Abnormal Allele Research Articles

Retroviral activation of interleukin 2 gene in a gibbon ape T cell lymphoma line.

The gibbon ape leukemia virus (GaLVSF)-infected T cell line, MLA 144, was established from the lymphoma of a gibbon ape. The cell line constitutively expresses IL-2 and its receptor, implying that an autocrine mechanism could be responsible for or contribute toward its growth. To explore the mechanism of constitutive IL-2 expression in MLA 144, we have isolated and characterized cosmid clones representing a normal and a doubly inserted IL-2 allele in this cell line. The map of the normal MLA 144 IL-2 allele closely resembles that of the normal human IL-2 gene. The abnormal allele contains a 3' insertion that is a GaLVSF provirus with two long terminal repeats (LTR) and an internal 3.25 kb deletion. At the 5' end of the abnormal allele is a second insertion that DNA sequencing showed to be an isolated GaLVSF LTR with a transcriptional orientation opposing that of the IL-2 gene. We demonstrate by Northern blotting analysis that the vast majority of transcripts are from the abnormal allele, implying that one or both retroviral insertions are responsible for constitutive expression of the allele.

The inheritance of Gilles de la Tourette's syndrome and associated behaviors. Evidence for autosomal dominant transmission.

We examined specific genetic hypotheses about the mode of transmission of Gilles de la Tourette's syndrome, by performing segregation analyses in 30 nuclear families identified through 27 index cases. Because data from earlier family studies had suggested that chronic tics and obsessive-compulsive disorder may be alternative phenotypic expressions of the diathesis of Tourette's syndrome, we used three diagnostic schemes to specify affected family members (Tourette's syndrome only; Tourette's syndrome or chronic tics; and Tourette's syndrome, chronic tics, or obsessive-compulsive disorder). The estimates of penetrance for the genotypes AA, Aa, and aa (A denotes the abnormal allele) in the analyses of subjects with Tourette's syndrome, chronic tics, or obsessive-compulsive disorder were 1.000, 1.000, and 0.002, respectively, for male subjects and 0.709, 0.709, and 0.000 for female subjects. These results predict that approximately 10 percent of all patients are phenocopies. We conclude that our analyses provide strong support for the hypothesis that obsessive-compulsive disorder is etiologically related to Tourette's syndrome and chronic tics in these families, and that Tourette's syndrome is inherited as a highly penetrant, sex-influenced, autosomal dominant trait.

Rearrangement at the 5' end of amplified c-myc in human COLO 320 cells is associated with abnormal transcription.

The proto-oncogene c-myc is amplified in sublines of human COLO 320 cells carrying either homogeneously staining chromosomal regions or double minutes. COLO 320 cells carrying homogeneously staining chromosomal regions have 15 to 20 copies of an apparently normal c-myc allele and 1 to 2 copies of an abnormal c-myc allele lacking exon 1 and express high levels of a normal c-myc mRNA 2.5 kilobases in size. COLO 320 cells carrying double minutes have about 25 copies each of the normal allele and the abnormal allele but express preferentially an abnormal c-myc mRNA 2.2 kilobases in size. Nucleotide sequence analyses revealed that the break point of rearrangement resulting in the loss of exon 1 in the abnormal allele lies within a region frequently rearranged in human and murine B-cell tumors.

Rearrangement at the 5' end of amplified c-myc in human COLO 320 cells is associated with abnormal transcription.

The proto-oncogene c-myc is amplified in sublines of human COLO 320 cells carrying either homogeneously staining chromosomal regions or double minutes. COLO 320 cells carrying homogeneously staining chromosomal regions have 15 to 20 copies of an apparently normal c-myc allele and 1 to 2 copies of an abnormal c-myc allele lacking exon 1 and express high levels of a normal c-myc mRNA 2.5 kilobases in size. COLO 320 cells carrying double minutes have about 25 copies each of the normal allele and the abnormal allele but express preferentially an abnormal c-myc mRNA 2.2 kilobases in size. Nucleotide sequence analyses revealed that the break point of rearrangement resulting in the loss of exon 1 in the abnormal allele lies within a region frequently rearranged in human and murine B-cell tumors.

