A CCG repeat polymorphism adjacent to the CAG repeat in the Huntington disease gene: implications for diagnostic accuracy and predictive testing

STUDY HYPOTHESIS: Concentrated aqueous solutions of hydroxocobalamin (OHCob) are given intravenously for the treatment of cyanide poisoning. Because OHCob solutions are intensely red and have peak light absorptions at 352 nm and 525 nm, we investigated whether the presence of OHCob in serum would interfere with various automated, colorimetric chemistry measurements. DESIGN: Selected serum chemistry colorimetric measurements were compared in seven patients, using their own serum as control, with serum containing OHCob at the following concentrations: 100 mg/L, 500 mg/L, and 1,000 mg/L. These concentrations are in the range achieved with therapeutic doses of OHCob when given for cyanide poisoning. MEASUREMENTS AND MAIN RESULTS: Statistically significant alterations in serum values for aspartate aminotransferase, total bilirubin, creatinine, magnesium, and iron were seen in the presence of OHCob. CONCLUSION: The presence of OHCob in serum interferes with several chemistry methodologies, and such interference should be anticipated when this antidote is used.     

Sequence analysis of the CCG polymorphic region adjacent to the CAG triplet repeat of the HD gene in normal and HD chromosomes

The CAG expansion responsible for Huntington's disease (HD) is followed by an adjacent polymorphic CCG repeat region which may interfere with a PCR based diagnosis. We have sequenced this region in 52 unrelated HD patients, from both normal and HD chromosomes. Fifty percent of the normal alleles were (CCG)7(CCT)2, 48% (CCG)10(CCT)2, and 2% (CCG)7(CCT)3. In contrast (CCG)7(CCT)2 was found in 85% of the HD alleles which represents significant linkage disequilibrium with the HD mutation.     

Limited expansion of the (CAG)n repeat of the Huntington gene: a premutation (?)

Pantoprazole is a specific inhibitor of the H+/K(+)-ATPase of the gastric parietal cell. The dose-dependency of a range of pantoprazole pharmacokinetic characteristics was studied. Twelve healthy male subjects were given 10, 20, 40 and 80 mg pantoprazole intravenously according to a randomized, single blind, 4-period change-over scheme. The area under the concentration vs time curve (AUC) and the maximum serum concentration (Cmax) showed a linear increase in line with the dose. Apparent volume of distribution (Vd area), clearance (Cl) and terminal half-life (t1/2) were independent of the dose. The dose-independent elimination of pantoprazole was attributed to the lack of interaction of the drug with cytochrome P450. In clinical practice, a good predictable response, as well as a low potential for interaction with other drugs might be expected.     

Sequence and polymorphism analysis of the murine gene encoding histidyl-tRNA synthetase

The transition from the partial to the total loss of teeth is characterized by the presence of a reduced number of remaining teeth, on a single maxilla or on both of them, which don't provide optimum conditions for the conjunct or composite prosthetics. Its extraction contravene to the biological principle. Its preservation and utilisation involves a series of difficulties, which the dental surgeon must known and surpass within the frame of the prosthetic therapy. The secondary dental malposition, the absence or the reduction of the intercadic dental contacts, accompanying the mandibular cranial malrelations, all with implications in the oro-facial esthetic modification, require specific, complex interventions, before the definitive prosthetics. Upon the basis of a 15 years practical experience, the work presents a series of such clinical cases, the applied therapy and the outcomes also.     

TGFbeta-inducible early gene (TIEG) also codes for early growth response alpha (EGRalpha): evidence of multiple transcripts from alternate promoters

OBJECTIVE: To describe changes in antirheumatic medication use by patients with rheumatoid arthritis (RA) over the 15 years 1981 to 1996. METHODS: Medication use was ascertained every 6 months by mailed Health Assessment Questionnaire in a cohort of patients recruited from the local community (n = 305; mean duration of RA at study entry 14.2 yrs). Patients were treated by 53 rheumatologists and over 200 other physicians during the study. The proportions of patients treated with nonsteroidal antiinflammatory drugs (NSAID), disease modifying antirheumatic drugs (DMARD), prednisone, intraarticular corticosteroids, and analgesics were determined in serial cross sectional analyses, and trends in medication use over time were analyzed using linear regression. RESULTS: From 1981 to 1996, the proportion of patients treated with DMARD increased from 32 to 47% (average increase 1.06% each year; p < 0.0001), while the proportion treated with NSAID decreased from 86 to 76% (average decrease 0.57% each year; p < 0.0001). The proportion of patients treated with prednisone remained between 30 and 40%, with a trend toward increasing use over time (average increase 0.2% each year; p = 0.05). In contrast, the proportion treated with intraarticular corticosteroids decreased from 14.4 to 6.7% (average decrease 0.46% each year; p < 0.0001). In 1996, the most prevalent patterns of medication use were the use of NSAID alone (24.4%), use of an NSAID and DMARD (16.3%), and use of an NSAID, DMARD, and prednisone (12.2%). Use of an NSAID as the only antirheumatic medication decreased over time, and the use of DMARD in combination with other medications increased. CONCLUSION: The proportion of patients with RA treated with DMARD increased substantially from 1981 to 1996. This change in practice occurred during the time in which the concept of inverting the traditional therapeutic pyramid became popular, and may reflect a translation among clinicians of the philosophy of "early DMARD use" to "consistent DMARD use," even among patients with RA of moderate or longstanding duration.     

