New phenotypic variant of adrenoleukodystrophy. Pathologic, ultrastructural, and biochemical study in two brothers

ABCD1 and X-linked adrenoleukodystrophy: A disease with a markedly variable phenotype showing conserved neurobiology in animal models

X-linked adrenoleukodystrophy (X-ALD) is a phenotypically heterogeneous disorder involving defective peroxisomal β-oxidation of very long-chain fatty acids (VLCFAs), due to mutation in the ABCD1 gene. X-ALD is the most common peroxisomal inborn error of metabolism and confers a high degree of morbidity and mortality. Remarkably, a subset of patients exhibit a cerebral form with inflammatory invasion of the central nervous system and extensive demyelination, while in others only dying-back axonopathy or even isolated adrenal insufficiency is seen, without genotype-phenotype correlation. X-ALD's biochemical signature is marked elevation of VLCFAs in blood, a finding that has been utilized for massive newborn screening for early diagnosis. Investigational gene therapy approaches hold promises for improved outcomes. However, the pathophysiological mechanisms of the disease remain poorly understood, limiting investigation of targeted therapeutic options. Animal models for the disease recapitulate the biochemical signature of VLCFA accumulation and demonstrate mitochondrially generated reactive oxygen species, oxidative damage, increased glial death, and axonal damage. Most strikingly, however, cerebral invasion of leukocytes and demyelination were not observed in any animal model for X-ALD, reflecting upon pathological processes that are yet to be discovered. This review summarizes the current disease models in animals, the lessons learned from these models, and the gaps that remained to be filled in order to assist in therapeutic investigations for ALD.

Hepatic dysfunction in peroxisomal disorders

The peroxisomal compartment in hepatocytes hosts several essential metabolic conversions. These are defective in peroxisomal disorders that are either caused by failure to import the enzymes in the organelle or by mutations in the enzymes or in transporters needed to transfer the substrates across the peroxisomal membrane. Hepatic pathology is one of the cardinal features in disorders of peroxisome biogenesis and peroxisomal β-oxidation although it only rarely determines the clinical fate. In mouse models of these diseases liver pathologies also occur, although these are not always concordant with the human phenotype which might be due to differences in diet, expression of enzymes and backup mechanisms. Besides the morphological changes, we overview the impact of peroxisome malfunction on other cellular compartments including mitochondria and the ER. We further focus on the metabolic pathways that are affected such as bile acid formation, and dicarboxylic acid and branched chain fatty acid degradation. It appears that the association between deregulated metabolites and pathological events remains unclear.

Neonatal adrenoleukodystrophy: a clinical, pathologic, and biochemical study

Neonatal adrenoleukodystrophy constitutes a distinct genetic disorder of autosomal recessive inheritance, and is distinguishable from the cerebro-hepato-renal syndrome of Zellweger and X-linked juvenile adrenoleukodystrophy, although all three conditions store very long chain fatty acids. Abnormal clinical features in neonatal adrenoleukodystrophy are generally present at birth, and include muscle hypotonia, severe psychomotor retardation, and failure to thrive. These infants are generally blind and deaf, with seizures developing during their first few weeks. A retinopathic "leopard spot" is common, and should help identify this disorder. The brains of four infants who died of neonatal adrenoleukodystrophy were biochemically analyzed for complex lipids, including cholesterol, cholesterol esters, total phospholipids, total galactolipids, and gangliosides. Additional analyses included the separation and identification of very long chain fatty acids and various forms of brain plasmalogen. Analyses of brains with neonatal adrenoleukodystrophy revealed the chemical identification of at least two stored lipid products. Very long chain fatty acids are present, especially in cholesterol esters, and vinyl ether ethanolamine plasmalogens are markedly elevated. The storage of vinyl ether plasmalogen in brains of infants dying of neonatal adrenoleukodystrophy clearly distinguishes them from those with cerebro-hepato-renal syndrome of Zellweger, which fail to synthesize plasmalogens.

Cytomegalovirus-induced adrenal insufficiency in a renal transplant recipient

Cytomegalovirus (CMV) is an important pathogen in organ-transplant recipients. There have been frequent reports of CMV-induced adrenal insufficiency in patients with human immunodeficiency virus infection. Herein, we report CMV-induced renal insufficiency in a renal transplant recipient. A 24-year-old woman had gradual onset of weakness, anorexia, nausea, hypotension, and skin hyperpigmentation at 5 months after renal transplantation. The immunosuppression regimen included cyclosporine, mycophenolate mofetil, and corticosteroid (prednisolone, 5 mg/d). Recent history included acute CMV infection, which was treated with ganciclovir. Basal serum cortisol concentration was 4 microg/dL, and stimulated serum cortisol concentration was less than 10 microg/dL. All clinical signs and symptoms and hypotension gradually improved after the oral prednisolone dose was increased to 10 mg/d. Clinicians must be aware of the possibility of CMV-induced adrenal insufficiency in renal transplant recipients. The condition may be symptomatic despite low-dose prednisolone therapy.

