Skin and conjunctival biopsies in adrenoleukodystrophy

Diabetic neuropathy and nerve regeneration

Diabetic neuropathy is the most common peripheral neuropathy in western countries. Although every effort has been made to clarify the pathogenic mechanism of diabetic neuropathy, thereby devising its ideal therapeutic drugs, neither convinced hypotheses nor unequivocally effective drugs have been established. In view of the pathologic basis for the treatment of diabetic neuropathy, it is important to enhance nerve regeneration as well as prevent nerve degeneration. Nerve regeneration or sprouting in diabetes may occur not only in the nerve trunk but also in the dermis and around dorsal root ganglion neurons, thereby being implicated in the generation of pain sensation. Thus, inadequate nerve regeneration unequivocally contributes to the pathophysiologic mechanism of diabetic neuropathy. In this context, the research on nerve regeneration in diabetes should be more accelerated. Indeed, nerve regenerative capacity has been shown to be decreased in diabetic patients as well as in diabetic animals. Disturbed nerve regeneration in diabetes has been ascribed at least in part to all or some of decreased levels of neurotrophic factors, decreased expression of their receptors, altered cellular signal pathways and/or abnormal expression of cell adhesion molecules, although the mechanisms of their changes remain almost unclear. In addition to their steady-state changes in diabetes, nerve injury induces injury-specific changes in individual neurotrophic factors, their receptors and their intracellular signal pathways, which are closely linked with altered neuronal function, varying from neuronal survival and neurite extension/nerve regeneration to apoptosis. Although it is essential to clarify those changes for understanding the mechanism of disturbed nerve regeneration in diabetes, very few data are now available. Rationally accepted replacement therapy with neurotrophic factors has not provided any success in treating diabetic neuropathy. Aside from adverse effects of those factors, more rigorous consideration for their delivery system may be needed for any possible success. Although conventional therapeutic drugs like aldose reductase (AR) inhibitors and vasodilators have been shown to enhance nerve regeneration, their efficacy should be strictly evaluated with respect to nerve regenerative capacity. For this purpose, especially clinically, skin biopsy, by which cutaneous nerve pathology including nerve regeneration can be morphometrically evaluated, might be a safe and useful examination.

Electron microscopic features of skin in neurometabolic disorders

Skin biopsy may contribute to the clinical diagnosis of neurometabolic disorders. It is an easy and much less traumatic procedure than brain, rectal, peripheral nerve and skeletal muscle biopsies. The method is informative and not too time-consuming for an experienced examiner. Differential diagnosis is possible in most storage disorders since the ultrastructure of the storage is virtually typical in lysosomal and in nonlysosomal diseases. The storage has a particular distribution with characteristic ultrastructural patterns in the various cell types. Skin biopsy plays a major diagnostic role when clinical features are atypical for a storage disorder, to discover new phenotypic variants of known enzymatic deficiencies or when the biochemical defect has not yet been determined. It can be used as a screening procedure to orientate the investigations, to suggest specific biochemical assays on cultured fibroblasts or other tissues or body fluids. It can be applied to detect "presymptomatic" patients in affected families. Other disorders of the nervous system should be investigated in the future to ascertain whether skin biopsies could possibly be used for diagnostic purposes. Thorough knowledge of the morphological features of these disorders may also improve the understanding of their pathogenesis, shed some light on the underlying basic defects and control the results of therapy.

Adrenoleukodystrophy: frequency of presentation as a psychiatric disorder

Adrenoleukodystrophy (ALD) is an inheritable clinical disorder in which very long chain fatty acids accumulate in several tissue types. ALD is underrepresented in the psychiatric literature, although the disorder may cause an organic brain syndrome, often misdiagnosed as another psychiatric problem. A survey of 109 reported cases of ALD revealed that 39% presented with some psychiatric sign or symptom, whereas 17% presented exclusively as a psychiatric problem. A computed axial tomogram (CAT) head scan is recommended to rule out ALD in psychiatric patients suspected of having organic brain disease, as a characteristic image may be found in ALD patients who have brain involvement.

Ophthalmologic manifestations of X-linked childhood adrenoleukodystrophy

The ophthalmologic findings in 15 patients with childhood adrenoleukodystrophy (ALD) are reviewed. In this X-linked demyelinating disease with adrenal dysfunction, relentlessly progressive visual loss followed by optic atrophy occurs months to years after the diagnosis is established based on neurologic symptoms and biochemical abnormalities. Visual loss is mainly due to central nervous system (CNS) demyelination involving the visual tracts, but primary retinal ganglion cell degeneration may also be operative. All patients in this study were male. Vision ranged from 20/20 to no light perception (NLP). All but one patient with bilateral cataracts had normal anterior segment examinations. Seven patients had exotropia, and esotropia developed in one patient. Electroretinography (ERG) and electrooculography (EOG) findings were normal in two patients with severe visual loss. Macular pigmentary changes were observed in three patients. Optic pallor was noticed in seven patients. Optic nerve hypoplasia was seen in one patient. Visual-evoked responses were abnormal in two patients and borderline in one. Progressive visual field abnormalities were noticed in three patients, large field cuts in two patients, and normal fields in another two patients. The diagnosis of ALD should be considered in all boys presenting with unexplained visual loss, dementia, and adrenal dysfunction.

