NEW YORK — Researchers have identified two genes, making it clear why only some women are likely to conceive twins and others don’t, in a recent study.
With these results, the team hopes to develop a genetic test to identify women at risk for this condition.
“There’s an enormous interest in twins, and in why some women have twins while others don’t,” said one of the researchers Dorret Boomsma, biological psychologist at Vrije Universiteit (VU) Amsterdam in the Netherlands.
The genes behind this theory have always been the mystery. Although it is known that if a woman’s female relatives have non-identical twins, she is more likely to give birth to twins herself.
“The question is very simple, and our research shows for the first time that we can identify genetic variants that contribute to this likelihood,” Boomsma noted in the findings appeared in the journal American Journal of Human Genetics.
For the study, the international team of researchers aggregated genetic data from twin databases in the Netherlands, Australia, and the US.
The sample totaled 1,980 mothers of fraternal (commonly known as non-identical) twins conceived without fertility treatments and 12,953 controls.
The researchers were looking for genetic variants, shared by mothers with twins that showed a different frequency from those in the control groups.
Once the researchers had identified a handful of candidates, they sent the results to collaborators in Iceland, who crunched the numbers on their own set of 3,597 mothers with twins and 297,348 controls.
Two of the gene variants were replicated in the Icelandic cohort, appearing more often in the mothers with fraternal twins conceived without fertility treatments.
One of the variants, located near a gene called FSHB, is associated with higher levels of follicle-stimulating hormone (FSH).
The second genetic variant, in a gene called SMAD3 involved in cell signalling, probably plays a role in how the ovaries respond to FSH, Cornelis Lambalk, gynecologist at VU Medical Centre Amsterdam, said.
If a woman produces an average level of FSH, but her ovaries are more sensitive to the hormone, she may still release multiple eggs at a time.
“This genetic variant is totally novel and hadn’t been shown before as a candidate gene for twinning,” first author on the study Hamdi Mbarek, geneticist at VU Amsterdam, noted.
1 killed, 2 injured in Dhading truck mishap
DHADING — One person was killed while two other seriously injured when a truck fell from Hugdi Khola Bridge in Rorang-10, Benighat along the Prithvi Highway on Wednesday.
The truck (Na 5 Kha 1568) en-route to Chitwan from Kathmandu fell off the bridge to Hugdi Khola (river) on Wednesday afternoon.
The deceased has been identified as 23-year-old Sher Bahadur Magar,23, of Madhya Bindu Municipality-10, according to police. Magar died on the course of treatment at a Malekhu-based hospital, informed Area Police Office, Gajuri.
Those injured in the incident are Manoj Ale 25, of Arunkhola, Nawalparasi and Megh Bahadur Gharti of Sitakganga Municipality in Arghakhanchi district have been sent to Kathmandu for further medical treatment.Follow @gorkhapost