Liver and chorion cytochemistry

Microscopic visualization of peroxisomes in chorionic villus cytotrophoblast and in biopsy and autopsy samples of liver and kidney, the presence of enlarged liver macrophages containing lipid droplets insoluble in acetone and n-hexane as well as polarizing inclusions formed by stacks of trilamellar sheets are of diagnostic value in peroxisomal disorders. Methods are presented for evaluating these structures by light microscopy; trilamellar inclusions are only detected by electron microscopy. Macrophage features are preserved in archival paraffin blocks. In adrenal cortex, insoluble lipid, polarizing inclusions and trilamellar structures should be looked for. The stains are easily reproducible, and all reagents are commercially available.

Neonatal seizures and severe hypotonia in a male infant suffering from a defect in peroxisomal beta-oxidation

In this paper, we describe a baby male born to healthy non-consanguineous parents presenting at birth with hypotonia and seizures. Additional salient clinical features included the development of glaucoma, the absence of significant facial dysmorphism and the absence of liver enlargement or renal cysts. The patient died at the age of 3 months. At autopsy, liver fibrosis and kidney glomerulosclerosis were noted. Neuropathological findings included pachygyria of the olivary nuclei and cerebellar neuronal heterotopias. There was no evidence for a demyelinating process. Biochemically, the patient was found to have elevated plasma levels of very-long-chain fatty acids (VLCFA) and abnormal bile acid intermediates, whereas other indicators of peroxisomal function (plasmalogen biosynthesis and plasma pipecolic acid) were normal. Catalase staining of a liver biopsy specimen revealed peroxisomes to be present in normal numbers, although some were abnormally large. Trilamellar inclusions typical of a peroxisomal fatty acid oxidation defect were present in macrophages. Indeed, beta-oxidation of the very-long-chain fatty acid hexacosanoic acid (C26:0) was found to be strongly deficient. Fatty acyl-CoA oxidase activity in the patient's liver was normal, however. Furthermore immunocytochemical studies using antibodies against acyl-CoA oxidase, bifunctional protein and peroxisomal thiolase, revealed the normal localization of all three enzyme proteins within the peroxisomes. We suggest that our patient has a selective peroxisomal beta-oxidation defect, a recently identified heterogeneous group of early-onset peroxisomal disorders distinct from the Zellweger syndrome and other generalized peroxisomal disorders.

Liver pathology and immunocytochemistry in congenital peroxisomal diseases: a review

Diagnostic and pathogenetic investigations of peroxisomal disorders should include the study of the macroscopic and microscopic pathology of the liver, in addition to careful clinical observations, skeletal X-ray and brain CT scan, assays of very long-chain fatty acids and bile acid intermediates, and selected enzyme activities. This review of the literature also contains novel observations about the following syndromes: cerebro-hepato-renal (Zellweger) syndrome, X-linked and neonatal adrenoleukodystrophies (ALD, NALD), NALD-like syndromes, infantile phytanic acid storage, classical Refsum disease, rhizomelic and other forms of chondrodysplasia punctata (XD, XR, AR), hyperpipecolic acidaemia, primary hyperoxaluria I, pseudo-Zellweger and Zellweger-like syndromes, and single enzyme deficiencies. Microscopic data include catalase staining and morphometry of peroxisomes, immunolocalization of beta-oxidation enzymes, detection of trilamellar, polarizing inclusions in PAS-positive macrophages, fibrosis and iron storage. Peroxisomal enlargement appears to be related to functional deficit in beta-oxidation disorders as well as in rhizomelic chondrodysplasia punctata. Because normal peroxisomal localization of active beta-oxidation enzymes can accompany a C26 beta-oxidation deficit, other mechanisms such as impaired transport of metabolites should be investigated. 'Ghost'-like organelles are shown in the liver of an infantile Refsum patient and in an NALD-like case; immuno-gold labelling of membrane proteins did not reveal ghosts in Zellweger livers.

Peroxisomal beta-oxidation defect with detectable peroxisomes: a case with neonatal onset and progressive course

A progressive demyelinating cerebral disorder is described in a normally-appearing female infant with neonatal seizures, progressive psychomotor deterioration, deafness, retinopathy, peripheral neuropathy and loss of myelin observed on magnetic resonance imaging (MRI) scanning. MRI also showed the absence of macroscopic neocortical dysplasia which is usually found in Zellweger syndrome (ZS). Adrenal cortical function was normal. The patient died at the age of 37 months. Extensive biochemical investigations of peroxisomal functions in the patient revealed an impairment of peroxisomal beta-oxidation resulting in elevated levels of very long (greater than C22) chain fatty acids in plasma and fibroblasts. Moreover, elevated plasma levels of intermediates of bile acid biosynthesis such as tri- and dihydroxycholestanoic acid were found. Other peroxisomal functions were normal. Immunoblotting of the peroxisomal beta-oxidation enzyme proteins in liver from the patient revealed normal responses with antisera against acyl-CoA oxidase, bifunctional protein and thiolase respectively. From these data we conclude that the patient had a deficiency of a single peroxisomal beta-oxidation enzyme at the level of either the bifunctional protein or peroxisomal thiolase with retained immunoreactivity against these enzymes.

