Elma Scheibel

Bio: Elma Scheibel is an academic researcher from Copenhagen University Hospital. The author has contributed to research in topics: Haemophilia A & Prenatal diagnosis. The author has an hindex of 5, co-authored 7 publications receiving 399 citations.

Absence of correlation between X chromosome inactivation pattern and plasma concentration of factor VIII and factor IX in carriers of haemophilia A and B.

Abstract: Haemophilia A and B are X-linked disorders which are due to a reduced activity of coagulation factor VIII or IX, respectively. Female carriers have a wide range of plasma concentration of factor VIII or factor IX, and may in rare cases have an affected phenotype. In order to investigate if this variation is related to X chromosome inactivation, we determined the X inactivation pattern in 31 haemophilia A and 15 haemophilia B carriers, using a PCR in the androgen receptor locus in blood DNA. Seven of the haemophilia A carriers and none of the haemophilia B carriers had a skewed pattern (> or =80:20). One of the skewed haemophilia A carriers had a low plasma concentration of factor VIII (0.15 U/ml), but the remaining 6 carriers did not differ in factor VIII concentration from that of carriers with a random X inactivation pattern. One carrier with a high factor VIII concentration (2.0 U/ml) did not have a skewed pattern. Similarly, for the haemophilia B carriers, there was no tendency to a more skewed X inactivation pattern in the carriers with low or high factor IX concentrations. In addition, we analysed a female with haemophilia B who was heterozygous for the mutation R180W in the factor IX gene. She had a random X chromosome inactivation pattern. We conclude that the wide range in plasma concentration of factor VIII and factor IX in haemophilia A and B carriers cannot in general be explained by the X chromosome inactivation pattern in peripheral blood cells.

Detection of ten new mutations by screening the gene encoding factor IX of Danish hemophilia B patients.

Abstract: Hemophilia B is caused by a wide range of mutations. In order to characterize the mutations among patients in Denmark, we have systematically screened the entire coding region, the promoter region and exon flanking sequences of the gene encoding factor IX using single strand conformation and heteroduplex analyses. Patients from 32 different families were examined, and point mutations (23 different) were found in all of them. Ten of the mutations have not been reported by others; they include a splice site mutation, a single base pair deletion, and missense mutations. Notably, the study contains a female patient and a previously described Leyden mutation. In ten families with sporadic cases of hemophilia B, all 10 mothers were found to be carriers. The origin of two of these mutations was established.

Alpha interferon therapy in Danish haemophiliac patients with chronic hepatitis C: results of a randomized controlled open label study comparing two different maintenance regimens following standard interferon-alpha-2b treatment

Abstract: Following a survey among all Danish haemophiliac patients 49 HIV-negative patients with chronic hepatitis C were offered enrollment in a randomized controlled open label study comparing two different maintenance regimens following standard interferon-alpha-2b treatment. Dose modifications and treatment discontinuation were based upon changes in transaminase levels. Forty-seven patients enrolled received 3 MU of alpha interferon thrice weekly (TIW) for 3 months. Twenty-six nonresponders had their dose increased to 6 MU TIW for an additional 3 months, while 21 responding patients continued on 3 MU TIW. At 6 months, 25 patients with a complete or a partial biochemical response were randomly allocated to either a fixed dose regimen (13 patients) (3 or 6 MU thrice weekly) or an individualized dose regimen (12 patients) tapering interferon dose from 3 or 6 MU by one-third every 2 months if transaminases were persistently normal. The remaining 22 biochemical nonresponders were followed for an additional 6 months without further treatment. After 12 months of treatment, 18 patients (38%) had a virological response, irrespective of regimen, and seven patients (16%) had a sustained virological and biochemical response after 6 months of follow up. Overall, the individualized treatment regimen did not seem to offer any advantage over the fixed dose regimen. The response to alpha interferon treatment in Danish haemophiliac patients with chronic hepatitis C immediately after treatment is comparable to that obtained in previous studies among nonhaemophiliacs. However, a sustained virological and biochemical response was seen in only 16% of treatment patients.

The origins, patterns and implications of human spontaneous mutation

Abstract: The germline mutation rate in human males, especially older males, is generally much higher than in females, mainly because in males there are many more germ-cell divisions. However, there are some exceptions and many variations. Base substitutions, insertion-deletions, repeat expansions and chromosomal changes each follow different rules. Evidence from evolutionary sequence data indicates that the overall rate of deleterious mutation may be high enough to have a large effect on human well-being. But there are ways in which the impact of deleterious mutations can be mitigated.

WFH Guidelines for the Management of Hemophilia, 3rd edition

Abstract: Alok Srivastava 1 | Elena Santagostino 2 | Alison Dougall 3 | Steve Kitchen 4 | Megan Sutherland 5 | Steven W. Pipe 6 | Manuel Carcao 7 | Johnny Mahlangu 8 | Margaret V. Ragni 9 | Jerzy Windyga 10 | Adolfo Llinás 11 | Nicholas J. Goddard 12 | Richa Mohan 13 | Pradeep M. Poonnoose 14 | Brian M. Feldman 15 | Sandra Zelman Lewis 16 | H. Marijke van den Berg 17 | Glenn F. Pierce 18 | on behalf of the WFH Guidelines for the Management of Hemophilia panelists and co-authors*

The high spontaneous mutation rate: Is it a health risk?

Abstract: The human mutation rate for base substitutions is much higher in males than in females and increases with paternal age. This effect is mainly, if not entirely, due to the large number of cell divisions in the male germ line. The mutation-rate increase is considerably greater than expected if the mutation rate were simply proportional to the number of cell divisions. In contrast, those mutations that are small deletions or rearrangements do not show the paternal age effect. The observed increase with the age of the father in the incidence of children with different dominant mutations is variable, presumably the result of different mixtures of base substitutions and deletions. In Drosophila, the rate of mutations causing minor deleterious effects is estimated to be about one new mutation per zygote. Because of a larger number of genes and a much larger amount of DNA, the human rate is presumably higher. Recently, the Drosophila data have been reanalyzed and the mutation-rate estimate questioned, but I believe that the totality of evidence supports the original conclusion. The most reasonable way in which a species can cope with a high mutation rate is by quasi-truncation selection, whereby a number of mutant genes are eliminated by one “genetic death.”