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The composition and distribution of steryl esters in human diseased or developing brain tissue has been studied. The abnormal brain conditions included sudanophilic leukodystrophy, multiple sclerosis plaque, subacute sclerosing panencephalitis, and an old cerebral infarction and two types of brain-derived tumors. In addition to the above abnormal tissue, steryl esters were also examined in developing and normal adult human brain. It was found upon subcellular fractionation that the steryl ester was localized mainly in the soluble nonparticulate material. A cholesteryl ester-rich fraction, floating on top of distilled water after centrifugation, was recovered only in the developing brain or in instances where there was myelin damage. The sterol portion of the steryl ester was largely cholesterol. The fatty acid moiety was mainly composed of C(16), C(18), and C(20) fatty acids. The dominant fatty acid was oleic acid, and the proportion of this fatty acid increased in demyelination. Although there were great differences in the quantities of steryl ester found, the fatty acid profiles of normal developing and adult brain were quite similar. As has been noted by others, the fatty acid composition of brain steryl esters most closely resembles that of brain phosphatidylcholine.

The livers of four patients with metachromatic leukodystrophy contained galactosyl sulfatide and lactosyl sulfatide, whereas these substances were undetectable in normal human liver. On the basis of methanolysis and permethylation studies, both sulfatides were shown to be substituted with sulfate at the C-3 position of the galactose moiety. Examination of the fatty acid compositions of these sulfatides showed that C(22:0) and higher 2-hydroxy and nonhydroxy fatty acids predominated in both. Both sulfatides contained the same long-chain bases, predominantly sphingosine, dihydrosphingosine, and phytosphingosine. Using as criteria the proportion of lactosyl sulfatide to galactosyl sulfatide, and the fatty acid and long-chain base compositions, the liver sulfatides from subjects with metachromatic leukodystrophy closely resemble those in the kidney and differ from those in brain and peripheral nerve.

Liver specimens of dogs affected with the canine form of globoid cell leukodystrophy were assayed for activities of specific glycosphingolipid β-galactosidases. As in the human disease, activities of galactosylceramide and galactosylsphingosine β-galactosidases were deficient in three homozygous affected dogs, while lactosylceramide, Gm1-ganglioside and asialo Gm1-ganglioside β-galactosidases were normal. Upon electrofocusing, the livers of the affected dogs totally lacked the normal major galactosylceramide β-galactosidase peak at an isoelectric point of 5.4 to 5.5 and the minor peak at pH 5.8 to 6.0. A suspected carrier dog showed an intermediate activity of the major enzyme peak. However, another peak of galactosylceramide β-galactosidase at pH 5.0 to 5.1 was relatively preserved in the affected dogs, and it was only slightly less than normal in the carrier dog. Corresponding to these findings, the sharp peak at pH 5.4 to 5.5 of 4-methylumbelliferyl β-galactosidase was almost absent in affected dogs and was partially deficient in the heterozygous dog, while other two peaks were normal. Electrofocusing patterns of lactosylceramide and asialo Gm1-ganglioside β-galactosidases were completely normal in affected dogs. The peak of 4-methylumbelliferyl β-galactosidase at pH 5.4 to 5.5 was not associated with the latter two sphingolipid β-galactosidase activities. Therefore, the 4-methylumbelliferyl β-galactosidase peak at pH 5.4 to 5.5 appears to represent one of the two major components of galactosylceramide β-galactosidase, which is primarily defective in the canine form of globoid cell leukodystrophy. The human and canine forms of the disease can be considered equivalent to the extent that both are caused by genetic deficiency of galactosylceramide and galactosylsphingosine β-galactosidases, but they are clearly different in the nature of the mutations underlying the defective enzymes.

Activity of lactosyl ceramide β-galactosidase (β-D-galactoside galactohydrolase, EC 3.2.1.23) was found to be extremely low in enzyme preparations from liver, brain, and cultured skin fibroblasts from patients with Krabbe's disease. Leukocytes from one set of parents had enzyme levels approximately half those measured in control leukocytes. The low activity observed for this galactolipid hydrolase is the fourth enzymatic deficiency noted for this genetic disease. Beta-galactosidase activity toward galactocerebroside, psychosine, and monogalactosyl diglyceride is also low in patients with Krabbe's disease. Other lysosomal enzymes measured were found to be in the normal range. This enzymatic defect may provide a better explanation for the pathological and chemical findings previously reported for this syndrome.