The infant with nystagmus, normal appearing fundi, but an abnormal ERG

Many retinal disorders present during infancy with nystagmus, decreased vision, and normal-appearing fundi, but an abnormal ERG. The most common of these disorders are Leber's congenital amaurosis, achromatopsia, and congenital stationary night-blindness. Other disorders with similar ocular manifestations may be associated with a variety of life-threatening systemic abnormalities. This review describes the clinical, electrophysiological, and laboratory findings that can be used to distinguish among these conditions.

A pathological study of a peripheral nerve in a case of neonatal adrenoleukodystrophy

The pathological findings for a sural nerve biopsy specimen in a case of neonatal adrenoleukodystrophy are described. The density and total number of myelinated fibers in the patient showed no significant changes compared with controls. On electric microscopy, however, thickness of the myelin was smaller in the patient than in controls. Some linear or trilamellar inclusion bodies were found in Schwann cells and fibroblasts, similar to those found in X-linked adrenoleukodystrophy. Büngner's bands were also seen on electron microscopy, and myelin ovoids and balls were seen in teased fibers. These results show that a sural nerve biopsy is useful for the diagnosis of neonatal adrenoleukodystrophy. We suspect that axonal or neuronal degeneration occurs with changes in myelin in neonatal adrenoleukodystrophy.

An adult onset metachromatic leukodystrophy with dominant inheritance and normal arylsulphatase A levels

A family with a variant of adult onset metachromatic leukodystrophy is presented. Clinical details from three affected members are given. The neurophysiological and neuroradiological data on the two brothers who have been recently studied are included. One of these died and the post-mortem findings are discussed along with those from a cousin who died some years ago. Arylsulphatase A levels were normal in both brothers yet the histological findings in the one who died are of a metachromatic leukodystrophy and thin-layer chromatography confirms an excess of sulphatides in the white matter of his brain. Disabling hypotension was a striking feature in both brothers but adrenal function was shown to be intact and autonomic neuropathy seemed the likely cause. Study of the family suggests a dominant mode of inheritance.

Infantile Refsum's disease: a generalized peroxisomal disorder. Case report with postmortem examination

Infantile Refsum's disease (IRD) is a peroxisomal deficiency disease which is closely related to neonatal adrenoleukodystrophy (NALD) and the Zellweger syndrome (ZS). Recent observations suggest that NALD and ZS are separate genetic disorders but the delimitation towards IRD remains uncertain. We present here the first autopsy report of a patient who was clinically and biochemically diagnosed as having IRD, and we compare the findings with those from NALD and ZS. The main gross and microscopic findings comprised micronodular liver cirrhosis, small hypoplastic adrenals without degenerative changes, and large groups of lipid macrophages in liver, lymph nodes and certain areas of the cerebral white matter. The brain showed no malformations except for a severe hypoplasia of the cerebellar granule layer and ectopic location of the Purkinje cells in the molecular layer. A mild and diffuse reduction of axons and myelin was found in the corpus callosum and periventricular white matter, the corticospinal tracts, and the optic nerves. Large numbers of perivascular macrophages were present in the same areas but there was no active demyelination. The retina and cochlea showed severe degenerative changes. Peripheral nerves, skeletal system and kidneys were normal. Electron microscopy showed characteristic cytoplasmic inclusions with bilamellar profiles in macrophages in the liver, lymph nodes and brain but not in the adrenals. Similar inclusions were found in liver cells and astrocytes. The findings differ from ZS which shows cortical renal cysts, skeletal changes, liver changes, cerebral micropolygyria, neuronal heterotopias, and demyelination of the white matter. Cases with NALD show mild cerebral malformations, active demyelination, degenerative changes of the adrenals, liver changes, and bilamellar electromicroscopic inclusions in macrophages. Our cases thus resembled NALD but lacked active demyelination, cerebral cortical malformations and adrenal degenerative changes. Further autopsy studies will be necessary to determine whether these changes are consistent findings in IRD.

