Autosomal dominant sensory ataxia: a neuroaxonal dystrophy

Autosomal dominant sensory ataxia (ADSA), a rare hereditary ataxia, is characterized by progressive dysfunction of central sensory pathways. Its pathological features have not been previously documented. We report a case of a 61-year-old man with ADSA who died of congestive heart failure. Autopsy specimens of brain, thoracolumbar spinal cord, peripheral nerve and skeletal muscle were examined. There was no abnormality on gross examination. Microscopically, there were occasional swollen axons within the cerebral cortex and deep nuclei, particularly the subthalamic nucleus, with no neuronal loss, gliosis or microglial activation. There were many axonal spheroids within the medulla, particularly in the dorsal column nuclei. Axonal spheroids were also seen in the dorsal columns and ventral horns in the thoracolumbar spinal cord, but there was no Wallerian degeneration or demyelination. Amyloid precursor protein (APP) immunostaining of some of the spheroids suggested continuing dysfunction of axoplasmic flow in some regions. There was mild inflammation of peripheral nerve roots but no spheroid, and patchy chronic inflammation of skeletal muscle. In summary, the major pathological process in ADSA is a neuroaxonal dystrophy most prominent in the dorsal columns and dorsal column nuclei, consistent with the clinical pattern of central sensory pathway degeneration.     

MRI as an aid for diagnosis of infantile neuroaxonal dystrophy]

We experienced a 5-year-old girl, who had presented with nystagmus and psychomotor regression since 1 year old. No clinical diagnosis had been made despite various examinations including lysosomal enzymes and muscle biopsy. Her brain magnetic resonance imaging (MRI) revealed increased a T2 signal in bilateral cerebellar hemisphere. Recently this MRI finding was reported as a typical feature of infantile neuroaxonal dystrophy (INAD). Then we performed the second biopsy from her peripheral nerve, and diagnosed her as having INAD. It was suggested that MRI was a useful aid for the diagnosis of INAD.     

Infantile neuroaxonal dystrophy: report of 2 cases

We describe two cases of infantile neuroaxonal dystrophy, which is a rare, neurodegenerative disease, with autosomal recessive inheritance. The first case was an 8 year old boy, with arrested motor and mental development, ataxia and muscle weakness. On physical examination there was horizontal and vertical nystagmus, optic disc atrophy, hypotonia; deep tendon reflexes were absent. The second case was a 1.6 year old boy with arrested motor and mental development, and seizures. On physical examination there was optic atrophy, hypertonia and hyperreflexia. Both patients had on sural nerve biopsy neuronal enlargement, consistent with neuroaxonal dystrophy. Diagnosis without pathological confirmation with neuroaxonal spheroids is very difficult, because the clinical picture is variable and the neurophysiological findings are non specific.     

Infantile neuroaxonal dystrophy: clinical spectrum and diagnostic criteria

OBJECTIVE: To present clinical, neurophysiologic, and neuroradiologic findings in 13 patients with infantile neuroaxonal dystrophy (INAD), focusing on aspects that assist early diagnosis. BACKGROUND: Clinicopathologic diagnostic criteria for INAD were delineated by Aicardi and Castelein in 1979, but atypical cases are reported frequently and little is known of the diagnostic utility of MRI. METHODS: The authors reviewed the clinical, neurophysiologic, and MRI findings of 13 patients who met the diagnostic criteria for INAD. RESULTS: Symptoms onset was between 6 months and 2 years of age. In nine patients the clinical course was typical, with rapid motor and mental deterioration; in four patients progression was slower and the clinical picture was different. Electromyographic (EMG) signs of chronic denervation, fast rhythms on EEG and abnormal visual evoked potentials were observed in all patients during the disease course. Cerebellar atrophy with signal hyperintensity in the cerebellar cortex on T2-weighted images were the most characteristic MRI findings; hypointensity in the pallida and substantia nigra was also observed in two patients. alpha-N-acetyl-galactosaminidase activity on leukocytes was normal in the 10 patients tested. CONCLUSIONS: EMG and MRI abnormalities are the earliest and most suggestive signs of INAD, which has a clinical and radiologic spectrum that is broader than reported previously.     