Specific glycosphingolipid β-galactosidases in normal human liver were investigated using radioactively labeled galactosylceramide, lactosylceramide, Gm1-ganglioside, and asialo Gm1-ganglioside as substrates. Chloride ion was required for full stimulation and stabilization of these reactions. Taurocholate was the most effective stimulator, except for Gm1-ganglioside β-galactosidase which did not appear to be affected by any of the detergents tested. Electrofocusing of the 10,000 x g supernatant of sonicated, frozen-thawed water homogenates gave three consistent peaks of nonspecific 4-methylumbelliferyl β-galactosidase activities. Their isoelectric points were pH 4.1 to 4.2 (α), 4.5 to 4.6 (β), and 4.8 to 4.9 (γ). All of the three peaks contained activities of lactosylceramide and asialo Gm1-ganglioside β-galactosidases, but the activities of galactosylceramide and Gm1-ganglioside β-galactosidases were present only in the β and γ peaks. Gel filtration with Sephadex G-200 separated activities of 4-methylumbelliferyl β-galactosidase into three peaks. When each of the gel filtration peaks was subjected to electrofocusing, the second gel filtration peak corresponded to the β peak, and the third peak to the γ peak, respectively. The first gel filtration peak, however, gave inconsistent results in electrofocusing, always giving a single peak but with varying isoelectric points. The primary purpose of this study was to establish the optimal assay conditions for these enzymes in whole tissues and to obtain a reproducible fractionation procedure, without sacrificing the recovery of total activities. These were the criteria necessary for the subsequent studies of disorders in which specific glycosphingolipid β-galactosidases are genetically deficient.

Two cases of a peculiar progressive encephalopathy clinically resembling a leukodystrophy, occurring in siblings, are reported. In both cases there was diffuse involvement of the white matter, with necrosis and vascular proliferation, the histological picture being similar to that observed in subacute necrotizing encephalomyelopathy. All grey structures were normal, except for a slight spongiosis of the locus niger in both cases.

The presence and significance of intranuclear bodies in astrocytes and vacuoles delimited by a single membrane in neurones and nucleolar changes are described in two cases of leukodystrophy.

This is the sixth report of a disease first described by Alexander in 1949. 1 Several names have been given to this cerebral disorder (Table), but the eponym "Alexander's disease" will be used herein. The main neuropathological characteristic was granular, eosinophilic deposits at all interfaces of the central nervous system; that is, in the perivascular tissue and at the pial surface. Five of the cases were also characterized by megalencephaly, leukodystrophy, and an onset of the disease shortly after birth followed by death in a few years (Table). Clinical History The present case pertains to a boy who died at age 22 months. No instances of epilepsy or nervous disorders were known in the family. The prenatal history and birth were normal, except for a slight toxemia during pregnancy. The disease started at 41/2 months, allegedly subsequent to immunization with poliomyelitis vaccine, when the child experienced high fever and convulsions.

A variety of peripheral nerves were studied by light microscopy from 7 young Cairn Terrier dogs which were necropsied and histologically diagnosed as having canine globoid-cell leukodystrophy (Krabbe's type). All nerves examined had severe degenerative changes in axons and myelin sheaths, similar to lesions in human cases of Krabbe's disease. Endoneurial fibrosis was not prominent but many PAS positive macrophages and a mode-rate number of mast cells were in the endoneurium. However, the dorsal root ganglia had no detectable changes in neurons nor proliferation of capsule cells or interstitial cells. Myopathy in the form of muscle atrophy and degeneration of muscle nuclei was seen in two dogs. Thus, in canine globoid-cell leukodystrophy, lesions occur widespread in the peripheral as well as in the central nervous system.

