SEARCH · PubMed Health

Results for “Heterozygote”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed1979

Intracellular phenylalanine and tyrosine concentrations in 19 heterozygotes for phenylketonuria (PKU) and 26 normals. Do the higher values in heterozygotes explain their lowered intellectual level?

Intracellular phenylalanine and tyrosine was determined in lymphocytes of 10 heterozygotes (parents) for PKU and in 26 randomly collected apparently normal persons. In cells from the heterozygotes the concentrations of both phenylalanine and tyrosine were higher than in those from the normals, the difference being statistically highly significant. It is argued that this could be responsible for the slight, though statistically significant, intellectual inferiority of heterozygotes for PKU.

Female↗

PubMed1979

Occurrence of G gamma Hb F in Greek HPFH: analysis of heterozygotes and compound heterozygotes with beta thalassaemia.

Haemoglobin F has been isolated from the red cells of individuals with the Greek form of hereditary persistence of fetal haemoglobin (HPFH), and the glycine/alanine composition of the gamma CB3 peptides determined. In contrast to previous reports we have shown that the Hb F of the Greek HPFH heterozygotes contains significant amounts of G gamma chains and circumstantial evidence indicates that these are the products of the same chromosome that carries the Greek HPFH determinant. Hence this chromosome must be directing the synthesis of G gamma, A gamma and (probably) beta and delta chains, thus implying that the Greek form of HPFH does not result from a deletion involving the globin chain structural genes. Analysis of the levels and structure of Hb F from the Greek HPFH heterozygotes and from separated cell populations from the Greek HPFH/beta thalassaemia compound heterozygotes indicate that the Greek HPFH determinant, while allowing an overall increase in gamma chain synthesis, is not the sole factor determining the absolute amount of Hb F production on a cellular basis.

Adult↗

PubMed1978

Heterozygote expression in propionyl coenzyme A carboxylase deficiency. Differences between major complementation groups.

We measured propionyl coenzyme A carboxylase (PCC) activity in extracts of skin fibroblasts and peripheral blood leukocytes from controls and obligate heterozygotes for PCC deficiency. 6 heterozygotes were from the pcc A complementation group; 12 were from the other major complementation group, designated pcc C. Mean PCC activity in fibroblast extracts from pcc A heterozygotes was 52% of that in controls, whereas mean PCC activity in pcc C heterozygotes was indistinguishable from that of controls. Similar results were obtained with extracts of peripheral blood leukocytes. In none of eight families (three pcc A and five pcc C) in which PCC activity was studied in both parents of an affected child were significant intrafamilial differences observed. The activities of two other mitochondrial enzymes (beta-methyl-crotonyl CoA carboxylase and glutamate dehydrogenase) were comparable in controls and both groups of heterozygotes. Whereas the data from pcc A heterozygotes are consistent with expected gene dosage effects, those from pcc C heterozygotes are not. Inasmuch as mammalian PCC is a large molecular weight tetramer, each protomer of which is probably composed of two nonidentical subunits, the latter results are most consistent with unbalanced rates of synthesis and(or) degradation of the two subunits in normal cells with compensatory balancing in pcc C heterozygotes.

Alleles↗

PubMed1977

Heterozygote detection in angiokeratoma corporis diffusum (Anderson-Fabry disease). Studies on plasma, leucocytes, and hair follicles.

Heterozygote detection for angiokeratoma corporis diffusum (Anderson-Fabry disease, ACD), an X-linked disorder of glycosphingolipid metabolism was examined using alpha-galactosidase activity, an alpha-galactosidase/beta-galactosidase activity ratios (alpha/beta ratio) in leucocytes, plasma, and hair follicles; For leucocytes, 22 obligate heterozygotes, 25 suspected heterozygotes, and 47 control subjects were studied, while for plasma, the groups were 17 obligate heterozygotes and 35 controls. The alpha/beta ratio in plasma and leucocytes was clearly a better discriminator between obligate heterozygotes and controls than alpha-galactosidase activity alone, but still failed to detect 3 obligates with leucocytes and 2 with plasma. Discrimination was not improved by joint use of plasma and leucocyte alpha/beta ratios, but was improved by measurement of hair-follicle alpha/beta ratios. The interdecile range of log (alpha-galactosidase/beta-galactosidase activity) in 20 hair follicles from each of 4 obligate and 7 suspected heterozygotes was clearly different from 11 control subjects. Accordingly, for rapid screening for carriers of ACD, we recommend use of leucocyte or plasma alpha/beta ratios which should detect greater than 85% of heterozygotes. When results are equivocal, and ancillary information suggests heterozygous status, the more time-consuming measurement of hair-follicle alpha/beta ratios is a useful additional test.

Fabry Disease↗

PubMed1976

Isoenzymes of serum N-acetyl-beta-D-glucosaminidase in the I cell disease heterozygote.

