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Biomedical subjects

T E Kelly

Publications and source records attributed to T E Kelly.

At least 91 records · Page 5Linked to original sources

The Rieger syndrome.

Fourteen patients with hypodontia and the ocular features of the Rieger syndrome were examined for the presence of systemic anomalies. A periumbilical defect that consisted of failure of the periumbilical skin to involute was seen in ten of the thirteen evaluated for the defect. Three others had scars over the umbilical area and had a history of surgery for herniation. In addition, four males in one family and one male from another family had hypospadias. None of several other anomalies reported to be components of the Rieger syndrome by other authors was detected in the fourteen patients. The mode of inheritance in the familial cases studied was compatible with autosomal dominance. The results of this study indicate that the Rieger syndrome is an autosomal dominant syndrome whose cardinal features are hypodontia, goniodysgenesis, and failure of the periumbilical skin to involute properly.

Abnormalities, Multiple↗

Isolated acid neuraminidase deficiency: a distinct lysosomal storage disease.

An 8-month-old female presented with coarse facies and hepatosplenomegaly at birth. Growth proceeded at an accelerated rate and mental development was normal. A pattern of dysostosis multiplex developed radiographically. Cytoplasmic inclusions consistent with lysosomal storage disease were demonstrated by electron microscopy in bone marrow, liver, and cartilage cells and in cultured skin fibroblasts. Assays of the fibroblasts revealed a specific deficiency of acid neuraminidase and 6-fold increase in intracellular bound sialic acid. An unidentified macromolecular compound rich in sialic acid was excreted in excessive amounts in the urine. The phenotype suggests defective degradation primarily of glycoproteins and possibly to a lesser extent of keratan sulfate and gangliosides.

Bone Marrow↗

Ganglioside GM2 N-acetyl-beta-D-galactosaminidase and asialo GM2 (GA2) N-acetyl-beta-D-galactosaminidase; studies in human skin fibroblasts.

Ganglioside GM2 and its asialo-derivative, GA2 were radiolabeled in their N-acetyl-D-galactosaminyl moieties by oxidation with galactose oxidase and reduction with tritiated sodium borohydride. Specific activities of 6 X 10(4) dpm/nmol (GM2) and 1.8 X 10(6) dpm/nmol (GA2) were achieved. About 98% of the label was in N-acetyl-D-galactosamine. Using these substrates, an assay was developed for GM2-N-acetyl-beta-D-galactosaminidase (E.C.3.2.1.30) and GA2-N-acetyl-beta-D-galactosaminidase (E.C.3.2.1.30) activities in human cultured skin fibroblasts. The products of the GM2 cleaving reaction were identified as N-acetylgalactosamine and ganglioside GM3. Both GM2 and GA2 cleaving activities were stimulated about 5-fold by purified sodium taurocholate, and this stimulation was inhibited by neutral detergents, lipids and albumin at low concentrations. Addition of various salts, reducing agents and a protein activator factor from human liver of Li et al. (1973) did not stimulate GM2-N-acetyl-beta-D-galactosaminidase activity beyond that found with sodium taurocholate. Under optimal conditions, control fibroblast supernates cleaved ganglioside GM2 at a rate of 3.7 nmol/mg protein/h compared to 1100 for GA2-N-acetyl-beta-D-galactosaminidase and 4700 for 4-methylumbelliferyl-N-acetyl-beta-D-glucosaminidase. Supernates from two patients with Tay-Sachs disease had markedly reduced activity levels for GM2-N-acetyl-beta-D-galactosaminidase but not for the other two substrates. Supernates from two patients with Sandhoff's disease had reduced activities for all three substrates. A supernate from one patient with juvenile GM2 gangliosidosis cleaved GM2 at a somewhat faster rate than those from Tay-Sachs or Sandhoff's patients. Two healthy adult women with markedly reduced hexosaminidase A activities using 4MU-N-acetyl-beta-D-glucosaminide as substrate had approximately half-normal activities using GM2 as substrate. A patient with the Tay-Sachs phenotype but with a partial deficiency of hexosaminidase A using the 4-MU substrate had a profound deficiency using GM2 as substrate. In such unusual hexosaminidase mutants, assays using GM2 as substrate are better indicators of phenotype than those using synthetic substrates.

Adult↗

Segregation within a family of two mutant alleles for hexosaminidase A.

A healthy adult female was found to have low levels of hexosaminidase A in serum, leukocytes and fibroblasts when these were assayed with artificial substrates. Fibroblast assay with GM2 ganglioside gave values consistent with a Tay-Sachs heterozygote. Studies of this non-Jewish family revealed evidence for segregation of two mutant alleles for hexosaminidase A.

Adult↗

Leucocyte values of alpha-L-iduronidase activity in mucopolysaccharidosis I.

Assay of alpha-L-iduronidase in peripheral leucocytes is a rapid and simple diagnostic aid in mucopolysaccharidosis I. The mean value for heterozygotes is one-half the value of normal controls, but overlap between the two groups occurs. Use of this assay may be helpful in genetic counselling of selected couples.

Glycoside Hydrolases↗

Myelopathy associated with Maroteaux-Lamy syndrome.

Myelopathy due to compression of the cervical spinal cord by thickened dura developed in a patient with Maroteaux-Lamy syndrome. During the last trimester of pregnancy there was severe neurological deterioration with spastic quadriparesis and impairment of sphincter function. Two months after delivery ther had been no improvement, so a cervical laminectomy and longitudinal splitting of the dura from C-5 to the foramen magnum was done. Good return of function resulted.

Adult↗

Tay-Sachs disease: high gene frequency in a non-Jewish population.

A non-Amish "Pennsylvania Dutch" semi-isolate was found to have a high frequency of Tay-Sachs gene. This high frequency could be ascribed to founder effect and may represent, in microcosm, how this mechanism could have produced the high gene frequency among Ashkenazi Jews.

Consanguinity↗

Mucolipidosis III (pseudo-Hurler polydystrophy): Clinical and laboratory studies in a series of 12 patients.

Mucolipidosis III (pseudo-Hurler polydystrophy) is an autosomal recessively inherited Hurler-like disorder without mucopolysacchariduria. Previous reports have noted a constellation of laboratory features similar to that described for mucolipidosis II (I-cell disease). Studies were carried out on a series of 15 patients. Twelve were found to have changes in serum and cultured fibroblasts which consisted of marked elevations of several acid hydrolases in serum with low levels of the same enzymes in cultured cells, a marked increase in dense cytoplasmic inclusions and abnormal radioactive sulfate kinetics. The clinical features of these 12 patients comprise a phenotypic entity. Despite clinical similarity, the 3 remaining patients were not felt to represent mucolipidosis III. The basic defect in mucolipidosis III remains unknown, but is suggested that the defect is similar to that of mucolipidosis II, from which it must be distinguished clinically.

Adolescent↗