Wednesday, February 29, 2012

Finally we have proof! Doctors often misinform parents about zygosity

Throughout my pregnancy, my OB and the ultrasound technician told us our boys were absolutely, positively, no-doubt-about-it fraternal. Yes, my doctor said, identicals can have separate placentas and sacs, but mine implanted too far apart to be identical.
Their placentas were on polar opposite sides of the uterus.
Identical twins implant more closely, he said.
He was wrong.
And he has company.
In a new study from University College London, researchers found that doctors wrongly told parents their identical twins were fraternal in 27.5 percent of the cases. Like my guys, those twins had their own sacs and placentas.
The study also found that 2 percent of parents were wrongly told their fraternal twins were identical because doctors did not realize their separate placentas had fused into one. Overall, 15 percent of twin parents were misinformed about zygosity.
I have long suspected the statistics involving identical twins are skewed.
This proves it.
So many parents find out long after birth that their twins are identical through DNA testing. That information is never reported to any statistic-gathering source. If this study hold true in the US, then statistics showing the odds of having identical twins is about 3 in 1,000 are way off.
It has become a game on online twin forums: Guess whether the twins are identical while the parents await results of DNA testing. In most every case where parents of di/di had trouble telling their twins apart, the results showed they were, indeed, monozygotic, or identical.
I have come across just as many parents of look-alike twins in real life and virtually who decline testing despite their gut feelings. Either they can't afford the $100 to $200 fee or they see slight differences between their twins and accept those as evidence their twins are fraternal.
We could have done that do that with our guys.
Matthew has a slighter build and a thinner face. Jonathan is much more muscular and has a rounded face -- a little more body fat in his cheeks. But that scenario is true of most identicals. One usually has a slightly different facial shape than the other.
In some of those cases, parents brushed off their identical suspicions because their hospitals "tested" the placentas and the results showed they were dizygotic, or fraternal.
Our own doctor fell for that until I pressed him for more information and he checked with the hospital.
It turns out hospitals check only whether placentas are fused. The hospital techs either definitively declare the zygosity according to the results or the pass the results on to doctors or midwives who were told in medical school that two placentas equals fraternal.
The doctors or midwives then pass that misinformation on to parents.
Remember this: hospitals DO NOT do DNA testing.
In the defense of OBs, midwives and ultrasound technician, zygosity is irrelevant in caring for pregnant women. What matters is only whether there is one placenta or two, and one sac or two. So they really don't need to know for medical purposes.
That doesn't, however, excuse the giving of misinformation.
In our case, a fellow soccer mom who was a neonatologist educated me.
She told me that identical twins implant separately when the split occurs immediately after conception -- within the first few days. Matthew and Jonathan probably became two far up in the fallopian tube, she said, allowing them to fall and implant independently, just like fraternal twins.
At the very least, our OB should have told us he didn't know.
He should have known that he didn't know.
All doctors, midwives and ultrasound technicians should know that they can't be certain with same-gender twins until after the babies are born. Though the information is medically irrelevant during pregnancy, there is no excuse for being misinformed about something so relevant to the field in general or for passing that information on to parents.

Wednesday, February 15, 2012

Identical twin loses brother to war

I cannot even begin to imagine losing any of my children (nor have I any desire to do so), and I have no recollection of a sibling I lost at too-early an age.
But even farther beyond my comprehension is the loss of an identical twin.
My heart aches for Osmany De Oca, whose identical twin brother, Lance Cpl. Osbrany Montes, was killed in Afghanistan Friday while serving his country as a member of the U.S. Marine Corps, according to the Bergen County Record.
Osbrany Montes was 20.
Yes, the twins and their older brother,  Sandro Moreta, knew they were risking their lives when they enlisted, but who honestly considers that reality when they sign up?
I have read about identical twins and loss and the permanent void it leaves within them. I have talked about such loss with a friend who lost one of her identical twin brothers at a young age, and the effect his death has had on her surviving brother.
I hope that is all I ever know of it.
I hope my children never know any of it.
My deepest condolences go out to the De Oca family along with my deepest gratitude for the service and sacrifices of their sons.

Thursday, February 2, 2012

Sick and sicker: immunity differences in identical twins

Jonathan and Matthew developed colds a while back.
Jonathan is on the mend now, racing the dog from the dining room through the kitchen, eating like a teenager and jumping from the sofa to the floor over and over and over again, ignoring my demands that he stop.
He's driving me crazy.
Matthew is curled up on another sofa, covered with a blanket and watching TV through half-opened eyes. It breaks my heart to watch him hold his ribs when hacking coughs overtake his body. I can't wait for the antibiotics to do their stuff.
He has walking pneumonia.
This medical inequity is nothing new.
A few weeks ago, Jonathan developed a fever that lasted for two days. Matthew caught the same virus, but his fever continued for seven days. A stomach bug that left Jonathan slightly dehydrated for a day as a baby left Matthew with bleeding ulcers and a month's prescription of Zantac.
When Jonathan develops an ear infection, Matthew often gets it in both.
My immediate reaction was to surmise that somehow, when the egg split, Matthew lost an immunity gene to Jonathan. It made sense. Matthew's always been sicker and he was born lighter, slighter, a bit more frail than his brother.
But I came to a different conclusion after doing a little research.
Recent studies are finding that epigenetics -- or the way in which genes express themselves in different environments -- is likely responsible for many differences that develop in identical twins, particularly when it comes to immunity.
Sometime after conception, either in the womb or outside it, one of the twins was likely exposed to a virus or bacteria that missed the other. In fighting off the intruder, he either gained any army (Jonathan), strengthening his physical fortress, or lost one (Matthew), weakening his defenses.
Their identical genes learned to express themselves in different ways when confronted by bacterial infections or viruses, resulting in permanently different immune systems.
Amanda Carpenter, a virology student, writes about an excellent example here. Identical twins born in 1983 were exposed to HIV, the virus that causes AIDS. Fifteen years later, one was relatively healthy and strong while the other was sickly and ill.
After studying blood samples from the pair, researchers concluded that environment, which led to a depressed immunity system in one twin, was likely to blame for their different reactions. Their shared DNA did not ensure a shared prognosis.
My hope for Matthew is that someday this will turn itself around -- that someday he'll be exposed to something that makes him stronger instead or weaker -- and that Jonathan's immunity will remain unchanged.
Who knows?
Maybe this is the one.
Maybe all that hacking and coughing that kept me up last night, worried that he will choke or stop breathing, is the just influence his genes needs.