A heterozygous collagen defect in a variant of the Ehlers-Danlos syndrome type VII. Evidence for a deleted amino-telopeptide domain in the pro-alpha 2(I) chain.

A structural defect in the alpha 2(I) chain of type I collagen was characterized in a new case of the Ehlers-Danlos syndrome type VII. The patient's skin, fascia, and bone collagens all showed an abnormal additional chain, pN-alpha 2(I)s, running slower than the alpha 2(I) chain on electrophoresis. The extension was shown to be on the amino-terminal fragment of pN-alpha (I)s by cleavage with human collagenase, but pepsin was unable to convert pN-alpha 2(I)s to alpha 2(I). Skin collagen was 4-fold more extractable and contained fewer beta-dimers and a lower concentration of cross-linking amino acids than control skin collagen. Electron micrographs of both dermis and bone showed markedly irregular ragged outlines of the collagen fibrils in cross-section, although the patient had no clinical signs of bone disease. Procollagen secreted by her skin fibroblasts in culture showed equal amounts of the normal and abnormal alpha 2(I) chains on pepsin digestion. Before pepsin, the pN-alpha 2(I) component ran as a doublet on electrophoresis; pepsin removed only the normal slower chain. The suspected deletion in pN-alpha 2(I)s was traced by CNBr peptide analysis to the N-propeptide fragment, which behaved on electrophoresis about 15-20 residues smaller than that from the normal pN-alpha 2(I) chain. The simplest genetic explanation is a spontaneous heterozygote in which one normal and one abnormal allele for the pro-alpha 2(I) gene are expressed, the protein defect being a deletion of the junction domain that spans the N-propeptidase cleavage site and the N-telopeptide cross-linking sequence.

Human c-fms proto-oncogene: comparative analysis with an abnormal allele.

The organization of the human c-fms proto-oncogene has been determined and compared with an abnormal allele. The human v-fms homologous genetic sequences are dispersed discontinuously and colinearly with the viral oncogene over a DNA region of ca. 32 kilobase pairs. The abnormal c-fms locus contains a small deletion in its 3' portion. DNA sequencing analysis indicated that it was 426 base pairs in size and located in close proximity to a putative c-fms exon.

Human c-fms proto-oncogene: comparative analysis with an abnormal allele.

The organization of the human c-fms proto-oncogene has been determined and compared with an abnormal allele. The human v-fms homologous genetic sequences are dispersed discontinuously and colinearly with the viral oncogene over a DNA region of ca. 32 kilobase pairs. The abnormal c-fms locus contains a small deletion in its 3' portion. DNA sequencing analysis indicated that it was 426 base pairs in size and located in close proximity to a putative c-fms exon.

Genetic epidemiology of breast cancer: segregation analysis of 200 Danish pedigrees.

An investigation of the genetic epidemiology of breast cancer involving complex segregation analysis of 200 breast cancer pedigrees of Danish extraction is presented. The observed distribution of breast cancer is compatible with transmission of an autosomal-dominant gene with no evidence for residual family resemblance. The gene frequency of the abnormal allele is 0.00756, and the displacement between the homozygous genotype means is 1.695. The gene frequency accounts for a significant proportion of breast cancer in young women, whereas by an advanced age a majority (87%) of affected women are phenocopies. Genetic modeling of other breast cancer families and results of linkage studies are reviewed.

Molecular Genetic Approaches to the Study of the Nervous System pp. 202–214

Disorders primarily affecting the nervous system comprise approximately one third of all established Mendelian genetic diseases in man. Recombinant DNA technology provides new approaches to the diagnosis and elucidation of the molecular pathology of these disorders. For a small but increasing number of disorders the DNA sequence coding for the involved protein has been used to define the precise molecular defect. An example is the Lesch-Nyhan syndrome. In many other situations, DNA fragments located near to the mutant gene can be used in family linkage studies to determine who is likely to have inherited the abnormal allele(s). Examples include Duchenne muscular dystrophy, Huntington's disease, and phenylketonuria. This technology offers unique opportunities to investigate the function of the nervous system in health and disease and will have a major impact on the neurosciences and the practice of clinical neurology.

