So they don’t. Instead, they buy a $100 test kit, they each provide a small blood sample and send it off to one of the companies offering fetal genome testing. At the testing lab, they can separate out the mother’s DNA from that of the fetus, both of which are present in the mother’s blood. By comparing the fetal genome to the mother’s and father’s, it’s easy to spot de novo mutations. If a certain gene doesn’t match either the mother or the father’s sequence, it’s mutated.
A few days later the results are back. There are several mismatches detected. Most are benign – they’re not predicted to have any biological effects. But there’s one, a deletion of a few thousand bases in a gene involved in brain development. This deletion is predicted to raise the risk of epilepsy and autism from 1% to 10% apiece. The parents now have a decision to make. The mutation is a one off, it’s not inherited. If they conceive again… roll the dice again… and it’ll be gone. Do they terminate?
Like the adverts say, “Some people disagree with this, but we say there’s only one ...
July 10, 2012
June 26, 2010
There will be an interesting presentation tomorrow at the European Society of Human Reproduction & Embryology. Basically the researcher is going to present on a method for predicting when a woman will hit menopause. This part from the press release is the important bit:
“The results from our study could enable us to make a more realistic assessment of women’s reproductive status many years before they reach menopause. For example, if a 20-year-old woman has a concentration of serum AMH of 2.8 ng/ml [nanograms per millilitre], we estimate that she will become menopausal between 35-38 years old. To the best of our knowledge this is the first prediction of age at menopause that has resulted from a population-based cohort study. We believe that our estimates of ages at menopause based on AMH levels are of sufficient validity to guide medical practitioners in their day-to-day practice, so that they can help women with their family planning.”
By taking blood samples from 266 women, aged 20-49, who had been enrolled in the much larger Tehran Lipid and Glucose Study, Dr Ramezani Tehrani and her colleagues were able to measure the concentrations of a hormone that is produced by cells in women’s ovaries – anti-Mullerian Hormone (AMH). AMH controls the development of follicles in the ovaries, from which oocytes (eggs) develop and it has been suggested that AMH could be used for measuring ovarian function. The researchers took two further blood samples at three yearly intervals, and they also collected information on the women’s socioeconomic background and reproductive history. In addition, the women had physical examinations every three years. The Tehran Lipid and Glucose Study is a prospective study that started in 1998 and is still continuing.
The standard objection to sample size will naturally be brought forth, but if it’s a valid diagnostic I assume it’ll get popular really quickly.
Here are the results:
Dr Ramezani Tehrani was able to use the statistical model to identify AMH levels at different ages that would predict if women were likely to have an early menopause (before the age of 45). She found that, for instance, AMH levels of 4.1 ng/ml or less predicted early menopause in 20-year-olds, AMH levels of 3.3 ng/ml predicted it in 25-year-olds, and AMH levels of 2.4 ng/ml predicted it in 30-year-olds.
In contrast, AMH levels of at least 4.5 ng/ml at the age of 20, 3.8 ngl/ml at 25 and 2.9 ng/ml at 30 all predicted an age at menopause of over 50 years old. The researchers found that the average age at menopause for the women in their study was approximately 52.
Remember this is a presentation at a conference, not a paper. I don’t have much to say about this from a technical perspective. What do I know? But surely this is important from a science-you-can-use perspective.