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Biomedical subjects

E F Neufeld

Publications and source records attributed to E F Neufeld.

At least 91 records · Page 5Linked to original sources
PubMed1977

X-linked Hunter syndrome: the heterozygous phenotype in cell culture.

Fibroblast cultures derived from the skin of three Hunter heterozygotes have been examined for iduronate sulfatase deficiency primarily by measurement of [35S]-mucopolysaccharide accumulation in the presence and absence of Hunter corrective factor. For each heterozygote, two populations of clones were observed: normal and enzyme deficient, as predicted by the Lyon hypothesis. However, the phenotype of the uncloned cultures was usually normal, presumably because of cross-correction, even after storage in liquid N2. Mixing experiments indicate that the presence of a majority of cells with the Hunter phenotype may be obscured as the result of correction by the minority population of normal cells in the mixture. Variability in the ability to cross-correct was also demonstrated. The unpredictable behavior of uncloned cultures make them unsuitable for diagnosing the Hunter carrier state.

Cells, Cultured↗
PubMed1977

The Hunter syndrome in females: is there an autosomal recessive form of iduronate sulfatase deficiency?

Profound iduronate sulfatase deficiency, characteristic of the Hunter syndrome, has been found in cultured fibroblasts, serum, lymphocytes, and tissues of two clinically affected girls. The patients are karyotypically normal and have normal fathers; cloning of the mothers' fibroblasts did not reveal the mosaicism expected of carriers of an X-linked disease. Homozygosity for a previously unsuspected autosomal recessive gene for iduronate sulfatase is considered the most likely explanation, although heterozygosity for the X-linked gene and subsequent selection cannot be completely excluded.

Child↗
PubMed1976

The iduronidase-deficient mucopolysaccharidoses: clinical and roentgenorgraphic features.

Hurler and Scheie syndromes, two of the six clinically distinct mucopolysaccharidoses, are deficient in the same lysosomal enzyme, alpha-L-iduronidase. A third group of iduronidase-deficient patients can now be identified during the pediatric years using clinical and radiographic criteria. Based on inferential evidence for allelism between the Hurler and Scheie genes, the occurrence of genetic compounds which simultaneously carry both mutant alleles may be predicted to occur. This can be considered analogous to the structural gene mutations leading to hemoglobin SC disease. Four patients with phenotypes intermediate between Hurler and Scheie syndromes are flet to represent genetic compounds of this type. Both clinical and roentgenographic features are helpful in distinguishing these patients from those with Hurler syndrome or Scheie syndrome. Fibroblast correction characteristics identical to those of Hurler syndrome and Scheie syndrome and absence of consanguinity are additional features which favor classification as genetic compounds. The possibility of a third mutant allele at the Hurler-Scheie locus or of extreme phenotype variation are not considered likely alternative explantations. Depending on the frequency of the Scheie syndrome and the Hurler syndrome, genetic compounds may occur with an intermediate frequency or may be more common than either homozygous condition.

Adolescent↗
PubMed1973

The defect in the Hunter syndrome: deficiency of sulfoiduronate sulfatase.

Skin fibroblasts cultured from patients affected with the Hunter syndrome are deficient in the activity of a protein, named the "Hunter corrective factor," that is required for degradation of dermatan and heparan sulfates. We now show that this factor, purified from human urine, removes about 2% of the sulfate residues from [(35)S]mucopolysaccharide accumulated within Hunter fibroblasts; these groups are derived from "oversulfated" regions of the polymer. Acetone-powder extracts of fibroblasts derived from patients with the Hunter syndrome are deficient in this sulfatase, in contrast to similar extracts from fibroblasts of individuals of other genotype. Hunter corrective factor coupled to alpha-L-iduronidase (or alternatively, mixed extracts from Hurler and Hunter fibroblasts) release iduronic acid from 4-O-alpha-L-sulfoiduronosyl-D-sulfoanhydromannose. We conclude that the Hunter corrective factor is a sulfatase for sulfated iduronic acid residues.

Carbohydrate Metabolism, Inborn Errors↗