Edwin H. Kolodny

Fabry disease Impaired autonomic function

Previous reports of extensive lipid accumulation within neurons of the autonomic nervous system in Fabry disease suggest an anatomicopathologic basis for the peculiar pain, diminished sweating, and gastrointestinal symptoms experienced in this disorder. To further assess autonomic function in Fabry disease, noninvasive clinical tests were performed on 10 patients. Diminished sweating was found in each; the loss was approximately uniform proximally and distally, suggesting sweat gland dysfunction rather than autonomic neuropathy. Impaired pupillary constriction with pilocarpine, and reduced saliva and tear formation were found in half the patients. Disordered intestinal mobility was demonstrated in the oldest patients. In all cases, the cutaneous flare response to scratch and intradermal histamine was diminished, and pruritus was not experienced. Signs of autonomic dysfunction are present in Fabry disease and correlate with the known lipid deposition in autonomic neurons.

Human leukocyte acid hydrolases: Characterization of eleven lysosomal enzymes and study of reaction conditions for their automated analysis

The optimal reaction conditions and kinetic properties of eleven leukocyte acid hydrolases determined with the use of fluorigenic derivatives of 4-methyl-umbelliferone are described. The enzymes studied were acid phosphatase, aryl sulfatase, alpha- and beta-glucosidase, alpha- and beta-galactosidase, alpha-mannosidase, N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-glucuronidase and alpha-fucosidase. More than 90% of the activity of each enzyme was released into a 27,000 X g supernatant by a double sonication procedure employing 0.9% sodium chloride and 0.1% Triton X-100. The Km values obtained were similar to those previously reported for chromogenic subtrates. A single Km value could not be derived for beta-galactosidase because its double reciprocal plot was not linear. All enzymes could be measured with less than 10 mug of protein within 15 min. Activators and inhibitors studied included the chloride salts of Na+, K+, Zn2+, Ca2+, Mg2+, Hg2+, and Fe2+ as well as p-chloromercuriphenysulfonate, glutathione, BAL, EDTA, EGTA, Triton X-100 and sodium taurocholate. The reaction conditions described in this report can be used for the diagnosis of various lysosomal storage diseases and should facilitate the development of automated procedures for the analysis of these eleven enzyme activities with small quantities of blood.

Fabry disease Significance of ultrastructural localization of lipid inclusions in dermal nerves

An ultrastructural examination of intradermal nerve fibers in Fabry disease revealed signs of lipid accumulation and small unmyelinated nerve fiber degeneration. Many axons were swollen, and their internal organelles were lost. In several damaged axons, dense inclusions, probably lipid, were observed. No lipid inclusions were found in Schwann cells, which may indicate that they utilize different metabolic processes or are impervious to ceramide trihexoside. It is hypothesized that Schwann cells and myelin sheaths act as a metabolic barrier protecting the larger myelinated fibers. Lacking this barrier, the smaller unmyelinated fibers are more susceptible to lipid infiltration. This view may explain the small fiber neuropathy in Fabry disease.

Characterization of 6-hexadecanoylamino-4-methylumbelliferyl-β-D-galactopyranoside as fluorogenic substrate of galactocerebrosidase for the diagnosis of Krabbe disease

6-Hexadecanoylamino-4-methylumbelliferyl-beta-D-galactopyranoside (HMGal) has been shown to be a specific fluorogenic substrate of galactocerebrosidase and to facilitate the simple enzymatic diagnosis of Krabbe disease in human patients and in twitcher mice. HMGal hydrolysis at pH 4.5 is optimally stimulated by sodium taurocholate (0.25%) and oleic acid (0.05%) with a Km of 0.150, 0.04 and 0.03 mM, respectively for control mouse kidney, human fibroblasts and leukocytes. In control samples, the specific activity (nmol/mg prot./h) for HMGal is higher than for the natural substrate, galactocerebroside, and is severely deficient in the twitcher mouse and in patients with Krabbe disease. Comparative investigation of galactocerebrosidase activity in fibroblasts, leukocytes and brain with radioactive and fluorogenic substrates reveals a good agreement between the results of the two methods. Galactocerebroside (Gal-Cer) is a competitive inhibitor of HMGal hydrolysis in mouse kidney homogenates while GM1-ganglioside has no inhibitory effect in the same assay system. The sensitivity and specificity of this fluorogenic substrate for galactocerebrosidase provides a simple and rapid method for the diagnosis of Krabbe disease, and for the purification of this enzyme from normal tissues.

Prenatal genetic diagnosis. 3.