Molecular genetic approaches to the study of the nervous system.

Disorders primarily affecting the nervous system comprise approximately one third of all established Mendelian genetic diseases in man. Recombinant DNA technology provides new approaches to the diagnosis and elucidation of the molecular pathology of these disorders. For a small but increasing number of disorders the DNA sequence coding for the involved protein has been used to define the precise molecular defect. An example is the Lesch-Nyhan syndrome. In many other situations, DNA fragments located near to the mutant gene can be used in family linkage studies to determine who is likely to have inherited the abnormal allele(s). Examples include Duchenne muscular dystrophy, Huntington's disease, and phenylketonuria. This technology offers unique opportunities to investigate the function of the nervous system in health and disease and will have a major impact on the neurosciences and the practice of clinical neurology.

Relationships between trehalose metabolism and maltose utilization in Saccharomyces cerevisiae

A specific deficiency in UDPG-linked trehalose-6-phosphate synthase in the yeast, Saccharomyces cerevisiae has been associated with a single nuclear gene, sst1. Strains bearing this abnormal allele lacked the capacity to accumulate trehalose during growth on glucose or galactose medium or when incubated with glucose in nonproliferating conditions. However, sst1 strains still exhibited trehalose accumulation during growth on maltose medium, provided they contained a gene for maltose fermentation (MAL gene). Introduction of a constitutive MAL (c) gene into an sst1 strain rendered the strain capable of accumulating trehalose during growth on glucose medium, but did not restore the normal capacity to convert glucose to trehalose in nonproliferating conditions. Different systems, I and II, of trehalose accumulation are proposed. System I would require the UPDG-linked synthase, whereas system II, which is normally specific for maltose, would utilize a different enzyme. It is unlikely that system II produces trehalose by trans-glucosylation, since it converted glucose to trehalose in MAL (c) sst1 strains. The results indicate that maltose specifically induces the production of the MAL gene-product, which, in turn, would stimulate the formation (or activation) of system II.

A new form of nucleoside phosphorylase deficiency in two brothers with defective T-cell function

Two brothers, age 9 and 11, respectively, have marked deficiency of nucleoside phosphorylase associated with defective T-cell function and normal B-cell function. Unlike the previously described five patients with this syndrome, each of these children has sufficient NP catalytic activity in their red blood cells (below 1% of the normal level) to be visualized after electrophoresis and staining for the enzyme. Their healthy sibling has normal NP activity and a normal isozyme pattern. The nonconsanguineous parents have about half-normal NP activity, but their electrophoretic patterns differ from each other's and from those of their affected children. These findings are consistent with genetic heterogeneity at the NP structural gene locus, resulting in compound heterozygosity for two different abnormal alleles.

Congenital nonspherocytic hemolytic anemia associated with glucosephosphate isomerase deficiency: variant Paderborn.

The deficient red cell enzyme glucosephosphate isomerase (GPI) was characterized in a patient of German origin who had already been described, with congenital nonspherocytic hemolytic anemia, and in his heterozygous parents. The variant enzyme differs from the known GPI variant enzyme differs from the known GPI variants by the electrophoretic mobility, the thermal stability, and the leukocyte activity. No differences are found between normal GPI and the variant regarding the affinity to fructose-6-phosphate, the pH optimum and the thermal optimum. Since the electrophoretic pattern and the properties of the parenteral GPI are identical the propositus seems to be homozygous for an abnormal allele and not double-heterozygous as some other cases with GPI deficiency are. Recently, immunological studies have shown that the variant differs from other similar variants. According to the birthplace of the patient the variant is called "Paderborn".

The social effect of Huntington's chorea on reproductive effectiveness.

An attempt has been made to account for the observed departures from a model of a simple single-locus inheritance in Huntington's Chorea. It is postulated that an indirect effect of the abnormal allele lies in its social effects on individuals in the family group whether they bear the allele or not. This acts by influencing their mate-finding and reproductive behaviour so as to produce the observed statistical anomalies.