Increasing interest isnowbeingpaidtoacorrect diagnosis intheearly stages ofthedifferent types of degenerative diseases ofthecentral nervous system ofinfancy andchildhood. Amongthediseases which affect thewhite matter ofthenervous system asubgroupisrecognized astheheredo-degenerative type ortheleucodystrophies. In1956Poserandvan Bogaert (1956) stated thatitwasalmost imposslble tomakeaclinical diagnosis oftheleucodystrophies unless there wasawell-documented family history. However, bythedemonstration ofacharacteristic sulphatide pattern ofurinary sediment lipids by paperchromatography themetachromatic typeof leucodystrophy (sulphatidosis) cannowbediagnosed duringlife(Hagberg and Svennerholm, 1960; Hagberg, Sourander, andSvennerholm 1961). It canalso bediagnosed through thedemonstration of brownmetachromatic granular deposits inperipheral nervebiopsy specimens (Thieffry andLyon,1959; Hagberg, Sourander, andThoren, 1962). Inthe other important typeofleucodystrophy, thegloboid cell typeofKrabbe's disease, nocharacteristic clinical laboratory tests havehitherto beendescribed. However, diagnostic help canbeobtained fromanalysis oftheproteins ofthecerebrospinal fluid. Thiswill beshowninsixwell-documented cases ofKrabbe's disease.

— —Three cases of “Krabbe Type” globoid cell leukodystrophy are described in young Cairn Terriers, which were from three different litters out of the same dam, and with father and son as sires. The pedigree of both parents also revealed a common ancestral relationship several generations removed. The gross and histological lesions are described and comparisons are made with the condition in man. Several criteria are listed to aid in the antemortem diagnosis of this disease in dogs. Resume— —Trois cas de leucodystrophie de cellules globoides de “Type Krabbe” sont decrits dans de jeunes terriers Cairn, qui provenaient de trois litieres differentes de la meme mere, avec le pere et le fils comme peres. Le pedigre des deux parents revela un rapport ancestral commun remontant a plusieurs generations. Les lesions sommaires et histologiques sont decrites et des comparaisons sont etablies par rapport a des etats dans l'homme. Plusieurs criteres sont enumeres pour aider a l‘etablissement d'un diagnostic avant la mort dans le cas de cette maladie chez les chiens. Zusammenfassung— —Drei Falle von “Krabben Typus” globoidzelliger Leukodystrophie bei jungen Cairn Terriers werden beschrieben, welche letzteren aus drei verschiedenen Wurfen ein-und derselben Hundin stammten, wobei Vater und Sohn als Zuchttiere dienten. Der Zuchtstamm beider Eltern zeigte gleichfalls eine gemeinschaftliche Abstammungsverwandschaft bei mehreren, fruheren Generationen. Die allgemeinen und histologischen Veranderungen werden beschrieben und Vergleiche mit solchen Zustanden bei Menschen gemacht. Mehrere Kriterien werden zur Unterstutzung der antemortem Diagnose dieser Hundekrankheit aufgezeichnet.

The finding of tubular cytoplasmic inclusions in renal and skin endothelium of patients with SLE is confirmed. Similar inclusions were seen in a lymph node of a patient with SLE, focal and diffuse glomerulonephritis, Krabbe leukodystrophy and Coxsackie myocarditis. Although the inclusion resembles paramyxovirus nucleoprotein, definite proof of its viral nature is lacking. The hypothesis that the inclusion is a manifestation of cellular injury is supported by its occurrence in such a variety of unrelated conditions. It remains to be determined whether the prevalence of the inclusion or the frequency with which it is found in tissues from patients with SLE may be of diagnostic significance.