More than 100,000 children are born in the U.S. each year with major congenital defects or genetic disorders, with or without mental retardation. Advances in prenatal diagnosis have now made it possible to detect an increasing number of these disorders in utero. Carrier detection is advised prior to pregnancy, rather than after the birth of a defective child, or during pregnancy itself. Patients have a right to know about their genetic risks and should have the freedom to exercise their options.

Fabry disease: detection of heterozygotes by examination of glycolipids in urinary sediment.

Fabry disease is an X-linked sphingolipid disorder that is manifest clinically as a disease of nerves, kidneys, and blood vessels. Precise identification of Fabry heterozygotes is essential for genetic counseling. Heterozygote detection by enzyme assay does not consistently distinguish them from unaffected females. We describe a method for Fabry heterozygote detection, based on quantitation of urinary sediment glycolipids by high-performance liquid chromatography. In specimens from 12 Fabry heterozygotes, the total glycolipid fraction was increased (10 to 100-fold) and trihexosyl ceramide (CTH) was 2-to 70-fold times normal. Digalactosyl ceramide (Digal-Cer), which is normally present in trace amounts in urine, was also increased. The ratio of CTH and Digal-Cer to hydroxy fatty acid glucosyl ceramide was increased and seemed to be characteristic of Fabry disease. This method provides rapid and accurate detection of Fabry heterozygotes.

A light and electron microscopic study of mannosidosis

The present work investigated the light and electron microscopic changes in hypertrophied gingiva in a patient with mannosidosis. The biopsy specimens studied covered a period of 20 months; biopsy specimens were taken before and after a therapeutic trial with oral and local zinc sulfate. The intensity of the disease was progressive, in spite of the zinc, and was characterized by marked hyperplasia of the epithelium and severe inflammation of the stroma. Many of the cells in the inflammatory infiltrate, as well as cells indigenous to the gingiva, showed a striking vacuolation of their cytoplasm. Histiocytes were most numerous and also were most heavily vacuolated, but fibroblasts, endothelial cells, plasma cells, and epithelial cells also manifested the vacuolar change. In the histiocytes, the vacuoles occupied most of the cytoplasm, ranged widely in size, and were contiguous, molded, and intercommunicating. The vacuoles were bound by a single membrane and were filled predominantly by a finely granular material of medium density but also by varying amounts of coarser, darker granules, fragmented membranes, myelin-like figures, lipid droplets, and small vesicles. The vacuoles were interpreted as being consistent with secondary lysosomes that contained excessively stored substrate, similar to what has been observed in the mucopolysaccharidoses, in which the vacuoles have also been demonstrated histochemically and cytochemically to contain acid phosphatase, a known lysosomal marker.

Sandhoff’s Disease: Studies on the Enzyme Defect in Homozygotes and Detection of Heterozygotes

Three varieties of GM2-gangliosidosis have been described. These can be distinguished by: their clinical presentation; the nature of lipid storage; and the nature of the enzyme deficiency. In Tay-Sachs disease, the most common form of GM2 -gangliosidosis, GM2 ganglioside accumulates within the nervous system and there is a deficiency of hexosaminidase A (1,2). In the United States, most of the children afflicted with this disease have been of Jewish parentage. A much rarer type of GM2-gangliosidosis known as Juvenile GM2-gangliosidosis (3,4,5) has in common with Tay-Sachs disease central nervous system accumulation of GM2 ganglioside and deficiency of hexosaminidase A. However, these biochemical abnormalities are less severe than in Tay-Sachs disease.

Macular Halos Associated with Niemann-Pick Type B Disease

Macular halos describe a striking clinical finding of bilaterally elevated, doughnut-shaped, white rings around th fovea. This paper presents the third well-documented report of the association of macular halos with Niemann-Pick type B disease, demonstrated by color photographs and subtle fluorescein angiographic findings. The systemic association with Niemann-Pick type B disease was confirmed by bone marrow biopsy and enzyme assay. Of 13 family members examined, only the proposita had macular halos; 10 were found to be carriers by sphingomyelinase assay. Recognition of this pathognomonic eye finding warrants more widespread awareness as a presenting sign of Niemann-Pick type B disease.

Retinal Pigment Epithelial Degeneration Associated with Leukocytic Arylsulfatase a Deficiency

A family exhibiting a leukocytic arylsulfatase A deficiency, probably inherited in an autosomal recessive manner, differed from patients with typical metachromatic leukodystrophy in that sulfatiduria was absent and there was readily detectable cerebroside sulfatase activity. To our knowledge, this family was unique in that there were no known members with metachromatic leukodystrophy and the only neurologic abnormality was progressive retinal pigment degeneration in the proband.