Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

American research finds twins more likely to have premature menopause

25.10.2006
Twins are more likely to have a premature menopause than other women, according to research published on line today (Wednesday 25 October) in Europe’s leading reproductive medicine journal, Human Reproduction[1] .

In a study of more than 800 Australian and UK twin pairs, lead by Dr Roger Gosden, Professor of Reproductive Biology at Weill Medical College of Cornell University in New York, premature ovarian failure was between three and five times greater when measured at age 40 and age 45 than in the general population. Ovarian failure before the age of 40 normally affects only around one woman in a hundred.

The finding applied whether or not the twins were identical (monozygotic) or non-identical (dizygotic). It confirms tentative previous data on premature ovarian failure (POF) in non-identical twins, but it is the first time it has been established in identical twins as well.

However, there were twins in the study where the menopausal ages were very different – a disparity of more than 20 years in a few cases. It was disparity in menopausal ages among twins that led to this study. First, it was prompted by the recent case of ovarian transplantation between 24-year-old identical twins at the Infertility Center in St. Louis carried out by this study’s co-author Dr Sherman Silber. One twin had undergone unexplained POF at age 14, but this was reversed through ovarian tissue transplantation from her sister, and she later conceived. Subsequently, several more identical twin pairs came forward for possible treatment and the researchers received anecdotal information about other cases of disparity in menopausal ages among twins.

“It prompted us to test the hypothesis that POF is more prevalent in identical twins than in the general population,” explained Dr Gosden.

They analysed data from 428 twin pairs on the Australian twin register and 404 on the UK twin register who had undergone a natural menopause and compared them with a control group of an ethnically comparable population of 3,483 Dutch women recruited for a breast screening programme, most of whom were post-menopausal with a mean menopausal age of just over 50.

“Our study validates the hypothesis that twins have a statistically significantly higher prevalence of POF than women generally. The differences were large at three to five-fold at both the 40- and 45-year threshold and were similar in both the national registers. The reason that the association between twins and POF has been largely overlooked up to now is probably because POF is still uncommon, even in twins, (3 to 5 in a hundred),” said Dr Gosden.

He said the surprising finding was that POF was just as common in non-identical twins as in identical twins.

“It may be that, contrary to the usual situation of non-identical twins being more common in women past the prime age of fertility (20s), in mothers whose biological clock is running faster than normal and whose ovarian reserve is running low, the likelihood of having twins shifts to an earlier age – to their peak childbearing years. So, even though they are non-identical, one or both twins born to these mothers may be inheriting her tendency to early menopause.”

With identical twins, the explanation for the excess of POF would be different according to Dr Gosden, and was, as yet, unknown and more puzzling. Studies in twins and mother-daughter pairs had shown a strong heritable component for menopausal age, although the genetic factors responsible were still largely unidentified. The current study was consistent with this finding insofar as identical twins had lesser disparities in menopausal age than non-identical twins. In several diseases such as familial breast cancer or Alzheimer’s disease, forms linked with mutations in single genes occur earlier in life than do sporadic cases. So, perhaps, it would not be surprising if identical twins were more synchronised for POF than for later menopause.

“We haven’t been able to make much progress towards understanding the mechanism in identical twins because of lack of suitable animal models. But, there are two possibilities that we may be able to check. First, discordant ovaries could arise if early post-implantation embryos split unequally during the critical period when progenitor germ cells are forming. Then a subnormal number of follicles might form in one twin. Second, there could be competition in the uterus and the stress might encourage abnormalities in the ways the genes needed to make eggs are expressed in the ovaries of each twin. We are not looking for mutations in the DNA sequence, but gene switches, a topic called epigenetics.”

Dr Gosden said that while the great majority of identical and non-identical twins can expect to reach menopause at a similar age to singletons there were clinical implications for a twin with POF whose sibling is still fertile.

“The first option is of ooctye donation for both identical and non-identical twins. For identical twins, in addition, we now have the possibility of ovarian tissue grafting. That might even be considered in some rare cases for non-identical twins if there is a good tissue match.

“This is an important development as, although proportionately rare, the numbers of cases could be substantial in large countries. In the USA, for example, there are 150,000 identical twin pairs in the 20 to 40 age bracket. About 6,000 individuals (4%) will have POF before they are 40 and the data predict a substantial proportion of these will have a sister with a larger ovarian reserve and a likely later menopause.“

(ends)

[1]Prevalence of premature ovarian failure in monozygotic and dizygotic twins. Human Reproduction. doi:10.1093/humrep/del382.

Margaret Willson | alfa
Further information:
http://www.oxfordjournals.org
http://www.eshre.com

Further reports about: Gosden Menopause POF identical non-identical ovarian premature

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>