Fibroblasts cultured from skin biopsies obtained from patients with inherited storage diseases exhibited the specific lysosomal hydrolase deficiency found in the patient's tissues. Combined thin layer and gas liquid chromatography of the glycosphingolipids isolated from such fibroblasts showed variations in the concentration of the seven glycosphingolipids found in normal fibroblasts, GL-1a, GL-1b, GL-2a, GL-3, GL-4, Gm3, and Gd3. In three diseases in which visceral accumulation of glycosphingolipid has been demonstrated, namely, Fabry's disease, lactosylceramidosis and Gaucher's disease, two to 4-fold elevations of the glycosphingolipids, GL-3, GL-2a, and GL-1a, respectively, were found in the cultured skin fibroblasts. Tracer studies with d-[U-14C]glucose demonstrated negligible catabolism of GL-3 in Fabry cells and GL-1a in Gaucher cells. The rate of synthesis and degradation of other glycosphingolipids appeared normal with the exception of GL-2a which was virtually absent from Fabry fibroblasts. Although the enzyme deficiencies characteristic of ganglioside storage (neuronal) diseases could be demonstrated in fibroblasts, Gm1 ganglioside could not be detected in two strains of fibroblasts from patients with Gm1-gangliosidosis type I. However, in two strains of fibroblasts from patients with Gm2-gangliosidosis type I (Tay-Sachs disease) there was some evidence for the presence of Gm2 and its asialo derivative. Fibroblasts from patients with inherited lipidoses which primarily affect the myelin sheath, such as globoid cell leukodystrophy and metachromatic leukodystrophy did not accumulate cerebroside (GL-1b) or sulfatide (GL-1bS) despite the fact that the specific enzyme deficiency could be readily demonstrated. The addition of large amounts of sulfatide to the medium caused storage of sulfatide in normal skin fibroblasts which was rapidly metabolized when the cells were returned to normal medium. In contrast, fibroblasts from patients with metachromatic leukodystrophy (with deficient arylsulfatase A activity) ingest but do not metabolize exogenous sulfatide. A marked abnormality of Gm3 and Gd3 catabolism was demonstrated in fibroblasts from three patients with I-cell disease, an unusual genetic disorder in which there is a generalized lysosomal hydrolase deficiency.

Myelin was isolated from the brain of a patient with Krabbe's globoid cell leukodystrophy at 0.4% of the normal yield. Despite the exceedingly low yield, the fraction appeared morphologically clean, and consisted mostly of well-preserved myelin lamellae and few contaminating structures. Total lipid and cholesterol were slightly lower than in normal myelin. Total phospholipid was normal, but the ratio of ethanolamine phospholipid to lecithin was reversed. Total galactolipid was normal, and consisted only of cerebroside and sulfatide in normal proportions. The only sugar in cerebroside and sulfatide was galactose. The fatty acid composition of cerebroside and sulfatide was essentially normal with no deficiency of long-chain fatty acids and only with a reversed ratio of C(24:0) to C(24:1) in cerebroside. These data appear to exclude the previous postulate that abnormally rapid breakdown of myelin occurs in this disorder as the result of the formation of chemically abnormal myelin, deficient in sulfatide.

In 4 cases of MS, in which the progression of disease differed, and in one case of infantile OLD the proteins of a homogenate and a myelin fraction with and without plaques were separated electrophoretically with polyacrylamide gels in a buffer system of phenol/formic acid/water. The relation of proteolipid protein to basic protein was estimated planimetrically and compared with control cases. In myelin from plaque material of chronic running MS cases an average decrease of 41% in basic protein was observed, while in an acute progressing case no obvious alterations could be discerned. Myelin from apparently normal MS white matter showed an average decrease of 13% in basic protein. The results of the OLD case were similar to those obtained from the chronic MS cases. The decrease of basic protein (chronic MS, OLD) was markedly more in the homogenate fraction than in the purified myelin. In a control case with autolytic alterations (autopsy after 24 hours) the content of basic protein was also diminished. Our findings indicate that the reduction of basic protein in myelin is a non-specific effect in demyelinating diseases.

Neuronal perikarya of normal and myelin deficient Jimpy mice were isolated with gradient centrifugation techniques, and analyzed for chemical composition and capacity to synthesize sulfatide: (1) Normal neurons contain small but significant amounts of sulfatide. (2) After intraperitoneal injection of Na235SO4, labeled sulfatide appears rapidly in neurons in vivo. (3) Cerebroside sulfotransferase, the enzyme involved in the last step of sulfatide biosynthesis, is active in normal neurons in vitro. (4) Jimpy neurons have a capacity to synthesize sulfatide of about 14% of normal in vivo, and of about 24% of normalin vitro. While the physiological importance of sulfatide, an acidic lipid, for the function of the neurons remains unknown, the study shows that in the Jimpy leukodystrophy not only the metabolism of myelin, but also that of neurons, is disturbed.

