By Ray Stern
By Ray Stern
By New Times
By Amy Silverman
By Stephen Lemons
By Stephen Lemons
By Monica Alonzo
By Chris Parker
The 21st chromosome happens to be very short, which means it contains less DNA material than other chromosomes. That might be why people with Down syndrome survive. In the case of trisomy 21, the name this kind of Down syndrome is called (trisomy means "third," in case you hadn't figured that out), every single cell in a person's body is different.
That's pretty mind-boggling. My husband likes to call Sophie our little science experiment, which he means in a much more endearing way than it sounds. When you think about it, it is pretty amazing that a person can have a totally different genetic makeup from normal humans and still function. Turns out that Down syndrome has been found in great apes, which means it's been around longer than the earliest humans. It wasn't until 1866 that a physician named Dr. Langdon Down officially described his collection of findings. (People often remark that it's funny that it's called Down syndrome, since people with it are often -- but not always -- very even-tempered and happy.) In 1959, the genetic cause of Down, the extra 21st chromosome, was first identified.
Basically, you can get Down syndrome in one of two ways. You can get it from a parent who is a carrier, or you can get it the more common way, in which a genetic mutation occurs spontaneously at the moment of conception. No one knows why that happens, but it's true that the older the mother is, the likelier the chance.
Sophie has the latter kind, which is called nondisjunction trisomy 21. That's not surprising, since I was older when I had her and we already had one typical child, which would presume it's unlikely that my husband or I are carriers.
Braxton, Tia and Tyler Huff were all born with nondisjunction trisomy 21. That's unusual, partly because Shawnie was only 25 when she started having kids, and partly because "nondisjunction" means nonrelated. Having one child with that form of Down syndrome increases your chances of having another to 1 in 100. Still pretty good odds, so the Huffs didn't think much of it when they got pregnant with Tia. Then an ultrasound revealed that she had a large hole in the lower chamber of her heart, a defect commonly associated with Down syndrome. The doctors increased her chances to 50/50. Shawnie says she was worried before Tia was born that she'd be disappointed if her daughter was born with Down, but that when the time came, she wasn't upset at all.
In fact, in a way, the Huffs were relieved.
One of the hardest things about losing Braxton, Shawnie and Kevin agree, was losing the community that had grown around him and around them. They were very active in Sharing Down Syndrome, and even as young and as ill as he was, Braxton had several therapy sessions a week. Suddenly, the doctors and therapists were gone, and things got awkward with the support group. That was horrible, because the Huffs don't have much family in town, and already they had grown apart from their old friends.
Shawnie has a friend on the East Coast. The two were so close, she planned to name Braxton after her friend's young son. When Shawnie called to tell her friend that Braxton had Down syndrome and was ill, Shawnie recalls that the friend assumed that the Huffs wouldn't name Braxton after her healthy child. (They still did.)
When Braxton died, Shawnie says her friend told her she was lucky.
"It's weird for us to talk to other people, because we don't fit into their world," Shawnie says. Now she and Kevin are more active than ever in Sharing Down Syndrome and also host a "good grief" group for parents who have lost a child with Down syndrome.
The Huffs are an anomaly even in the Down syndrome community, because they've had three children with it. Rick Wagner, their genetics counselor at the Arizona Institute for Genetics and Fetal Medicine in Chandler, has worked in the field since 1978 and has never seen a case of a family having three children in a row with Down. Wagner says he thinks that either Shawnie or Kevin has mosaicism, in which the cells mutate after conception. That means that only some of the body's cells are affected, rather than all of them. In this case, Wagner believes, either Shawnie's ovaries or Kevin's testes are affected. They've had blood tests, which reveal nothing; even a biopsy might not reveal the cells, since they're not present everywhere, Wagner adds.
In any case, the Huffs don't really want to know.
With Tia's heart fixed and Tyler so far having suffered nothing worse than a really bad case of croup, life in the Huff household is relatively normal -- as normal as life can be when you have to expect that your kids won't learn how to do anything (from drinking from a bottle to sitting up to saying "Mama") without great assistance.
Four mornings a week, state-paid therapists come to the house to work with both Tia and Tyler, and Shawnie is the ultra-efficient mom, balancing sleeping Tyler on her shoulder while helping to arrange an intricate obstacle course of musical toys and benches for Tia to use with the physical therapist.