Toru Yutaka

A case of neuraminidase deficiency associated with a partial β-galactosidase defect

Neuraminidase deficiency towards fetuin, 2→3 sialyllactose and 2→6 sialyllactose was found in cultured skin fibroblasts from a 10-year-old Japanese girl who exhibits craniofacial dysmorphism, a short neck, vertebral and pelvic deformities and macular cherry-red spots. Neuraminidase deficiency in this case seems the primary enzyme defect because the enzyme activity of her parents was intermediate. In addition, β-galactosidase in leukocytes and cultured skin fibroblasts from the patient was found to be severely deficient, but could be detected in serum and urine. In the parents, β-galactosidase activity was normal. There were moderately increased levels of urinary sialic acid-rich oligosaccharides and glycopeptides in the patient. The clinical and biochemical observations suggest that this case is very close to mucolipidosis I.

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.

Insulin and glucagon secretion in hepatic glycogenoses.

ABSTRACT. Okada, S., Seino, V., Kodama, H., Yutaka, T., Inui, K., Ishida, M., Yabuuchi, H. and Seino, Y. (Department of Pediatrics, Osaka University Hospital, Fukushima‐ku, Osaka and The Third Division, Department of Medicine, University of Kobe, Kobe, Japan). Insulin and glucagon secretion in hepatic glycogenoses. Acta Paediatr Scand 68: 735, 1979.—Insulin and glucagon secretion was investigated in ten patients with hepatic glycogenosis, types I and III, in order to understand the relationship between hypoglycemia and pancreatic function. In all patients, both oral glucose tolerance and intravenous arginine infusion tests revealed hypoinsulinemia. Decreased urinary C‐peptide levels with standard food intake also supported hypofunction of pancreatic beta cells. On the contrary, the normal secretion pattern of glucagon in both types indicated in the arginine loading test, intact alpha cells in the pancreas. Persistent hypoinsulinism, which is apparently an adaptation to hypoglycemia, could be an important cause of nutritional dwarfism in both types of glycogenosis. The usefulness of the measurement of urinary C‐peptide, which evaluates the pancreatic function and provides management for normal body growth, is discussed.

Pathological study on a severe sialidosis (α-neuraminidase deficiency)

SummaryA 56-day-old infant with α-neuraminidase deficiency, whose clinical features included severe edema of extremities and ascites which resembled those in severe infantile sialidosis, was autopsied. Perforation, whose pathogenesis was unclear, was found on the descending portion of the duodenum. Light and electron microscope studies showed that neurons in the cerebral and cerebellar corticies, and the thoracic spinal cord contained membrane-bound vacuoles but no membranous cytoplasmic bodies. Zebra bodies were found only in the neurons of the spinal cord. The neurons in the paraganglion and in the Auerbachs myenteric plexus were also distended with numerous membrane-bound vacuoles. Hepatocytes, endothelial cells and Kupffer cells in the liver and glomerular and tubular epithelial cells in the kidney were swollen with a number of vacuoles although the patient showed none of the clinical features of renal involvement. These pathological changes were similar to those in nephrosialidosis reported by Le Sec et al. [Arch Fr Pediatr 35:819–829 (1978)].

A severe infantile sialidosis (β-galactosidase-α-neuraminidase deficiency) mimicking GM1-gangliosidosis type 1

We observed a 3-month-old Japanese female infant with severe psychomotor retaration, coarse facial appearance, hepatosplenomegaly, and dysostosis multiplex. Only β-galactosidase was found to be deficient when the routine lysosomal hydrolase assay was performed on the patients lymphocytes at 6 months of age. At first GM1-gangliosidosis type 1 seemed the most likely diagnosis. Later, however, additional studies (hydrolase assay in cultured skin fibroblasts, urinary oligosaccharide analysis, genetic complementation study, etc.) revealed that biochemical data of this case were in agreement with those of severe infantile sialidosis. The only important exception was that α-neuraminidase in the patients lymphocytes showed normal activity but abnormal pH dependence toward 4-methylumbellyferyl substrate. In addition, a severely damaged kidney suggested that his case may be classified as a unique type of severe infantile sialidosis (possible nephrosialidosis). These observations stress the importance of careful biochemical diagnosis of a case with GM1-gangliosidosis type 1 phenotype.