Glucose phosphate isomerase deficiency with hereditary hemolytic anemia in a Spanish family: Clinical and familial studies

A new case of glucose phosphate isomerase deficiency associated with cogenital nonspherocytic hemolytic anemia is described in a 12-year-old girl of Spanish origin. The parents exhibited erythrocyte glucose phosphate isomerase activity between 50 and 60% of normal. The enzyme of the propositus had normal Michaelis-Menten constants both for F-6-P and G-6-P, but abnormal pH optimum and decreased heat stability at 48 degrees C. On starch-gel electrophoresis the father's enzyme was normal but the mother's showed a cathodic migrating band in addition to the normal one. The enzyme from the propositus exhibited only one band with cathodal mobility of 116% of the main band found in normal subjects. It is postulated that the propositus is double heterozygous for two abnormal alleles, and the mother contributes a mutant allele with abnormal electrophoretic mobility and thermolability at 48 degrees C whereas the father contributes an allele without enzymatic activity.

A NEW VARIANT OF GLUCOSEPHOSPHATE ISOMERASE (GPI) DEFICIENCY WITH CONGENITAL HEMOLYTIC ANEMIA

A new variant of red cell GPI deficiency (Type Nordhorn) with congenital nonspherocytic hemolytic anemia is described. The propositus suffers since birth from a severe anemia. GPI activity is decreased to 22% of the normal. The parents exhibit activities between 36 and 47 %. The thermal stability of the mutant enzyme is decreased in the propositus and in all affected maternal relatives. The propositus is not homozygous, but double-heterozygous for two abnormal alleles. The heterozygous mother contributes an allele which produces a thermolabile enzyme of decreased activity and abnormal electrophoretic mobility, whereas the father contributes an inactive gene product. The enzyme defect becomes also manifest in the leucocytes of the propositus. The thermolability is also evident in the leucolysates of the mother. Compared with erythrocyte populations of similar mean cell age the rate of red cell glycolysis is reduced in the propositus. A premature inactivation of the enzyme during maturation of the erythrocytes is suggested.

Glucose phosphate isomerase deficiency with congenital nonspherocytic hemolytic anemia: a new variant (type Nordhorn). I. Clinical and genetic studies.

Extract: A new variant of glucose phosphate isomerase (GPI) deficiency (type Nordhorn) associated with congenital nonspherocytic hemolytic anemia is described. The propositus, an 18-month-old boy of German origin, has suffered since birth from a severe to moderate macrocytic anemia, which is characterized by low mean corpuscular hemoglobin concentration (28%), high reticulocytosis (45—60%), normal osmotic fragility, type I autohemolysis, and short erythrocyte life-span (51Cr t1/2 = 2 days). With the exception of GPI, the activities of most erythrocyte enzymes are increased. GPI activity is decreased to 22% of the normal. The father and mother exhibit GPI activities between 36% and 47% of normal. No difference is demonstrable between the enzyme of the propositus and normal subjects concerning Michaelis-Menten constant for fructose 6-phosphate, pH optimum, and thermal optimum. The stability of the enzyme is decreased in the propositus and in all affected maternal relatives. The enzyme of the paternal relatives is stable. On starch-gel electrophoresis the enzyme of the father is normal (three bands). In the hemolysate of the mother a fourth cathodally migrating band is demonstrable in addition to the three normal bands. The propositus exhibits only one band with a cathodal mobility of 132% of the main band of normal subjects. It is suggested that the propositus is double heterozygous for two abnormal alleles. The heterozygote mother contributes an allele which produces a thermolabile enzyme of decreased activity and abnormal electrophoretic mobility, whereas the father contributes an allele without enzymatic activity.The enzyme defect is also manifest in the leukocytes of the propositus (39% of normal activity). The thermolability is evident in the leukolysates of the propositus and in those of his mother.When erythrocyte glucose consumption and lactate formation are compared with nonenzymopenic, reticulocyte-rich blood, which has no metabolic defect, the rate of glycolysis is markedly impaired in the propositus. Glucose 6-phosphate, the substrate before the defect, accumulates fourfold and probably inhibits hexokinase, and consequently glycolysis. Compared with erythrocyte populations of similar mean cell age, the concentrations of ATP and 2,3-diphosphoglycerate are decreased. After separation of young from old cells the defect becomes more evident in the older population. Premature inactivation of the enzyme during maturation is suggested.Speculation: Many so-called “homozygous states” of inherited enzyme defect: could be double heterozygous as well. Double heterozygosity may partially explain the clinical heterogeneity of the “homozygous” manifestation, and the lack of correlation between residual enzyme activity and clinical expression in many inborn errors of metabolism. In double heterozygotes with glucose phosphate isomerase deficiency, a premature inactivation of the enzyme during maturation of the erythrocytes may be the reason for metabolic impairment of the celIs, followed by premature hemolysis.