Infantile neuroaxonal dystrophy and pantothenate-kinase-associated neurodegeneration: locus heterogeneity

Common clinical, radiologic, and pathologic features in infantile neuroaxonal dystrophy (INAD) and pantothenate kinase-associated neurodegeneration (PKAN) have led to the hypothesis of an allelic relationship. With the discovery of the gene defect in PKAN, this can now be tested directly. The authors excluded linkage in one consanguineous INAD family by haplotype analysis. Moreover, sequencing in seven INAD families revealed no mutations in PANK2 or in other genes of CoA biogenesis. Thus, INAD and PKAN are genetically heterogeneous disorders.     

Histological and ultrastructural features of dystrophic isocortical axons in infantile neuroaxonal dystrophy (Seitelberger's disease)

Summary The histological and ultrastructural features of axonal swellings are described in a cerebral biopsy specimen from a 6-year-old girl with infantile neuroaxonal dystrophy. In agreement with previous reports, several swellings were identified as axonal terminals, and it is postulated that the prevailing axonal swellings in cerebral cortex represent dystrophic boutons. Microscopically, dystrophic cortical boutons are morphologically different from typical subcortical spheroids and can be easily identified in routine histological preparations. Five ultrastructural elements were present in most axonal swellings: clusters of characteristic membranous bodies, stacks of elongated membranes, mitochondria, groups of vesicles, and an amorphous matrix. In spite of widespread axonal enlargement, the cerebral cortex was not thickened, and, in fact, the gyri looked atrophic in computerized axial tomograms. These findings suggest that some normal cortical element must be deficient, but such a structure remains to be identified.     

Infantile neuroaxonal dystrophy: Cortical axonic and presynaptic changes

Summary A 21/2 year old girl who, since the age of 1 year presented, a progressive psychomotor retardation. A cortical biopsy appeared normal by light microscopy, but by electron microscopy an abundance of dilated spheroid-like axons were found. They contained either vesiculo-tubular material or densly packed filamentous material. Synapses were demonstrated between the spheroids and other neuronal bodies or dendrites. Crystalline like material was observed within mitochondria and the spheroids. It is suggested that Neuroaxonal dystrophy may be diagnosed by cortical brain biopsy.

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Zusammenfassung Ein 21/2 Jahre altes arabisches Mädchen (Eltern Cousins 2. Grades) bot seit dem 1. Lebensjahr progressive psychomotorische Retardierung. Eine Hirnrindenbiopsie ergab normale lichtoptische Verhältnisse, während elektronenoptisch reichlich schollenartige Axonauftreibungen gefunden wurden. Ihr Inhalt setzte sich aus vesico-tubulärem Material oder aus dicht gepacktem filamentösen Material zusammen. Synapsen waren zwischen den Sphäroiden und anderen neuronalen Somata sowie Dendriten nachweisbar. In den Mitochondrien und Sphäroiden fanden sich kristalline Strukturen. Es wird vermutet, daß die neuroaxonale Dystrophie durch Rindenbiopsie diagnostiziert werden kann.

     

Infantile neuroaxonal dystrophy: diagnosis by skin biopsy.

A child who shows progressive motor and mental deterioration after the first year of life, who has pyramidal signs, marked muscle hypotonia, but no seizures, suggests to have infantile neuroaxonal dystrophy (INAD). Beyond the age of two years, the EEG also entails characteristic findings. Diagnosis may be obtained by an ultrastructural examination of biopsied skin. The respective clinical and morphological findings are recorded and illustrated from four patients in this report.     

A case of infantile neuroaxonal dystrophy: connatal Seitelberger disease

We present a male stillbirth with infantile neuroaxonal dystrophy (connatal Seitelberger disease). Following the development of polyhydramnios with an ultrasound scan showing severe distal arthrogryposis, the mother was induced at 38 weeks. A moderately macerated severely intrauterine growth restricted male stillbirth was delivered. External microcephaly, sloping forehead, simplified palmar skin creases, fixed flexion deformities of the knees, severe talipes equinovarus, spinal scoliosis, and empty scrotum were present. The brain was microcephalic with normal gyration, having a hypoplastic corpus callosum, thinned insular cortex, and enlarged lateral ventricles. There was a progressive increase in axonal spheroids going in a rostrocaudal direction in the central nervous system with the preferential distal denervation of muscles, with their motor nerves showing axonal spheroids. The presence of axonal spheroids in both the central and peripheral nervous systems and electron microscopic appearances were diagnostic of infantile neuroaxonal dystrophy occurring in utero.     

