different concentrations of amiodarone in the medium. Of the enzyme activities assayed, we only observed a significant reduction in sphingomyelinase. Ultrastructural observation of fibroblasts showed swollen lysosomes and a few onionoid inclusion bodies at lower concentrations of the drug; at higher concentrations the lysosomal system was severely impaired. Cytochemical staining of unesterified cholesterol with filipin showed accumulation of cholesterol. We conclude that chronic amiodarone treatment in experimental conditions induces inhibition in sphingomyelinase activity through interaction with membrane lipids and modification of bilayer structure. Higher concentrations of the drug impair cholesterol transport and induce lipid accumulation. These results may be useful for understanding the pathogenesis of induced lipidosis in patients in chronic treatment with amiodarone.