Serum N-acetyl-beta-D-hexosaminidase is compared quantitatively and qualitatively in 14 obligate heterozygotes for the mutant gene causing I cell disease (ICD) or mucolipidosis II and in 31 normal controls. The average specific activity in either group is significantly different but reliable heterozygote detection cannot be achieved because of some overlapping of the ranges of individual results. Fractionation of the enzyme either by DEAE cellulose column chromatography, or by heat inactivation, yields a typical average result for each genotype. Also, mere expression of the various components as percentages of the total activity is not useful for certain identification of the ICD heterozygote. There is considerable overlapping of the percents hexosaminidase I1 and A in both groups of sera. If enzymatic hydrolysis by any component is expressed as a partial activity, a much better though not absolute distinction between the ICD heterozygote and the normal control becomes possible. Only the latter way of expression of hexosaminidase results makes distinction between the ICD heterozygote and the Tay-Sachs heterozygote very probable.

Acetylglucosaminidase↗

PubMed1979

Linkage analysis using heterozygote detection in phenylketonuria.

This linkage investigation was undertaken utilizing an improved method for phenylketonuria (PKU) heterozygote detection. This method is based on studies of semi-fasting, noon-time, blood specimens obtained from 85 obligate heterozgotes and 45 controls who were neither pregnant nor on birth control medication. The best separation between heterozygotes and normals was achieved with a discriminant function involving the logarithms of the serum concentrations of phenylalanine, tyrosine and tryptophan. The theoretical overlap area between the distributions of heterozygotes and controls, based on the above function, was between the distributions of heterozygotes and controls, based on the above function, was 3.75%. In 19 obligate heterozygotes and 13 controls who were either pregnant or on birth control medication, the best separation was achieved with a discriminant function involving the logarithms of the serum concentrations of phenylalanine and tyrosine. The theoretical overlap area was 8.23%. These equations identified heterozygotes with sufficient accuracy to permit efficient genetic linkage analysis. We were unable to demonstrate genetic linkage between the PKU locus and 15 common blood, serum, and urinary markers. All but loose linkage (theta greater than 0.3) was excluded for Rh, ABO, Gc, Kidd, and AP. Moderate linkage exclusion (theta less than 0.2) was shown for PGM, Duffy, Hp, MNS, HL--A, and Kell. Close linkage (theta less than 0.1) was excluded for Amy2, 6PGD, P, and ADA. We were unable to find linkage heterogeneity between the Amish and non-Amish populations.

Chromosome Mapping↗

PubMed1976

[Color discrimination in heterozygotes].

By the help of Rabkin polychromatics tables and of the AN-59 anomaloscope it is studied the chromatic eye sight at 33 heterozygots. The used tests have permitted the identification of the different types of heterozygots: heterozygots which transmit and manifest only one chromatic anomaly, double heterozygots which manifest clinical one or both anomalies and unmanifested clinical heterozygots. The study of the chromatic eyesight at men from the same family has confirmed the clinical diagnosis of the heterozygots type in every case.

Color Perception↗

PubMed1978

The urinary excretion of radiocopper in presymptomatic and symptomatic Wilson's disease, heterozygotes and controls: its significance in diagnosis and management.

Radiocopper (64Cu, 67CU), given intravenously, has been used to study the pattern of excretion of copper in patients with presymptomatic, symptomatic and treated Wilson's disease, together with heterozygotes for the Wilson's disease gene and a control group of patients with a variety of neurological lesions mimicking Wilson's disease. Urine was collected for three periods after injection, 0 to 8 hours, 8 to 24 hours, at which time a test dose of penicillamine was given, and from 24 to 30 hours. Stable (endogenous) copper was also estimated on these samples and specific activity was determined. This was multiplied by a correction factor to allow for variations in dose and body weight. The findings for stable copper in urine were largely predictable. Controls and heterozygotes had the least copper excretion, the amounts rising in the presymptomatic to a peak in the symptomatic patients. Institution of therapy was associated with a fall in copper excretion pro rata with time. The most important radiochemical findings were as follows. Heterozygotes excreted less of the injected copper than controls both under basal conditions and after penicillamine. Presymptomatic patients excreted less radiocopper than heterozygotes after penicillamine although the excretion during the basal 24 hour period was very much greater. Patients with symptomatic Wilson's disease had by far the highest excretion of radiocopper in all three time periods which fell after treatment, pro rata with time, as had been found for stable copper. These results were subjected to computer analysis. There was no overlap between the various groups with the exception of a single control subject who had combined pyramidal and extrapyramidal system degeneration of obscure aetiology. This patient was classified by the computer study as 'heterozygote'. These findings lend further support to the hypothesis that the loss of a single gene for copper balance can be detected with a high degree of accuracy and also that presymptomatic patients can be selected from a sibship for prophylactic treatment without the risk of subjecting healthy heterozygotes to unnecessary and potentially hazardous long-term therapy.