Hepatic peroxisomes in adrenoleukodystrophy and related syndromes: cytochemical and morphometric data

Peroxisomes were visualized by cytochemical staining for catalase or/and electron microscopy in liver biopsies of two boys with childhood adrenoleukodystrophy (ALD), and of two girls with autopsy confirmed neonatal adrenoleukodystrophy (NALD). In a third patient previously described as NALD, unusual organelles were seen which may be large abnormal microbodies. Enlarged peroxisomes (determined by morphometry) were also present in the livers of the other two NALD patients. In the ALD patient whose clinical disease was more severe, peroxisomes were larger than in the older ALD case. Catalase staining was diminished and markedly heterogeneous. Additional unusual features such as a separate population of tubular forms, contact with fat droplets, of tubular forms, contact with fat droplets, marginal plate and invaginations containing glycogen were seen in the neonatal cases. These data are compared to the enlarged or elongated peroxisomes and heterogeneous staining in the thiolase-deficient "pseudo-Zellweger" patient (Goldfischer et al. 1986) and in 2 siblings with acylCoA oxidase deficiency (Poll-Thé et al. 1986, 1988). Enlarged peroxisomes are a common feature in this group of patients with peroxisomal deficiency disorders, suggesting that increased size and lowered metabolic capacity are associated. Nevertheless a marked morphopathological heterogeneity of peroxisomes thus exists in syndromes described as NALD including previously published cases. Most likely this heterogeneity reflects different enzymatic deficiencies, as confirmed by the biochemical data available. Clinically similar syndromes cover divergent microscopical and enzymatic peroxisomal patterns, and naming of the disease should be adapted to reflect such data. Cytochemical studies are urged in every suspected patient.

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.

Short and long term influence of phenothiazines on liver peroxisomal fatty acid oxidation in rodents

Evidence is given that phenothiazines depress hepatic peroxisomal fatty acid oxidation in vivo. After oral administration to rats thioridazine and chlorpromazine inhibit peroxisomal beta-oxidation, evaluated by H2O2 production, during 2 weeks. In mice, this effect could not be demonstrated. However, in both species VLCFA are increased after short and long term drug administration. Electron microscopy reveals the presence of membranous structures in liver cytoplasm or lysosomes. The inhibition by thioridazine of peroxisomal beta-oxidation does not lead to hepatic peroxisome proliferation. The activities of enzymes related to fatty acid breakdown are not increased and liver peroxisomes are microscopically normal.

Infantile Refsum disease: an inherited peroxisomal disorder. Comparison with Zellweger syndrome and neonatal adrenoleukodystrophy

Three patients affected by infantile Refsum disease are described with mental retardation, minor facial dysmorphia, chorioretinopathy, sensorineural hearing deficit, hepatomegaly, failure to thrive and hypocholesterolaemia. Initially, only an accumulation of phytanic acid was thought to be present. More recent findings showed a biochemical profile very similar to that found in classical Zellweger syndrome or neonatal adrenoleukodystrophy. Morphologically typical peroxisomes were absent in the liver. All three disorders are associated with multiple peroxisomal dysfunction. Because of these similarities pertinent clinical data of our three patients are compared with those of reported patients diagnosed as having infantile Refsum disease, neonatal adrenoleukodystrophy or Zellweger syndrome who survived for several years. Attention is drawn to the difference in severity of clinical features, ranging from infantile Refsum's disease to neonatal adrenoleukodystrophy and, finally, to Zellweger syndrome.

Ocular pathologic findings in neonatal adrenoleukodystrophy

Ocular pathology in a case of neonatal adrenoleukodystrophy (ALD) showed marked degeneration of photoreceptor cells throughout the retina including the macula. Macroscopically visible white opacities in the cortical vitreous of the posterior fundus were shown immunohistochemically and ultrastructurally to be macrophages containing bileaflet inclusions, a finding previously unreported. Additional findings included extensive loss of the retinal nerve fiber and ganglion cell layers, optic nerve degeneration, and bileaflet inclusions in retinal pigment epithelial cells and macrophages of the retina and optic nerve. Focal retinal pigmentary changes were observed that histologically were different from retinitis pigmentosa.

Neonatal adrenoleukodystrophy. Impaired plasmalogen biosynthesis and peroxisomal beta-oxidation due to a deficiency of catalase-containing particles (peroxisomes) in cultured skin fibroblasts

Neonatal adrenoleukodystrophy belongs to the newly recognized group of inherited diseases, the peroxisomal disorders. Based on the reported similarities between neonatal adrenoleukodystrophy and the cerebro-hepato-renal (Zellweger) syndrome, we have studied peroxisomal functions in cultured skin fibroblasts from 5 neonatal adrenoleukodystrophy patients. The results indicate that multiple peroxisomal enzyme activities are deficient in fibroblasts from neonatal adrenoleukodystrophy patients. Digitonin titration experiments revealed that peroxisomes are strongly deficient in these fibroblasts as found earlier in fibroblasts from Zellweger patients. These findings not only explain the generalized loss of peroxisomal functions in neonatal adrenoleukodystrophy, but also provide an explanation for the observed resemblance in clinical and biochemical abnormalities between neonatal adrenoleukodystrophy and Zellweger syndrome. The implications for the pre- and postnatal detection of this disease will be discussed.

