Tay-Sachs carrier detection.
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Clinical Enzyme Tests↗
Biomedical subjects
R S Wappner
Publications and source records attributed to R S Wappner.
Carrier detection in Sanfilippo syndrome type B: report of six families.
Serum samples from 175 individuals in six Sanfilippo syndrome type B (SFB) families and 360 White controls were assayed for serum alpha-N-acetyl-D-glucosaminidase (NAG) activity. Only minimal overlap was observed between the controls' NAG activity distribution and that of the 12 obligate heterozygotes. The distribution of NAG activity was log transformed to reduce skewness, and segregation of family members with a prior risk of being a SFB carrier was well within expected limits. However, in one consanguineous family the NAG activity of both parents of one SFB obligate heterozygote was within the normal range for NAG activity. Plausible explanations for this finding are discussed. Additionally, the serum NAG activity of one control and her mother were found to lie within one standard deviation of the obligate heterozygote mean. These individuals are most probably carriers for SFB.
Acetylglucosaminidase↗
Mucopolysaccharide storage disorders.
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Glycoside Hydrolases↗
Evidence of genetic variation for alpha-N-acetyl-D-glucosaminidase in black and white populations: a new polymorphism.
Serum and/or plasma samples from 360 Whites and 126 Blacks were assayed for activity of the lysosomal hydrolase alpha-N-acetyl-D-glucosaminidase (NAG). The samples from the Blacks had an increased mean (0.50 nm/ml/min) and standard deviation (0.30 nm/ml/min) compared to those from the Whites (0.29 nm/ml/min and 0.10 nm/ml/min, respectively). After loge transformation and admixture analysis, it was possible to demonstrate the presence of 3 distributions of NAG activity in Blacks and at least 2 in Whites. Segregation analysis of the NAG activity of 29 White half-sib twin families indicated that a genetic model for the inheritance of NAG activity provided a better fit (P less than 0.01) with the data than the "environmental" model. Thus, the study suggests the presence of a genetic polymorphism for NAG activity in Black and White populations. The presence of alleles for high and low NAG activity in the normal population could lead to incorrect interpretation of serum carrier tests for Sanfilippo syndrome, type B.
Acetylglucosaminidase↗
White cell ornithine transcarbamylase activity cannot detect the liver enzyme deficiency.
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Adult↗
The Chicago variant of clinical galactosemia.
A new variant of clinical galactosemia with two hitherto unidentified alleles on the transferase locus in one family is described. This new clinical variant of transferase has 25% of normal control activity in blood and in skin fibroblasts, and the patient accumulates galactose-1-phosphate in blood on an unrestricted galactose diet. Using starch gel electrophoresis on the hemolysate of the family members, a fast-moving transferase with mobility in between those of the normal control and of the Duarte variant is identified. This new allele is designated as GALTC1 (fast-moving Chicago variant). In addition, a second new allele was documented in this family by studying the instability of the transferase enzyme in hemolysates of family members at 50 degrees C for various time intervals. This new allele is designated as GALTC2 (heat-labile Chicago variant). On the basis of these studies, the transferase genotype of this patient is thought to be a double heterozygote compound, GALTC1/GALTG.
Alleles↗
7q deletion syndrome (7q32 leads to 7qter).
Four independently ascertained children who presented with unusual facies and delayed mental and physical development were found to have a similar deletion of part of the long arm of chromosome 7 (46,XX or XY, del(7)(q32); 46,XX or XY,del(7)(pter leads to q32:)). Comparison of the findings of these four cases with one other case report of a similar deletion revealed similar dysmorphologic features in all five cases.
Abnormalities, Multiple↗
Hurler syndrome: alpha-L-iduronidase activity in leukocytes as a method for heterozygote detection.
Alpha-L-Iduronidase activity and beta-galactosidase activity were determined in mixed leukocyte preparations in 10 families in which the Hurler syndrome had occurred. Affected patients, heterozygotes, and normal subjects were clearly distinguished by alpha-L-iduronidase activity alone. Patients had 0-3%, obligate heterozygotes 19-60%, and normal subjects 83-121% of the mean normal activity. There was no overlap between heterozygotes and normal subjects. Although the mean alpha-L-iduronidase to beta-galactosidase ratio was significantly lowered in heterozygotes when compared with that of normal subjects, appreciable overlap was noted between the two groups.
Adolescent↗
An artifact in the gas chromatographic analysis of urinary organic acids from phenylketonuric children: decarboxylation of the phenylpyruvic acid during extraction.
Phenylpyruvic acid is converted at least partially to phenylacetic acid during the normal extraction procedure used to obtain urinary organic acid profiles of phenylketonuric children by gas chromatography. This decarboxylation reaction can be reduced or completely eliminated by forming oxime derivatives prior to extraction.
Child↗