Adolescent↗

PubMed1977

Hypoxanthine-guanine phosphoribosyltransferase activity in individual erythrocytes: autoradiographic studies in heterozygotes.

Heterozygotes for the Lesch-Nyhan syndrome have normal hypoxanthine-guanine phosphoribosyltransferase (HGPRT) activity in their erythrocyte lysates. However, HGPRT activity in lysates from heterozygotes for the partial HGPRT deficiency states is often between that seen in the affected hemizygote and the normal. An autoradiographic technique was developed which demonstrated the HGPRT activity in individual erythrocytes in vitro. This technique revealed that heterozygotes for the Lesch-Nyhan syndrome had erythrocytes that contained normal HGPRT activity but heterozygotes for the partial deficiency had two populations of erythrocytes, one with normal HGPRT activity and the other with the reduced HGPRT activity characteristic of the hemizygote. With these latter heterozygotes, the proportion of HGPRT-deficient erythrocytes agreed with that calculated on the basis of enzyme activity in erythrocyte lysates.

Autoradiography↗

PubMed1979

Heterozygote manifestation in recessive generalized myotonia.

The frequency of heterozygotes of recessive generalized myotonia may be estimated at about 1/108 in the German Federal Republic. Some heterozygotes can be identified by an EMG. However, apart from this, apparently 2%--5% of heterozygotes may show minor subclinical manifestations. Sporadic cases of myotonia with late onset and a history of preceding, extremely prolonged physical stress, undernourishment, and/or prolonged cold exposure may be due to heterozygote manifestations of this otherwise recessive gene. Late onset and sporadic appearance also are features in patients with myotonia associated with hypothyroidism. One male patient displayed myotonia after a protracted diabetic coma. In cases reported in the literature where myotonia developed in association with either propranolol (beta-adrenergic blocking agent) or fenoterolhydrobromide (stimulator of beta receptors) heterozygote manifestation of recessive generalized myotonia is suggested.

Adolescent↗

PubMed1978

Human erythrocyte pyruvate kinase deficiency: the use of a kinetic study of mutant enzymes for the detection of heterozygotes.

Erythrocyte pyruvate kinase (PK) deficiency was detected in a boy of dutch origin. Immunologic, electrophoretic, and kinetic studies of the enzymes of propositus and the members of his family demonstrated that the boy was heterozygote for two different mutant PK alleles. The mutant enzyme, for which his mother was heterozygote, was characterized by a lower immunologic specific activity, a decreased affinity for the substrate phospho-enol-pyruvate, and a loss of homotropic interactions toward this substrate, an increased affinity toward the allosteric inhibitor MgATP2-, a decreased affinity for the activator fructose-1,6-diphosphate, and a lowered pH optimum. Electrophoresis, Km app. for MgADP, and the reactivity toward the purine nucleotide substrate analogues were normal. The mutant enzyme for which his father was heterozygote was characterized by a decreased affinity for the substrate phospho-enol-pyruvate and a loss of homotropic interactions toward this substrate. All other parameters mentioned above were normal. The use of a kinetic study of mutant enzymes for the detection of heterozygotes is discussed.

Adolescent↗

PubMed1976

Biokinetics of galactose in the homozygotes and heterozygotes of both forms of galactosemia.

41 heterozygoes and 4 homozygotes with a deficiency of galactose 1-phosphate uridyl transferase and also 3 heterozygotes and 1 homozygous patient with galactokinase deficiency were subjected to intravenous galactose loading tests with a dose of 350 mg/kg body weight in order to answer the question whether it is possible to detect the heterozygotes of both types of galactosemia by this method. For comparison, 38 healthy children and adolescents, 24 children with epidemic hepatitis and 4 children with cirrhosis of the liver, which was verified by histology, were included in the study. The elimination half-life (and also the other pharmacokinetic parameters as inaugurated by Dost) was the same for all the heterozygotes for both types of galactosemia almost without exception, and for the healthy cs, children in the acute stages of hepatitis and patients with cirrhosis of the liver was prolonged 2 to 5 times the normal. In patients with hepatitis, however, the elimination half-life was normal before the transaminases. Accordingly, the galactose clearance was decreased to half and one-fourth of the normal. Hence, heterozygotes with galactosemia cannot be detected with galactose loading tests.

Adolescent↗

PubMed1977

Excretion of galactitol in the urine of heterozygotes of both forms of galactosemia.