Juvenile neuroaxonal dystrophy in a Rottweiler: accumulation of synaptic proteins in dystrophic axons

Dystrophic axons in a 2-year-old male Rottweiler with neuroaxonal dystrophy have shown synaptophysin, synapsin-I, synaptosomal-associated protein of 25 kDa (SNAP-25), Rab 3a, and alpha-synuclein immunoreactivity. Similar findings have been observed in isolated dystrophic axons in the nuclei gracillis and cunneatus in five dogs aged between 14 and 18 years. Abnormal expression of integral synaptic vesicle, synaptic vesicle-associated presynaptic plasma membrane and cytosolic proteins, which participate in the trafficking, docking and fusion of the synaptic vesicle to the plasma membrane, suggest severe disruption of axonal transport in dystrophic axons in canine neuroaxonal dystrophy.     

Infantile neuroaxonal dystrophy: perinatal onset with symptoms of diencephalic syndrome

In a neonatal case of infantile neuroaxonal dystrophy, there was emaciation, nystagmus, and endocrinologic disorder suggesting the diencephalic syndrome. At autopsy, spheroid bodies were widely disseminated, particularly in the hypothalamus, infundibulum, and neurohypophysis. The pathologic process may have started in utero.     

Ictal and nonictal paroxysmal events in infantile neuroaxonal dystrophy: polygraphic study of a case

A 7.5-year-old girl, with infantile neuroaxonal dystrophy (INAD), showed a gradual deterioration from 16 months; at age 5 years she was bedridden, with severe tetraplegia, strabismus, nystagmus and optic atrophy, and dementia. From age 5.5 years, she had paroxysmal tonic events. Videopolygraphic recordings disclosed two different kinds of motor events: (a) epileptic tonic seizures, in wakefulness and sleep, associated with autonomic changes and ictal EEG discharges; and (b) nonepileptic prolonged clusters of brief tonic spasms, without ictal modifications of the EEG. Both motor events were characterized by a minimal and clinically similar tonic contraction of the upper extremities. Video-polygraphic studies are mandatory for a correct paroxysmal event classification and treatment in INAD patients.     

Infantile neuroaxonal dystrophy and giant axonal neuropathy: Are they related?

Light and electron microscopic findings from two sural nerve biopsies obtained at a one-year interval from a patient with the clinical features of Seitelberger's disease are described. Ballooned axons with accumulations of membranous profiles, vesicles, mitochondria, and a homogeneous center were present, and there were masses of 90 A filaments in endothelial, endoneurial, perineurial, and Schwann cells. These pathological alterations were less prominent in the second nerve biopsy, which showed a more pronounced decrease in myelinated fibers. The case shows that a generalized increase of 90 A filaments in structures of the peripheral nervous system is not a phenomenon exclusively occurring in patients with giant axonal neuropathy and, furthermore, that it may be a transitory feature.     

Juvenile neuroaxonal dystrophy: clinical, electrophysiological, and neuropathological features.

We describe 2 brothers with progressive myoclonus epilepsy that began in the second decade and was associated with cerebellar ataxia and intellectual deterioration. Electroencephalographic and cerebral evoked potential studies showed findings associated with myoclonus epilepsy. Neuropathological examination of 1 of the brothers, who died at age 23 years, revealed widespread changes of neuroaxonal dystrophy without pigment deposition in the basal ganglia. We propose the term juvenile neuroaxonal dystrophy (JNAD) to distinguish this condition on clinical grounds from infantile neuroaxonal dystrophy on the one hand, and on clinical and pathological grounds from Hallervorden-Spatz disease on the other hand. JNAD, while exceedinly rare, must be considered in the differential diagnosis of the progressive myoclonus epilepsies.     

Infantile neuroaxonal dystrophy: diagnosis during life by biopsy of the conjunctiva

Three cases of infantile neuroaxonal dystrophy diagnosed by conjunctival biopsy are reported. Some axons of the conjunctival nerves showed aggregates of tubular and membranous structures identical to the spheroids of the CNS. The visualization of these structures is the only diagnostic tool in this disease of unknown metabolic basis. Conjunctival biopsy which is ease to perform is the preferential technique for the diagnosis of this disease. Clinically, the intense hypotonia with pyramidal tract signs, the absence of seizures, the cerebellar atrophy observed at the computerized tomography suggest strongly the diagnosis of infantile neuroaxonal dystrophy.