Skin biopsy as a beneficial procedure for morphological evaluation of diabetic neuropathy

In an attempt to evaluate the morphological abnormalities of dermal non-myelinated nerve fibers of diabetics and elucidate the pathogenesis of diabetic peripheral neuropathy, the terminal part of peripheral nerve in the upper dermis was observed on electron microscopy using skin samples biopsied in 10 diabetics with symptomatic neuropathy and 6 age-matched controls. In diabetics, the density of nerve fibers was significantly lower than in controls. In addition, swelling, lytic change and vacuolation in the axon, multiplication of basement membrane of the Schwann cell and Schwann cell cluster devoid of axon were more frequently observed in diabetics. The Schwann cell did not show significant structural alterations. These findings suggest that the axon is primarily involved, at least in the terminal region of nerve fiber, in diabetic peripheral neuropathy. It is also concluded that the skin biopsy technique is harmless, cosmetically not troublesome and might be beneficial for studying peripheral neuropathies including diabetic neuropathy.

Ocular histopathologic studies of neonatal and childhood adrenoleukodystrophy

Histopathologic studies of the eyes of one patient (a boy who died at 14 years of age) with childhood adrenoleukodystrophy and two patients (girls who died at 24 and 31 months of age) with neonatal adrenoleukodystrophy showed the accumulation of the characteristic bileaflet inclusions in optic nerve macrophages, retinal neurons, and macrophages and loss of ganglion cell and nerve fiber layer. Additionally, in the two cases of neonatal adrenoleukodystrophy, changes resembling early retinitis pigmentosa were found, with accumulation of characteristic inclusions in the retinal pigment epithelium and pigment-laden macrophages. One of the patients with neonatal adrenoleukodystrophy also had an anterior subcapsular cataract and cystoid macular edema.

Adrenoleukodystrophy--its diverse CT appearances and an evolutive or phenotypic variant: the leukodystrophy without adrenal insufficiency

The CT appearance of adrenoleukodystrophy is discussed on the basis of 16 personal observations and a review of the literature. CT appearance was typical in 10 of the 16 cases, atypical but suggestive of adrenoleukodystrophy in four cases, and misleading in two cases. Atypical CT presentations were most often observed at an early phase of the disease and included unilateral lesions or lesions without opacification at the periphery of the edemalike areas after contrast enhancement. In three cases, neurological signs, CT scans, and conjunctival and skin biopsies were highly suggestive of adrenoleukodystrophy, but there was no adrenal insufficiency. These cases may correspond to an evolutive or phenotypic variant of adrenoleukodystrophy.

Inborn errors of metabolism

Inborn errors of metabolism often cause neurological dysfunction. These disorders are most common in childhood, but adult-onset forms with a different clinical presentation are encountered, examples being Pompe disease, Tay-Sachs disease, metachromatic leukodystrophy, Gaucher disease, and Maroteaux-Lamy disease. In the evaluation of a patient with a possible inborn error of metabolism, simple screening tests may aid in the diagnosis and provide direction for more comprehensive laboratory analysis. In most cases, diagnosis can be established without a brain biopsy through biochemical and ultrastructural analysis of peripheral tissues, blood, and urine. New clinical, genetic, and biochemical variants of inherited metabolic disorders are being recognized through wider application of screening tests, improved specificity of laboratory analysis, cell complementation experiments, and the identification of enzyme activator factors. Accurate diagnosis is important for medical management, determining prognosis, and genetic counseling.

Adrenomyeloneuropathy. A report on two families

Adrenomyeloneuropathy (AMN) is reported in two kindreds. In the first family, four male patients were affected: two adults with the full clinical picture but with a different chronology of the main symptoms, a third adult with central nervous system involvement and a child who died early with adrenal insufficiency. The second family included two male patients with AMN, one adult with raised ACTH levels and his nephew with normal adrenal function. Two other young males died with adrenoleukodystrophy (ALD), one being subjected to a postmortem study. Clinical, endocrinological, neurophysiological and pathological studies were performed. The following conclusions can be made (1) AMN and ALD are closely related entities; (2) there exists a considerable intrafamilial variability of the clinical picture; (3) AMN is to be included in the differential diagnosis of myelopathies and, conversely, signs of central nervous system damage must be sought in males patients with adrenal insufficiency; (4) electron microscopy of nerve twigs brings supportive diagnostic evidence pending the more widespread determination of the C26/C22 fatty acids ratios in cultured fibroblasts or plasma.