Neonatal adrenoleukodystrophy: new cases, biochemical studies, and differentiation from Zellweger and related peroxisomal polydystrophy syndromes

Eight new cases of autopsy-confirmed or suspected neonatal adrenoleukodystrophy (NALD) are presented together with new biochemical data on very-long-chain fatty acids (VLCFA) and plasmalogens and a review of all previously published cases. The clinical, biochemical, and histopathologic abnormalities characteristic of this newly recognized form of adrenoleukodystrophy are analyzed in detail and compared to the principal characteristics of the similar disorder, the cerebrohepatorenal syndrome of Zellweger (ZS). Using strict pathologic criteria for the diagnosis of NALD, we find that, despite many clinical resemblances, NALD and the ZS are distinguishable on the basis of histology and peroxisomal biochemistry. Patients with NALD demonstrate adrenal atrophy, systemic infiltration by abnormal lipid-laden macrophages, and elevations of saturated VLCFA. In contrast, patients with ZS have chondrodysplasia, glomerulocystic disease of the kidney, central nervous system dysmyelination, and elevations of unsaturated as well as saturated VLCFA, but they lack adrenal atrophy. We conclude that NALD and the ZS probably represent at least two different genetic defects.

Dysmorphic syndrome with phytanic acid oxidase deficiency, abnormal very long chain fatty acids, and pipecolic acidemia: studies in four children

We describe a relatively new syndrome in four children with characteristic facial dysmorphism, sensorineural hearing loss, severe visual impairment with retinitis pigmentosa, hypotonia, hepatomegaly, and severe developmental delay. Two patients had intracranial hemorrhage secondary to a vitamin K-responsive clotting defect; both had steatorrhea. Liver biopsy specimens in two children showed an accentuated lobular architecture with prominent fibrous bands in the portal area. In one, the ultrastructure showed accumulation of abnormal substances and occasional trilaminar structures in hepatocytes and other cells. All four patients had elevated serum phytanic acid concentrations (0.3 to 2.7 mg/dl, normal less than 0.2 mg/dl) and deficient fibroblast phytanic acid oxidase activity (0.1 to 6.7 pmol/mg protein/hr, normal 23 to 87 pmol/mg protein/hr). Serum pipecolic acid was 7 to 55 times normal, and the ratio of C26/C22 very long chain fatty acids was increased (0.10 to 0.22; normal less than 0.03). This characteristic syndrome has been described in several children and called infantile Refsum disease or phytanic acid storage disease. Its relationship to neonatal adrenoleukodystrophy, hyperpipecolic acidemia, and Zellweger syndrome is discussed.

Neonatal adrenoleukodystrophy

Nine cases of neonatal adrenoleukodystrophy are described. All patients had abnormal facial features, moderate to severe hypotonia, hepatomegaly, and retinitis pigmentosa. The clinical course was rapidly progressive in six cases and more protracted in three others. Biological signs of adrenal insufficiency were present in five cases. CT scan showed a demyelinating process in four patients. Trilamellar inclusions were found in the liver of four cases and dark and complex lipidic inclusions in three other cases. In the three necropsied patients there was severe alteration of the white matter involving particularly the cerebellum in two cases. Gyral and cytoarchitectonic disturbances were absent in all three cases. Increased plasma levels of very long chain fatty acids (8/8), phytanic acid (7/8) and bile fluid trihydroxycoprostanic acid (2/4) confirmed the deficiency of multiple peroxisomal enzymes. Clinical, histopathological and biochemical findings of these nine cases are compared to those reported in other neonatal adrenoleukodystrophy cases and to those of other neonatal peroxisomal disorders, that is cerebro-hepato-renal syndrome of Zellweger and infantile Refsum's disease.

Identification of the inflammatory cells in the central nervous system of patients with adrenoleukodystrophy

Adrenoleukodystrophy is a disorder of long-chain fatty acid metabolism associated with adrenal cortical insufficiency and central nervous system demyelination. The central nervous system disease is unusual in that it is abrupt in onset and accompanied by a considerable infiltration of mononuclear inflammatory cells. To determine the nature of these inflammatory cells, immunocytochemical staining was carried out on the mononuclear cells in the brain and cerebrospinal fluid of patients with adrenoleukodystrophy. Monoclonal antibodies to T lymphocytes (T11), the helper/inducer (T4) and cytotoxic/suppressor (T8) subsets of T lymphocytes, B lymphocytes (B1), and monocyte/macrophages (M1 or esterase) were used. Mononuclear cells in the perivascular cuffs of autopsy material from 4 patients were, on average, 59% T cells, 34% T4 cells, 16% T8 cells, 24% B cells, and 11% monocyte/macrophages. Cerebrospinal fluid from 8 of 10 patients had increased IgG concentrations. Mononuclear cells in the cerebrospinal fluid of 6 patients with active disease were, on average, 61% T cells, 40% T4 cells, 16% T8 cells, 3% B cells, and 18% monocyte/macrophages. This distribution of cells is similar to that found in the central nervous system during a cellular immune response and suggests the possibility that one component of this disease is immunologically mediated.

