April 21, 2023
2 min read
Aldasouqi is professor of medicine and chief of the endocrinology division at Michigan State University College of Human Medicine in East Lansing.
Disclosures: Aldasouqi reports serving as a consultant to Abbott Diagnostics.
In the last post, I told the story of two brothers and made some observations about identical twins. It just so happened that the stories on identical twins kept coming.
To recap the story of the two brothers: They were both hospitalized with moderately severe hyperthyroidism due to Graves’ disease. The timeline of their disease has been intriguingly parallel, almost concomitant. They were both discharged and seen in the clinic.
The brothers have encouraged me to share follow-up details of their story as part 2 of this miniseries on identical twins. The story of their clinic visit was as interesting as their hospitalization. The two brothers, wearing similar outfits, swapped the chair and the exam table for their individual case reviews.
Then, a few days ago, one of the brothers called the clinic stating he had developed an acute diffuse skin rash, described as maculopapular and blistering. He texted a picture of the rash. Sure enough, his twin brother developed the same rash at the same time.
We stopped methimazole and started propylthiouracil for both brothers, which was well tolerated with the rash improving. Methimazole-induced skin reactions are rare to start with — we have rarely seen that in my large and busy thyroid clinics, in different geographic locations, over the last 3 decades — so to occur in two recent patients, these twin brothers, at the same time seemed incredible.
Also, a few days ago, I saw a patient in the clinic. She is older than 30 years with a recent first pregnancy at about 8 weeks’ gestation. She and her husband had been trying to conceive without success, so they used to in-vitro fertilization. She wished to be seen on an urgent basis because a recent thyroid lab suggested that her dose of levothyroxine is too high. She was concerned because this is a precious pregnancy having occurred via IVF and at the same time high risk overall.
What makes it even more precious and more high risk is that she is carrying twins.
The usual scenario is the occurrence of multiple twins (two or more and certainly non-identical, or fraternal). This results from the transfer of more than one embryo during the IVF procedure.
So, I said: “Of course fraternal, non-identical, twins.”
She said, “No, identical.”
I asked, “What makes you so sure?”
She said, “They only transferred one single embryo, and it has split in two after implantation. They are identical twin girls!”
Now, how rare is this?
I have not searched the twins literature to check for the effects of IVF on the occurrence of identical twins, but I thought this was another intriguing story.