Peculiar filamentary deposits, present diffusely and abundantly throughout the central nervous system of a child with a leukodystrophy, raised the following considerations about their origin and concerning the pathogenesis of the disease process

The first in utero diagnosis of globoid cell leukodystrophy was made by assaying the activity of galactocerebroside β-galactosidase in cultured amniotic fluid cells from a fetus at risk. The enzyme activity was approximately 5% of control levels. Galactocerebroside β-galactosidase activities in brain and liver tissue obtained from the aborted fetus were 1% or less of control tissues, confirming the diagnosis.

1. Die Hirnsklerosen infolge spezifischer selbstandiger Entmarkung bilden die diffuse Skleroseim engeren Sinne. Sie unterscheiden sich grundsatzlich von den Sklerosen infolge symptomatischer unselbstandiger Entmarkungen in Begleitung anderer Krankheiten, besonders auf Grund von Kreislaufstorungen. 2. Die diffuse Sklerose im engeren Sinne ist ein Sammelbegriff fur das morphologische Durchschnittsbild verschiedener Krankheitsprozesse: a) entzundlicher (Leukencephalitis=Schildersche Krankheit) und b) degenerativer Natur (Leukencephalosen). Zu diesen letzteren gehort unter anderem die Leukodystrophie und diePelizaus-Merzbachersche Krankheit. 3. In einem neuen Fall von Leukodystraphie bei einem 2 1/2jahrigen Kinde zeigte sich eine allgemein verbreitete Markschadigung mit den bekannten atypischen Abbauprodukten, ahnlich wie diesvan Bogaert undScholz beschrieben haben. Bemerkenswert ist, das in unserem Falle auch die peripheren Nerven in gleicher Weise erkrankt waren. 4. Ein Entmarkungsprozes bei einem 5jahrigen Knaben wird als nicht ganz typischePelizaus-Merzbachersche Krankheit aufgefast und dem vorigen gegenubergestellt. Es ergibt sich, das diePelizaus-Merzbachersche Krankheit nicht als eine Untergruppe der Leukodystrophie anzusehen ist.

Introduction The nosologic position of the leukodystrophies has long been controversial. The heredodegenerative diseases of the white matter of the central nervous system have received but scant attention in American medical literature in spite of the appearance of many case reports, review papers, and classifications in European journals during the past 40 years. In 1957, after thorough study of available pathologic material and of the relevant literature, I proposed that two basic kinds of primary diseases of the myelin sheath existed.41The first, the myelinoclastic type, comprises the true demyelinating diseases and includes disseminated sclerosis, diffuse sclerosis of the 1912 Schilder type,47Devic's and Balo's diseases. In this type, the myelin sheath seems to be destroyed after having been normally constituted. The second type is exemplified by the leukodystrophies. In it there appears to be a disturbance of myelin anabolism. I suggested the term "dysmyelinating diseases" to identify

Biochemical investigation employing labeled sphingolipids has become a useful technic for determining the metabolic lesions in the sphingolipidoses. With these procedures, specific enzymatic defects have been demonstrated in Gaucher's disease, Niemann-Pick disease, Fabry's disease, and in metachromatic leukodystrophy. As suitable substrates become available, this method will be useful for elucidating the nature of the lesions in Tay-Sachs disease and generalized gangliosidosis. Enzymatic assays with labeled compounds performed on biopsy specimens from various tissues and white blood cell preparations have been helpful in establishing the diagnosis of the sphingolipidoses. Tissue cultures obtained from patients with Niemann-Pick disease show diminished sphingomyelin-cleaving enzyme as compared with control enzyme levels. Tests such as these should be of considerable diagnostic and prognostic usefulness, as well as being helpful adjuncts for the selection of proper therapeutic measures.

The ultrastructure of sural nerve biopsies was studied in two sisters with Cockayne's syndrome. Both had severe physical and mental retardation and evidence of peripheral neuropathy. Striking alterations in the myelin sheath with relative preservation of the axis cylinder were noted in both. There were also electron dense bodies in the Schwann cells. These findings support the suggestion that Cockayne's syndrome may be a form of leukodystrophy.

Es wird uber eine eigenartige, im 41. Lebensjahr beginnende, progressive Erkrankung eines mit 52 Jahren verstorbenen Mannes berichtet. Die klinischen und neuropathologischen Befunde lassen sich bei Berucksichtigung genealogischer Daten unter dem Begriff einer spat-adulten Leukodystrophie zusammenfassen.