Ultrastructural study on nervous system of fetus with GM1-gangliosidosis type 1

SummaryThe nervous system of a 22-week-old fetus with GM1-gangliosidosis type 1 was studied by electron microscopy. The tissues thus examined were the cerebral cortex at the parietal region, the cerebellum, the thoracic spinal cord, the Auerbachs myenteric plexus in the large intestine and the radial nerve fibers. In the cerebral cortex, membrane-bound vacuoles, which occasionally contained stacks of fine fibrils, were observed in the large young neurons in the deeper part of the cortical plate. The neurons in the other part of the cerebral cortex carried no storage materials. In the cerebellum, the membrane-bound vacuoles with stacks of fine fibrils were seen only in the Purkinje cells. The neurons in the spinal cord also contained several zebra-like bodies and the above membrane-bound vacuoles. As for the peripheral nervous system (PNS), neurons in the Auerbachs myenteric plexus carried membranous cytoplasmic bodies and zebra-like bodies. Some of the axons in the radial nerve fibers also contained a lot of pleomorphic electron-dense bodies and a few membranous cytoplasmic ones. These results show that the accumulation of storage materials is started in the large neurons which are produced in the early stage of neurogenesis in the central nervous system (CNS). Additionally, the observed membrane-bound vacuoles are considered to be structures which occur before the membranous cytoplasmic bodies and/or the zebra-like bodies. It is also elucidated that the PNS is affected earlier than the cerebral and cerebellar cortices and thoracic spinal cord.

A case of mucolipidosis II: Biochemical, nutritional, and immunological studies

A case of mucolipidosis II was studied biochemically, nutritionally and immunologically. A possible functional deficiency of T cells was observed, but discrepancy between B cells and immunoglobulin content was not reasonably explained at this moment. There was no basic nutritional problem in this case and it is more likely that his growth retardation was due to frequent episodes of severe respiratory infection because he received adequate calorie intake with low normal basal metabolic rate. Results of enzymatic assays were also presented.

Hexosaminidase a activity in skin fibroblasts from various types of GM2 gangliosidosis using a fluorogenic sulphated substrate

13-Hexosaminidase (EC 3.2.1.52) is mainly composed of two isozymic forms consisting of hexosaminidase A (Hex A) and hexosaminidase B (Hex B). Genetic defects in these isozymes result in various clinical and biochemical types of GM2 gangliosidosis. They include Tay-Sachs disease (TSD, severe deficiency of Hex A), Sandhoff disease (severe deficiency of Hex A and B), juvenile and adult GMz gangliosidosis (deficiency of Hex A) and A~B variant (deficiency o f Hex A not detectable by a usual fluorogenic substrate assay). Diagnosis of patients with those disorders and identification of carriers have relied on the use of fluorogenic substrates, such as 4-methylumbelliferyl-2acetamido-2-deoxy-13-D-gtucopyranoside (MU-glcNAc). As both Hex A and Hex B react with MUglcNAc, methods for separating these two isozymes were developed. These include selective heat or pH denaturation and electrophoretic or ion-exchange separation. Kresse et al. (1981) demonstrated that a sulphated derivative of p-nitrophenyl-2-acetamido-2-deoxy-13-Dglucopyranoside (pNP-glcNAc) was a specific substrate for Hex A. Recently it was utilized as a diagnostic test for Tay-Sachs disease using serum (Fuchs et al., 1983). We synthesized a corresponding fluorogenic substrate, 4-methylumbelliferyl-6-sulpho-2-acetamido-2-deoxy-f3D-glucopyranoside (MU-glcNAcS) and confirmed the usefulness of this substrate for diagnosis of GM2 gangliosidosis including AMB variant in leukocytes (Inui and Wenger, 1984). In this study we used this substrate and radiolabelled hyaluronic acid-derived trisaccharide (also specific for Hex A) and found more residual activity for MU-glcNAcS in skin fibroblasts from chronic (adult) GMz gangliosidosis.

Chromatographic study of serum hexosaminidase in normal and GM 2-gangliosidosis.

Abstract β- N -Acetylhexosaminidase in normal human serum was separated into four components by DEAE-cellulose chromatography. The first three peaks were all heat stable. Neither conversion from heat-labile to heat-stable components, nor mutual conversion among heat-stable components occurred by heat treatment of serum. Serum hexosaminidase of Tay—Sachs disease patients had a high level of heat-stable components, especially of I 1 and I 2 , and this was similar to that of brain tissue. The activity of each component of a heterozygote of Tay—Sachs disease and Sandhoffs disease was intermediate between the normal and patient levels.