An ultramicroscopic study of skin and conjunctival biopsies in chronic neurological disorders of childhood

One hundred twenty-seven skin and 59 conjunctival biopsies were performed in 136 pediatric patients with chronic neurological disorders. Ultrastructural abnormalities were found in 48 of 72 patients with unequivocally progressive encephalopathies (67 of which could not be diagnosed by biochemical means) and in 4 patients with miscellaneous disease (fetal rubella syndrome and hereditary motor-sensory neuropathy), but in none of 55 patients with static or dubiously progressive encephalopathies. Of the 48 positive biopsies in the group with progressive encephalopathies, 39 showed abnormalities characteristic enough to permit a specific diagnosis (lysosomal storage disorders, neuroaxonal dystrophy, ophthalmoplegia-plus) in conjunction with a compatible clinical picture. In 9 cases no diagnosis could be made despite the finding of lamellar or vacuolar inclusions. In no case were discrepancies observed between the results of skin and conjunctival biopsies. Although biochemical analysis is the simplest and most effective technique for the diagnosis of most progressive encephalopathies, skin or conjunctival biopsy is a valuable procedure in patients without detectable enzyme deficiency.

Skin and conjunctival nerve biopsies in adrenoleukodystrophy and its variants

This study demonstrates that skin or conjunctival biopsies are capable of diagnosing adrenoleukodystrophy and its variants. Electron microscopy of cutaneous nerve twigs in eleven patients showed characteristic curved clefts and leaflets in Schwann cells surrounding myelinated axons. In addition, three conjunctival biopsies were done, two of which were positive. The two peripheral nerve trunk biopsies performed also showed characteristic Schwann cell changes.

Adrenomyeloneuropathy. A protracted, pseudosystematic variant of adrenoleukodystrophy

Histopathological, immunocytochemical, and electron microscopical investigations were carried out in a man with a protracted history of spastic paraparesis, adrenal insufficiency and hypogonadism. Pathological findings were identical with those of the few previously reported cases of adrenomyeloneuropathy (AMN) including cytoplasmic lamellar inclusions consisting of two parallel 2.5 nm leaflets separated by a clear space of variable extent, in the brain, spinal roots, adrenal gland, and interstitial cells of the testis. No inclusions could be found in oligodendrocytes. In brain macrophages they are thought to represent breakdown products of pathological myelin stored in lysosomes, whereas in other localizations they might be an expression of the primary metabolic defect of the cell. Special attention was paid to the pseudosystematic type of fiber tract degeneration in the spinal cord. The dying-back pattern of axonal destruction was interpreted as a possible result of the multisegmental demyelination observed in these tracts. All known hormones could be localized in the pituitary by immunocytochemistry. Corticotrophs and gonadotrophs were numerous. The structural damage of the adrenal cortex and the interstitial cells of the testis is, therefore, considered to result from the inborn error of metabolism on the one hand and from an enhanced stimulation exerted by ACTH and gonadotrophins on the other.

Electron microscopic examination of skin and conjunctival biopsy specimens in neuronal storage diseases

Skin and conjunctival biopsy specimens from fourteen patients with neuronal storage diseases were investigated using an electron microscope. The diseases were Tay-Sachs disease, ceroid-lipofuscinosis (Jansky-Bielschowsky type), Niemann-Pick disease (type B), highly suspected adrenoleukodystrophy, I-cell disease, mucolipidosis of the beta-galactosidase deficient type, Hurler disease, Hunter disease and Morquio disease. This examination provided valuable diagnostic information on some neuronal storage diseases but not on Morquio disease or highly suspected adrenoleukodystrophy. False negative results may sometimes occur using this examination method. However, this examination suggests the usefulness of skin and conjunctival biopsy specimens as a diagnostic tool in some neuronal storage diseases.

Adrenoleukodystrophy. Preliminary report of a connatal case. Light- and electron microscopical, immunohistochemical and biochemical findings

This is the first description of a connatal case of adrenoleukodystrophy. The clinical picture consisted of severe psychomotor retardation, convulsions and hypsarrhythmia, but no obvious signs of adrenal insufficiency. Pathologically, the adrenals were small. The entire cortex was largely replaced by large round cells. Ultrastructurally, some cells in the adrenal cortex contained inclusions with electron-lucent clefts surrounded by a membrane. The anterior pituitary lobe could be demonstrated to have produced ACTH. The central nervous system showed extensive zones of demyelination in the brainstem, the cerebellum and the right-sided capsula interna. In the demyelinated areas there was sudanophilic breakdown and an intense gliosis. Ongoing demyelination could also be demonstrated by the chemical analysis. In the gray matter there waere micropolygyria of the insular cortex and swollen nerve cells in the nucleus arcuatus. Ultrastructure revealed the type of inclusions in the microglia of the same type as in the adrenals, and a different type of inclusions in unidentifiable cells, possibly neurons. These latter inclusions consisted of loosely stacked lamellar material. The findings are interpreted as further evidence of storage taking place in this disease.

Diffuse cerebral sclerosis, melanoderma and adrenal insufficiency (adreno-leukodystrophy)

Two cases of adrenoleukodystrophy are described. The pathological picture was consistent with earlier observations about the disease with the difference that the brain tissue revealed material which stained metachromatically with toluidine blue and was insoluble in fat solvents.