In 36 heterozygotes with Gal-1-PUT deficiency and 3 heterozygotes with galactokinase deficiency galactitol (and galactose) was determined in the urine 2 and 4 h after an intravenous injection of 350 mg galactose/kg body weight (maximum dosis in adults 16 g). For the sake of comparison 10 healthy children and 5 adults, also 4 homozygotes with Gal-1-PUT deficiency and one sick child with galactokinase deficiency were included in this study. The heterozygotes with Gal-1-PUT deficiency demonstrated the same galactitol excretion as the healthy probands, while heterozygotes with galactokinase deficiency excreted a four-fold higher quantity of galactitol than the healthy and heterozygous probands of Gal-1-PUT deficiency. The child with the galactokinase deficiency excreted galactitol for a period of more than 24 h. These results are discussed.

Galactose↗

PubMed1978

Detection of Fabry's disease heterozygotes by hair root analysis.

The alpha-galactosidase/beta-hexosaminidase ratio was measured for individual hair roots as a method for heterozygote detection in Fabry's disease. Hair root analysis in control individuals revealed no striking sex difference in alpha-galactosidase/beta-hexosaminidase ratio when five males and five females were compared. The values for the ratio X 100, calculating both enzyme activities in nmol of product per min per microliter of hair extract, ranged from 0.8 to 9 for controls and from less than 0.1 to 0.4 for two hemizygous males. Hair root analysis in four heterozygotes with clinical evidence of disease gave values for each individual in the control range, in the range for hemizygotes and in an intermediate range. The experience using hair root analysis for heterozygote detection in the X-linked Lesch-Nyhan syndrome suggests that this approch will be a sensitive heterozygote detection method which takes advantage of the occurrence of hairs with a deficient phenotype on the basis of Lyonization. We observed an affected male who was born to a female without clinical or biochemical evidence (examination included extensive hair root analysis) of Fabry's disease, thus documenting a likely instance of new mutation.

Adult↗

PubMed1979

Pulmonary function in heterozygotes for alpha,-antitrypsin deficiency: a case-control study.

In this paper we present the initial cross-sectional data from a prospective study of lung aging in heterozygotes for alpha 1-antitrypsin deficiency. Using a case-control design, our cases included 37 heterozygotes for alpha 1-antitrypsin deficiency, protease inhibitor phenotypes MZ and MS, selected because they were parents of children with homozygous alpha 1-antitrypsin deficiency identified in a statewide newborn screening program between 1971 and 1974. All of the heterozygotes were less than 40 yr of age. Our control subjects were selected from a random sample of a working population participating in a longitudinal study of lung aging, using a 2:1 match of control subjects to cases, matching age, sex, ethnic origin, and smoking. Using a respiratory symptom questionnaire, spirometry, and the single-breath N2 test, we found no significant difference between heterozygotes and control subjects in terms of respiratory symptoms or pulmonary function data. We conclude that to 40 yr of age, the heterozygous phenotype (Pi MZ and MS) is not a risk factor for impairment of pulmonary function.

Adult↗

PubMed1976

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↗

PubMed1979

Arginase and free amino acids in hyperargininemia: leukocyte arginine as a diagnostic parameter for heterozygotes.

Arginase activity and free amino acids were measured in plasma, erythrocytes and leukocytes of patients with hyperargininemia and in controls. There is no arginase activity in the leukocytes and erythrocytes of homozygous patients; in heterozygotes it is normal to low. The activity is 50 to 100 times higher in leukocytes than in erythrocytes. In controls as well as in patients and heterozygotes, the amino acid concentrations are higher in leukocytes than in plasma and erythrocytes. In addition to the increased arginine in the three blood compartments (the result of an arginase deficiency), there is also an obvious decrease of aspartic acid in the erythrocytes of the patients. The arginine concentration in leukocytes of heterozygotes is as high as in homozygotes and can therefore be used as a diagnostic parameter for heterozygotes.

Amino Acid Metabolism, Inborn Errors↗

PubMed1979

Evidence for a hybrid hexosaminidase isoenzyme in heterozygotes for Sandhoff disease.

Patients with Sandhoff disease have less than 5% of normal levels of serum or tissue hexosaminidase activity. They are thought to have a defect in the structural gene for the beta chain of hexosaminidase (HEX). Heterozygotes for Sandhoff disease have approximately 50% of the total serum HEX activity of normals and more than 75% of the HEX is heat-labile. In normals, only 55%--65% of serum HEX is heat-labile. Serum HEX separates into three forms on DEAE cellulose chromatography: HEX A, a tetramer of 2 alpha and 2 beta chains, and HEX I and B composed solely of beta chains. The DEAE chromatograms from normals and Sandhoff heterozygotes did not differ in the relative distribution of HEX activity between peaks. In normals, the HEX A peak was heat-labile (60 degrees C for 9 min), but HEX I and B were heat-stable. In Sandhoff heterozygotes, however, HEX I and B were only 50%--53% heat-stable. This suggests the heterozygotes synthesized a hybrid enzyme containing both mutant and wild-type beta chains for HEX. The mutant beta chain renders the isoenzyme less stable to heating.

Female↗