A milder variant of Zellweger syndrome

A 4.5-year-old male patient is described with chorioretinopathy, minor facial anomalies, delayed closure of the fontanel, mental retardation, moderate hypotonia, epilepsy and hepatic fibrosis. Postural control, intentional vocalising and manual dexterity were superior to the performance of patients with classical Zellweger syndrome (ZS). Morphologically distinct peroxisomes were absent in the liver. In blood elevated pipecolic acid levels and abnormal levels of bile acid intermediates were found. The plasmalogen content of erythrocytes was normal. In fibroblasts we found an accumulation of very long chain fatty acids, decreased activity of acyl CoA:dihydroxyacetone phosphate acyltransferase, and impaired de novo biosynthesis of plasmalogens. On the basis of these clinical, ultrastructural and biochemical characteristics we assume that this patient represents a milder variant of the classical cerebro-hepato-renal syndrome of Zellweger.

Adrenomyeloneuropathy: report of a family and electron microscopical findings in peripheral nerve

A family with adrenomyeloneuropathy (AMN) is reported, whose female carriers showed severe neurological and biochemical abnormalities. Cytoplasmic lamellar inclusions were found in endoneurial cells of the biopsied sural nerve of a male patient. In spite of the peripheral nervous system involvement in patients with AMN, there have been few reports of these inclusions in the peripheral nerves of such cases.

Peroxisomal defects in neonatal-onset and X-linked adrenoleukodystrophies

Accumulation of very long chain fatty acids in X-linked and neonatal forms of adrenoleukodystrophy (ALD) appears to be a consequence of deficient peroxisomal oxidation of very long chain fatty acids. Peroxisomes were readily identified in liver biopsies taken from a patient having the X-linked disorder. However, in liver biopsies from a patient having neonatal-onset ALD, hepatocellular peroxisomes were greatly reduced in size and number, and sedimentable catalase was markedly diminished. The presence of increased concentrations of serum pipecolic acid and the bile acid intermediate, trihydroxycoprostanic acid, in the neonatal ALD patient are associated with a generalized diminution of peroxisomal activities that was not observed in the patient with X-linked ALD.

Disturbed very long chain (C24-C26) fatty acid pattern in fibroblasts of patients with Zellweger's syndrome

The very long chain fatty acids in cultured fibroblasts from six patients with the cerebro-hepato-renal syndrome of Zellweger, from six of their parents, from three controls, and also in three amniotic fluid control cell lines were analysed by gas chromatography. Increased concentrations of hexacosanoic acid (C26:O) were consistently found in the Zellweger syndrome. Also the ratios C26:O/C22:O, C25:O/C22:O, and C24:O/C22:O were elevated. The very long chain fatty acid levels and ratios in fibroblasts from the patients' parents were within the normal range. Findings in amniotic fluid cell lines indicate the possibility of antenatal diagnosis for Zellweger's syndrome. The similarities between neonatal adrenoleukodystrophy and Zellweger's syndrome suggest the applicability of this technique also in neonatal adrenoleukodystrophy.

Electrophysiologic studies in neonatal adrenoleukodystrophy

Recent electrophysiologic studies have focussed attention on the X-linked adrenoleukodystrophy (ALD) and its myeloneuropathic variant. No organized studies are, however, yet available on its relatively recently described neonatal variant. We conducted electroencephalographic, electroretinographic and evoked response studies in 2 patients with neonatal ALD. In one patient, an infant, initial EEG, hypsarrhythmic in waking and somewhat periodic in sleep, showed dramatic improvement on ACTH therapy accompanied with a seizure-free status. The EEG and clinical improvement, however, were temporary. No improvement occurred following pyridoxine therapy. Her electroretinogram (ERG), visual evoked responses (VERs) and far-field short latency brain-stem auditory evoked responses were also abnormal. The latter studies probably reflected photoreceptor degeneration, optic nerve involvement, cochlear and/or auditory nerve involvement respectively in neonatal ALD. The other patient, a 3.5-year-old girl, also had an EEG characterized by a moderate- to high-amplitude slow background activity and high-amplitude multifocal, generalized or periodic paroxysmal discharges, but presence of some better formed theta frequencies in background activity precluded a hypsarrhythmic label on her EEG. Her ERGs and VERs were totally extinct but in contrast to the first patient, she had clear-cut optic atrophy and retinitis pigmentosa on ophthalmological examination.