Impact of apo(a) length polymorphism and the control of plasma Lp(a) concentrations: evidence for a threshold effect

Plasma lipoprotein(a) [Lp(a)] levels are believed to be controlled predominantly by the apolipoprotein(a) [APO(a)] gene, which encodes the apo(a) glycoprotein, a key constituent of the Lp(a) particle. Previously, it has been accepted that the plasma Lp(a) level is inversely proportional to apo(a) length. To examine this relationship in greater detail, 1500 unrelated, homogeneous (sex, race, age, plasma lipids) subjects were studied, from which 769 were identified with a single-expressing APO(a) allele. A bimodal frequency distribution of apo(a) isoforms was observed. As expected, there was a general inverse relationship between apo(a) isoform size and Lp(a) level. However, when groups with equivalent single-expressing apo(a) isoforms were studied, it was clear that although smaller isoforms were associated on average with higher levels, they were also associated with the greatest variability in level. After logarithmic transformation of Lp(a) data, the overall contribution of the apo(a) length polymorphism was calculated to be 38%. However, in subjects with apo(a) isoforms of 20 K-4 repeats, the corresponding contribution is 10%. We conclude that the contribution of the apo(a) isoform size to the control of plasma Lp(a) level is considerably lower than previously calculated, because the variability in plasma Lp(a) concentration is not uniform across the apo(a) size spectrum.     

No evidence for linkage of a novel CA repeat polymorphism for apoptosis antigen 1 (APO-1 or fas) with type I diabetes in a Caucasian population

Abstract DNA typing of four tetrameric repeat loci (HUMVWA, HUMTH0I, D21SII and HPRT) was carried out in a Chinese Han population from Shanghai (East China) and one from Guangzhou (South-East China) using a quadruplex PCR amplification and detection of the fluorescent-labeled alleles on the ALF DNA sequencer. All loci were in accordance with Hardy-Weinberg equilibrium except for D21S11 in the Guangzhou population. A test for population differentiation showed no statistical difference in the allele frequency distribution between the two populations. Comparison of the allele frequency data with other Chinese Han populations from North and South-West China for the STR loci HUMVWA and HUMTH01 revealed heterogeneity between Northern Chinese Han and Southern Chinese Han, which is in accordance with previous studies on the basis of protein markers.     

Heterogeneity of DM kinase repeat expansion in different fetal tissues and further expansion during cell proliferation in vitro: evidence for a casual involvement of methyl-directed DNA mismatch repair in triplet repeat stability

We have analysed the mitotic behaviour of expanded CTG repeats in somatic tissues and cultured somatic cells from myotonic dystrophy (DM) fetuses using indirect and direct methods. Heterogeneity of expansions between fetal tissues was demonstrated in a 16 week old fetus whereas there was no evidence for such a somatic heterogeneity in a 13 week old fetus. Dilution plating of cultured cells from an adult patient and a fetus resulted in isolation of clones showing single expanded restriction fragments when the donor showed a heterogeneous smear of expansions or a single expanded fragment. During proliferation in vitro to 45 doublings, DM cells experienced highly synchronous further repeat expansion which first became evident at approximately 15 cell generations and reached a plateau of maximum expansion at approximately 200 days. When mathematically expressed as a function of culture time the dynamics of expansion of restriction fragments followed a sigmoid curve. This unstable behaviour of CTG repeat expansions in DM was compared to the mitotically stable patterns of full mutation in fragile X fetal tissues and led to the hypothesis that methylation of CpGs within the repeat sequence is a stabilizing factor of largely expanded CGG and GCC repeats allowing for efficient methyl-directed strand-specific DNA mismatch repair.     