The Characterisation of Individuals with Respect to Wilson's Disease

In the case of heredo-familial diseases it is desirable to identify the abnormal genotype, the homozygously abnormal individual, if possible while still asymptomatic, and the carrier of the abnormal gene or allele, the heterozygote.So far as Wilson's disease is concerned, it is possible to diagnose individuals as presymptomatic homozygotes by finding Kayser-Fleischer corneal rings on slit-lamp microscopy, or by demonstrating increased liver-copper on needle biopsy.False-negative results are common, however, and more reliable identification of the presymptomatic homozygote as well as the heterozygote can be achieved by studies of the physiology of copper, using tracer doses of radioactive copper, 67copper, which has a physical half life of about 61 hours. Using this method it can be shown:1. That there is prolonged retention of copper in the whole body in both homozygotes and heterozygotes, the former showing more prolonged retention than the latter.2. In both there is retention of copper in the liver, again more marked in the homozygote than in the heterozygote.3. There is decreased intestinal excretion of copper in both cases as manifested by decreased biliary radiocopper and decreased stool radiocopper, and again this is most marked in the homozygote.4. Urinary excretion of radiocopper is usually increased significantly in the homozygote, but is usually normal or only very slightly increased in the heterozygote.5. The additional finding of impaired ceruloplasmin biosynthesis is sufficient usually to distinguish with certainty between the presymptomatic homozygote and the heterozygote.

Detection of the carrier state for classic hemophilia.

Carriers of classic hemophilia may be detected by comparison of levels of antihemophilic factor as measured by clot-promoting assay (i.e., functionally active factor) and by quantitative immunoelectrophoresis (i.e., both functionally active and inactive factor). This technic has detected over 90 per cent of a group of known carriers. In addition, when applied to a group of 18 daughters of known carriers of hemophilia, the technic detected the carrier state in nine of these. In a second group of women, the mothers of hemophilic sons with no family history of the disorder, seven of 10 had evidence of the carrier state. Study of other members of these families suggested that mutation to the abnormal allele occurred on the X chromosome from which either the hemophilic patient or his mother arose.

Detection of the carrier of Wilson's disease

SUMMARYWhole-body counting over a three- to four-week period following the intravenous administration of copper 67 in 11 normal volunteers, 2 neurological control patients, 7 control subjects with cirrhosis, and 10 homozygotes and 7 heterozygotes of Wilson9s disease showed that whole-body retention of radio-copper was prolonged in the wilsonian subjects, both homozygous and heterozygous, and in cirrhotic patients with ascites or hepatocellular failure or both. If the latter can be excluded, prolonged whole-body retention of radiocopper serves to identify the presence of the abnormal gene or allele of Wilson9s disease. Because of overlap, it is not possible to distinguish the heterozygote from the homozygote by whole-body counting alone. External probe counting over the liver and muscle, carried out in 5 control subjects, 8 homozygotes, and 5 heterozygotes, revealed abnormal hepatic uptake with little apparent release of radiocopper and usually evident uptake in muscle in the homozygotes and reasonably normal hepatic uptake with delayed release and no apparent muscle uptake in the heterozygotes, compared with the control subjects. It appears that external monitoring of hepatic and muscle radioactivity, in addition to whole-body turnover measurements after intravenous copper 67, permits more accurate determination of the genetic status of individuals in respect to Wilson9s disease.