The activity of galactocerebroside beta-galactosidase was extremely low in serum, leukocytes, and cultured fibroblasts of patients with Krabbe's disease. Antemortem diagnosis is possible without organ biopsies. The parents of patients showed enzyme activities generally lower than that of normal controls. This finding provides supportive evidence that the deficient activity of galactocerebroside beta-galactosidase is the genetically determined enzymatic defect underlying the disease. Demonstration of this deficiency requires the use of the specific substrate, galactocerebroside. Assays carried out with synthetic, unnatural substrates, such as 4-methylumbelliferyl beta-galactoside, do not distinguish patients or heterozygous carriers from normal individuals.

The activity of galactosyl ceramide and lactosyl ceramide β-galactosidase was measured in leukocyte and fibroblast homogenates. New incubation conditions for this assay provide a significantly more sensitive method than reported previously. Both reactions were stimulated by optimal concentrations of sodium taurocholate and oleic acid. Citrate-phosphate buffer, pH 4.2, was found to give maximum reaction. Galactosyi ceramide and lactosyl ceramide β-galactosidase activities in leukocytes, cultured skin fibroblasts and cultured amniotic cells from controls and patients with lysosomal disease were compared to carriers and patients with Krabbe's disease. Activity for lactosyl ceramide β-galactosidase was much greater than galactosyl ceramide β-galactosidase activity and may provide a new, more sensitive method for the diagnosis of Krabbe's disease as well as for the identification of suspected carriers. A prenatal diagnosis has been done using this new method.

THE classification of leukodystrophy in childhood is still complicated and unsettled. This report will attempt to contribute to the clinical and pathological classification and to describe an unusual combination of diffuse sclerosis of the white matter with total cerebellar atrophy. Report of a Case Family History. —The patient, a boy, was born on May 8, 1962, after an uneventful nine-month gestation. This was his mother's second pregnancy, her first pregnancy having resulted in an abortion at six weeks gestation. The mother was 23 years old and the father, 27 years of age. Both parents are of Anglo-Saxon ancestry and have no siblings. There is no history of a similar disorder in the family. There have been no additional pregnancies. Clinical Course. —The patient was delivered after ten hours of spontaneous labor. Membranes ruptured two to three hours before delivery. The mother was not awake for the actual delivery. The

Monogalactosyl diglyceride has previously been demonstrated to be intimately associated with brain white matter, especially myelin. Enzymes responsible for its biosynthesis and degradation have been reported to be present in rat and mouse brain. In the present study, the β-galactosidase responsible for the degradation of this brain specific compound was demonstrated to be extremely deficient in brain, liver and skin fibroblasts from patients who died of Krabbe's disease. This deficiency is the third enzymatic block demonstrated in this disorder. The β-galactosidase activity toward galactocerebroside and psychosine is also extremely deficient. This finding provides new information about the substrate recognition pattern of this enzyme and about the possible etiology of globoid cell leukodystrophy.

Quantitative investigations on the glial population in the corpus callosum were carried out on 7 Jimpy mice and on 4 normal controls of the same strain and age. A statistical analysis revealed a significant (p = 0.01) increase in the relative number of all spongioblastic cell types (large glial precursors) and a decrease in the relative number of astrocytes (15.4%) and oligodendrocytes (14.1%). However the relative number of small dark cells (small glioblasts) was similar to that of controls. The present findings suggest a delay in the differentiation of glial cells of Jimpy mice. Some spontaneous mutations in laboratory animals provide models of genetically determined disorders of the central nervous system. As reported by other authors ( Sidman , 1965; Sidman et al. , 1964), Jimpy mice offer new opportunities for studying the formation and function of myelin as well as the conditions in leucodystrophy ( Sidman and Hayes , 1965). More recent studies death with ultrastructural changes in myelin sheath and myelin formation ( Hirano et al. , 1969). Neurochemical investigations suggested a serious alteration of those glial cells which are essential for myelination of the central nervous system ( Nescovic et al. , 1969). Histochemical studies ( Torii et al. , 1971) revealed the absence of myelination and the presence of sudanophilic material in the cerebellum at 12 to 15 days after birth, which increased after three weeks of age. Glial cell changes were mentioned by Frakas et al. (1970) and Torii et al. (1971). In an attempt to obtain further information on morphological changes in the neuroglial cell population of the Jimpy mutant mouse, the properties of the different glial cell types were studied quantitatively in the corpus callosum and compared with normal controls.