Compensation for a gene trap mutation in the murine microtubule-associated protein 4 locus by alternative polyadenylation and alternative splicing

One of the features expected of the gene trap approach is the functional mutation of a gene, allowing its loss-of-function phenotype analysis. We have mutated the murine microtubule-associated protein 4 (MAP-4) locus by inserting a splice-acceptor gene trap construct. Because the MAP-4 gene has been cloned, sufficient information is available to investigate the efficiency of the gene trap insertion in disrupting the protein-coding region. The fusion mRNA contains the first 905 bases of the MAP-4 mRNA and is expected to code for a truncated, nonfunctional MAP-4 protein missing, among others, the microtubule-binding domain. Activity of the lacZ marker gene of the gene trap construct was observed in all tissues throughout development and in all cells examined in adult animals. However, some cells and tissues showed higher levels of activity than others: for example, blood vessel endothelium, heart, aspects of the developing nervous system, surface ectoderm of embryonic day 11.5 embryos, and the ependymal layer and blood vessel endothelium in adult brain. MAP-4 binds to microtubules and is thought to modulate their stability. It is expressed differentially in different tissues as 5.5-kb, 6.5-kb, 8-kb, 9-kb, and 10-kb mRNA species from a single copy gene in mice. Northern hybridization with a 5', MAP-4-specific probe revealed a 3.3-kb splice variant, which has not been described previously, that was expressed as the most abundant MAP-4 mRNA species in the brain but not in other tissues. Mice homozygous for the reported gene trap insertion in the MAP-4 locus (MAP-4gt/gt) are viable and appear to be phenotypically normal. They exhibited normal levels of all MAP-4 mRNA species in brain and kidney, showing that the simian virus 40-polyadenylation signal of the gene trap construct was ignored and also showing compensation for the gene trap insertion by splicing around the gene trap construct.     

Ethical, social and legal issues in Huntington disease: the nurse's role

The nurse's role will be discussed in relation to the issues which may present as the result of our ability to use predictive tests for neurodegenerative disease. Huntington disease is an autosomal dominant inherited disease, characterised by emotional problems, abnormalities of movement and dementia. The disease is slowly progressive leading to a severely debilitated state and finally death in ten to twenty years. In 1983, DNA testing became available for persons at risk for Huntington disease and for confirmation of diagnosis for those showing symptoms. The availability of testing presents many ethical, social and legal issues for persons at risk, health care professionals and other segments of society. This paper will briefly review the genetic transmission and profession of Huntington disease. It will outline some of the benefits as well as some of the risks and problems DNA testing presents.     

A highly informative CA/GT repeat polymorphism in intron 38 of the human neurofibromatosis type 1 (NF1) gene

We describe a polymorphic microsatellite in intron 38 of the neurofibromatosis type 1 (NF1) gene. The microsatellite consists of a CA/GT dinucleotide repeat detecting 8 alleles; it has a heterozygosity of 82%.     

Analysis of (CAG)n size heterogeneity in somatic and sperm cell DNA from intermediate and expanded Huntington disease gene carriers

Various kinds of lipophilic peptides were prepared by acylation of an alpha-helical peptide, mastoparan, to investigate the effects of acyl groups on the interaction of peptides with phospholipid membranes. alpha-Helicity of the peptides was increased by introduction of long acyl groups. Acyl peptides showed different membrane-perturbation activities for neutral and acidic phospholipid vesicles, whereas a peptide with a dialkycarbamoyl group always exhibited a strong activity. High hemolytic activities were observed for the peptides with long acyls (single or double chain). These results indicate that lipophilic groups introduced to mastoparan contribute greatly to the interaction of the peptide with phospholipid membranes with lengthening of the acyl chain and that the structural character of the lipophilic group also influences the conformation of the peptide.     

DNA-dependent kinase (p350) as a candidate gene for the murine SCID defect

Severe combined immunodeficient (SCID) mice are deficient in a recombination process utilized in both DNA double-strand break repair and in V(D)J recombination. The phenotype of these mice involves both cellular hypersensitivity to ionizing radiation and a lack of B and T cell immunity. The catalytic subunit of DNA-dependent protein kinase, p350, was identified as a strong candidate for the murine gene SCID. Both p350 and a gene complementing the SCID defect colocalize to human chromosome 8q11. Chromosomal fragments expressing p350 complement the SCID phenotype, and p350 protein levels are greatly reduced in cells derived from SCID mice compared to cells from wild-type mice.     

Machado-Joseph disease: cerebellar ataxia and autonomic dysfunction in a patient with the shortest known expanded allele (56 CAG repeat units) of the MJD1 gene

We describe an unusual case of a patient with Machado-Joseph disease (MJD) who showed autonomic dysfunctions in addition to cerebellar ataxia. The number of CAG repeat units in the expanded allele of the MJD1 gene of the patient is smaller (56 CAG repeat units) than all previously reported numbers of CAG repeat units in expanded alleles. Thus, the findings in this patient indicate that the clinical features of MJD cover a wider spectrum than previously thought.