Adrenoleukodystrophy: survey of 303 cases: biochemistry, diagnosis, and therapy

Adrenoleukodystrophy (ALD) is a genetically determined disorder associated with progressive central demyelination and adrenal cortical insufficiency. All affected persons show increased levels of saturated unbranched very-long-chain fatty acids, particularly hexacosanoate (C26:0), because of impaired capacity to degrade these acids. This degradation normally takes place in a subcellular organelle called the peroxisome, and ALD, together with Zellweger's cerebrohepatorenal syndrome, is now considered to belong to the newly formed category of peroxisomal disorders. Biochemical assays permit prenatal diagnosis, as well as identification of most heterozygotes. We have identified 303 patients with ALD in 217 kindreds. These patients show a wide phenotypic variation. Sixty percent of patients had childhood ALD and 17% adrenomyeloneuropathy, both of which are X-linked, with the gene mapped to Xq28. Neonatal ALD, a distinct entity with autosomal recessive inheritance and points of resemblance to Zellweger's syndrome, accounted for 7% of the cases. Although excess C26:0 in the brain of patients with ALD is partially of dietary origin, dietary C26:0 restriction did not produce clear benefit. Bone marrow transplant lowered the plasma C26:0 level but failed to arrest neurological progression.

Adrenoleukodystrophy: clinical, pathological and biochemical findings in two brothers with the onset of cerebral disease in adult life

Two brothers are described in whom adrenoleukodystrophy (ALD) presented as progressive cerebral degeneration in early adult life. Diagnosis during the life of one brother was based on cerebral biopsy appearances. At autopsy there was a leucodystrophy and an additional myelopathy in both cases. Biochemical studies carried out on the propositi and other family members revealed characteristic abnormalities of ALD in the propositi and two, as yet clinically unaffected, adult brothers, and abnormalities characteristic of the heterozygous state in their mother. Neither of the clinically affected brothers showed clinical features of hypoadrenalism and these cases emphasize the importance of considering the diagnosis of ALD in adult males with leucodystrophy even in the absence of overt adrenal insufficiency.

Adrenomyeloneuropathy--clinical and biochemical diagnosis

Adrenomyeloneuropathy (AMN) is an X-linked storage disease of very-long-chain fatty acids that presents as primary adrenocortical failure combined with spastic paraparesis and peripheral neuropathy. This disorder was diagnosed in three unrelated adult males. Definitive diagnosis was made by finding elevated very-long-chain fatty acids in plasma and skin biopsy samples. Biochemical characterisation of this disease has elucidated its genetics, clarified its relationship with adrenoleukodystrophy of children and other phenotypic variants, and allowed heterozygote identification, accurate genetic counselling and prenatal diagnosis.

Ocular histopathologic and biochemical studies of the cerebrohepatorenal syndrome (Zellweger's syndrome) and its relationship to neonatal adrenoleukodystrophy

The eyes of three infants with cerebrohepatorenal disease (Zellweger's syndrome) who died demonstrated ganglion cell loss, gliosis of the nerve fiber layer and optic nerve, optic atrophy, and changes resembling those of retinitis pigmentosa in the retina and pigment epithelium. Ultrastructural examination showed bileaflet inclusions identical to those seen in neonatal adrenoleukodystrophy in the pigment epithelium and in pigmented macrophages, but these were absent in the cornea. Biochemical analysis of tissues demonstrated an excessive amount of very-long-chain fatty acids in the ocular tissues, an abnormality also found in adrenoleukodystrophy. These histopathologic and biochemical results demonstrated that the cerebrohepatorenal syndrome and neonatal adrenoleukodystrophy are similar in regard to ocular abnormalities and the presence of saturated very-long-chain fatty acids.

Angulate lysosomes

Under many circumstances, macrophages accumulate lipids (possibly in combination with other materials) in the form of micelles that by their rigidity and size impart an irregular, angulate shape to the lysosomes in which they are stored. When macrophages contain large numbers of these angulate lysosomes, they have a characteristic light microscopic appearance and are often designated Gaucher cells or Gaucher-like cells. In most instances, however, the angulate lysosomes are small in number or size and are not easily recognized by light microscopy. A search of the literature and our own files revealed angulate lysosomes in a considerable number of conditions in which they have not previously been observed or recognized. In most conditions, the evidence indicates that the material stored is derived from phagocytosed cells that are incompletely digested, either because they are simply too numerous to be handled by the macrophage or due to a primary metabolic deficiency, or both. In contrast to what has been assumed, angulate lysosomes not only arise in situations in which blood cells are phagocytosed, but also when various types of degenerating tumor cells, remnants of myelin sheaths, or bacteria accumulate inside macrophages. In yet other conditions, the origin of the lysosomal contents remains to be elucidated.

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.

Striated adrenocortical cells in cerebro-hepato-renal (Zellweger) syndrome

Adrenal glands from eight patients with the cerebro-hepato-renal syndrome, a disease in which there are no morphologically demonstrable peroxisomes, were studied histologically; one of the eight was also examined ultrastructurally. Seven of the eight demonstrated striated adrenocortical cells in the inner portion of the adrenal cortex. Ultrastructural examination confirmed that the striated cells contained the lammellae and lamellar-lipid profiles of very long chain fatty acids-cholesterol esters that are characteristic of adreno-leukodystrophy. This morphologic observation further emphasizes the common pathogenetic features of the cerebro-hepato-renal (Zellweger) syndrome and adreno-leukodystrophy.