The demyelinating diseases are characterized by a primary breakdown of myelin with more or less persistence of the axis cylinders and with secondary proliferation of astrocytes and microglial cells leading to sclerosis. The demyelination may be disseminated, as in multiple sclerosis, or diffuse. A disorder first described by Krabbe 1 in 1916 and known since then as Krabbe's disease is an example of the diffuse type of cerebral sclerosis. In the disseminated type of sclerosis numerous discrete, demyelinating foci of variable size are scattered throughout the brain and spinal cord. In the diffuse type, the lesions begin in one focus in the cerebral hemispheres and spread to involve adjacent white matter in a continuous fashion. Ultimately the demyelination extends from the paraventricular areas to the cortex, and usually it becomes bilateral and symmetrical. The classifications of the diffuse demyelinating diseases have undergone considerable revision since the development of histochemical

The genetic cause underlying globoid cell leukodystrophy (Krabbe’s disease) appears to be the deficiency of galactocerebroside β-galactosidase (galactosylceramide galactosyl hydrolase). Among postmortem organs, the deficiency was initially demonstrated in the brain, liver and spleen from three patients (11). This was later confirmed in the brain, liver and kidney of five additional patients (1, 13). Furthermore, the same deficiency has been demonstrated in peripheral leukocytes (5, 12), serum and cultured fibroblasts (12) from patients afflicted with this fatal neurological disorder. In addition to the diagnostic value of the galactocerebrosidase assay on these easily obtainable materials, our preliminary data indicated the possibility of heterozygous carrier detection utilizing these materials(12).

GLYCOLIPIDS are reduced in the brain in globoid leukodystrophy (GLD), and a distinctive change occurs in their proportions. 1,2 Typically, there is an increase in the ratio of cerebrosides to sulfatides in isolated globoid bodies, 3 in one partially purified "myelin fraction" 4 and in cerebral cortex. 5 The increase in cerebrosides is of particular interest because cerebrosides elicit a local globoid-like response when injected into experimental animals. 6,7 The decrease in sulfatides is also notable because in two GLD cases there was abnormally low activity of the enzyme system that synthesizes sulfatides. 8,9 The purpose of the present collaborative report is to consider several enzymic mechanisms which could cause the relative increase in cerebrosides and the decrease of sulfatides. Our present findings emphasize and further confirm the recent finding of a β-galactosidase deficiency in both human 10,11 and canine GLD. 12 Recent reviews of GLD are presented elsewhere.

Clinical history, histopathological, ultrastructural and biochemical observations are presented in a juvenile MLD with onset at 8 years and death at 20 years. The findings are compared with related ones in different age groups, and current views on sulfatide metabolism and enzymatic pathogenesis in MLD are briefly entertained. It is postulated that the relatively well established morphological and chemical stability of the nervous tissue at the time of appearance of the metabolic derangement was an important factor in the pathomechanism of the disease process in this particular variant.

Glycosphingolipids were isolated from the liver of four patients with globoid cell leukodystrophy and compared to those from normal liver. The ratio of glucosylceramide to galactosylceramide was 0.8, 1.2, 1.3 and 7.5 in the four cases studied, compared to a value of greater than 10 in liver from control patients of the same age and sex. In addition to this accumulation of galactosylceramide, all four livers showed an elevated level of sulfatide, and in one case trihexosylceramide and globoside were also markedly elevated.

— Dihexosylceramide from the brain of a case of globoid cell leukodystrophy was isolated and characterized. Studies utilizing partial acid hydrolysis and methylation indicated the carbohydrate sequence to be galactosylglucosylceramide. The carbohydrate moiety was liberated by ozonolysis and identified to be lactose by GLC. 4-Sphingenine and sphinganine were the only long chain bases detected. The chain length of the fatty acids present ranged from 14 to 25 carbons; C18, and C21 fatty acids composed one-half of the mixture. All analyses were performed by GLC and TLC utilizing micro-techniques.