WEEKLY UPDATE: March 2, 2020
SUMMARY: Three genetic variants are associated with spontaneous dizygotic twinning.
OVERVIEW: If you walk past 30 people in the United States, the odds are good that at least one of them will have a twin brother or sister. Travel to many areas of Asia and that number rockets to 70 people, but visit the west African country of Benin and you may only need to walk past 16 people to see a twin. Twins can either be monozygotic (identical) or dizygotic (fraternal), but the genetic factors that may influence a woman’s chances of having either type are not well understood. This study examined the genetic data of nearly 15,000 mothers of European ancestry to identify variants associated with dizygotic, or fraternal, twinning. The study found 3 variants that together increase a woman’s odds of delivering twins by over 50%. One is located near a gene that produces FSH, a hormone involved in the development of eggs inside a woman’s ovaries.
DID YOU KNOW? Women over the age of 30 have an increased chance of giving birth to twins. This is likely because levels of FSH increase as women age. [SOURCE]
ANALYZED VARIANTS: rs11031006, rs17293443, rs12064669