Adrenoleukodystrophy

Adrenoleukodystrophy (ALD) is an X-linked degenerative disease characterized by progressive demyelination and adrenal insufficiency. Several phenotypes are described. In post-mortem tissues there is an accumulation of saturated or mono-unsaturated very long chain fattyacids (VLCFA) in the cholesterol ester fraction of adrenal cortex and cerebral white matter. The accumulated fatty acids are unbranched with carbon chain length between 23 and 32 with most containing 25 or 26 carbons. Determination of VLCFA in readily accessible tissues such as skin fibroblasts and plasma allows for reliable detection of patients and carriers.

Neonatal-onset adrenoleukodystrophy in a girl

A 4-year 11-month-old girl developed cerebral degeneration with onset in the neonatal period. Postmortem examination showed gross, microscopic, ultrastructural, and biochemical changes identical to those associated with adrenoleukodystrophy (ALD), a sex-linked disorder of boys beginning in the first decade of life. Cytoplasmic inclusions ultrastructurally identical to those in brains and adrenal glands of ALD patients were present not only in this girl's adrenal glands and brain but also in reticuloendothelial cells of the liver, lymph node, spleen, thymus, and hepatic lysosomes. Thin-layer and gas-liquid chromatographic analysis of cerebral tissues demonstrated abnormal long-chain fatty acids in the cholesterol ester fraction, identical to those present in affected tissues of males with ALD. The documentation of abnormal long-chain fatty acids in cerebral tissues of a female patient supports the concept that infantile-onset ALD is a clinically and pathologically distinctive entity characterized by prominent visceral storage abnormalities and occurrence in both sexes. These findings also suggest that ALD and related entities are either phenotypic variants of a specific enzyme deficiency or separate disease resulting from different mutations in a common metabolic pathway.

A case of adrenoleukodystrophy in a girl. Genetic considerations

We report the case of a girl who developed leukoencephalopathy and adrenal atrophy and died at 3 years of age. Histologically, demyelination, gliosis, perivascular lymphocytic cuffing and sudanophilia were present in the brain. The adrenal cortex was atrophic. Ultrastructurally, there were numerous cytoplasmic inclusions in brain macrophages, consisting of two leaflets separated by an intervening space of variable low electron density. Brain tissue cholesterol esters contained a high proportion of long chain fatty acids. The findings are discussed and compared with those in the literature. Emphasis is placed on the fact that the disease occurred in a girl in apparent contradiction to the commonly accepted X-linked hereditary transmission of adrenoleukodystrophy. Some possible genetic explanations for our case are put forward.

Accumulation of very long chain fatty acids is common to 3 variants of adrenoleukodystrophy (ALD). "Classical" ALD, atypical ALD (female patient) and adrenomyeloneuropathy

Fatty acids of cholesterol esters were analyzed by gas chromatography in affected CNS white matter of 3 variants of ALD ("classical" ALD, atypical ALD (adult female) and AMN) and of 10 controls with myelin breakdown of an etiology other than ALD. In all 3 ALD variants a marked accumulation of very long chain fatty acids (VLFA) as compared to control material was observed. This was due to the accumulation mainly of saturated C24-C32 fatty acids, particularly of C26:0, C25:0 and, to a lesser extent, C24:0 and C27:0 fatty acids. Our results demonstrate for the first time an accumulation of VLFA in an adult female patient (atypical ALD), who probably is an ALD heterozygote rather than a variant of AMN, and confirm and extend earlier findings in classical ALD and AMN, respectively. It appears that ALD may be a single nosological entity with clinically and morphologically different variants sharing specific ultrastructural (accumulation of paired leaflets) and neuro-biochemical (accumulation of VLFA) diagnostic markers.

Morphology and distribution of cytoplasmic inclusions in adrenoleukodystrophy

We report some additional observations on the pathognomonic cytoplasmic inclusions in a typical case of adrenoleukodystrophy (ALD). Study of the linear inclusions by means of tilt-stage electron microscopy indicated that they represent trilaminar sheet-like structures distinct from materials seen in various other storage disorders. This study emphasizes that the inclusions in the adrenal and testicular parenchymal cells morphologically differ from those in the brain macrophages. In the latter they occur as membrane-bound discrete structures while in the parenchymal cells they are always seen lying free in the cytoplasm and associated with cleft-like spaces. This morphologic variation of the inclusions is noteworthy and probably reflects a biochemical difference in the storage materials in these two most severely affected organs. In addition, this study demonstrates the presence of linear inclusions within macrophages in otherwise normal-appearing liver, spleen, thymus and also in the renal tubular cells. These findings suggest that the abnormal materials containing very long chain fatty acids enter the blood stream and become sequestered in the reticuloendothelial system and possibly are also excreted in the urine. Detection of these abnormal fatty acids in blood and urine may simplify diagnosis of ALD.