OLMITO — Two days before Thanksgiving, Annie Alvarez received devastating news. She was told that her unborn baby — whose arrival she was eagerly anticipating — had a congenital defect that could leave the infant paralyzed.

At first, the doctors thought the baby would have spina bifida, an incomplete closure of the spinal column. Later, Alvarez learned that the defect was gastroschisis, in which the baby’s intestines protrude from the body. Her baby, Alvarez was told, would have to undergo surgery shortly after birth to put the organs back in her tiny abdomen.

Immediately after Gabriela was born, paramedics whisked her to a Corpus Christi hospital for surgery. Alvarez couldn’t see her for days.

“For two weeks, we couldn’t carry her or hold her,” Alvarez said. “I was so depressed that I couldn’t be with her.”

Gabriela, now 2 months old, has recovered from surgery and is home with her parents in Olmito. Her digestive organs are delicate — doctors told Alvarez that if Gabriela ever plays sports she’ll have to wear a special guard — but she should lead a mostly normal life, her parents said.

“It was very hard to see our little girl like that,” said Jesus Alvarez, cradling the baby in his arms. “Now she’s home, and it’s the best.”

A surprising number of Rio Grande Valley families face the heartache of finding out a child has a debilitating birth defect. According to figures from the Texas Department of State Health Services, the Valley has some of the highest rates in Texas of common birth defects like heart conditions, Down syndrome and gastroschisis. In addition, doctors say they treat many Valley children with unusual birth defects, like genetic malformations that might only run in one family.

“We see a lot of Valley children with malformation syndromes … genetic abnormalities that are new and don’t even have a name,” said Dr. Raymond Lewandowski, a geneticist at Driscoll Children’s Hospital in Corpus Christi. About half of the patients Lewandowski sees are from the Valley, he said.

“We have large numbers of patients referred to us that don’t have a match (for that defect) anywhere else in the world,” he said.

Researchers have examined the issue from all angles, trying to understand why families along the Texas-Mexico border seem more susceptible to defects with and without names. State epidemiologists suspect the trend might not be as drastic as it seems, but that doesn’t mean something isn’t happening on the border, they say.

“We’re not sure — it could be a higher prevalence, and there could be other factors involved,” said Peter Langlois, senior epidemiologist for the Department of State Health Services.

Keeping a close eye

The numbers seem clear. The prevalence of ventricular septal defect — a defect of one of the chambers of the heart — was 82.5 per 10,000 births in Hidalgo County in 2003, compared to only 45 per 10,000 in the state. In Cameron County, the prevalence was 91.5 per 10,000. The figures from 2003 are the latest available. For spina bifida, Hidalgo County’s prevalence was 5 per 10,000, compared to the state’s 3.5. Cameron County’s prevalence was 4.7 per 10,000.

More ambiguity exists in the numbers than one might think, however. Langlois said he has “reason to believe” that more thorough recording and diagnosis of birth defects is taking place in South Texas, particularly in Corpus Christi, and that this vigilance might be skewing birth-defects rates when compared with the rest of Texas.

“Doctors in South Texas … seem to refer patients for minor heart defects more often (for testing), for example,” he said.

With each referral, that case is added to the state’s birth-defects registry.

In other parts of Texas, similar cases might never be reported, Langlois said.

South Texas doctors have reason to be vigilant after a rash of neural-tube defects cases occurred in the Valley in the early 1990s. Neural-tube defects are malformations of the brain and spinal cord.

As a result of this cluster of cases, the state launched its birth-defects registry and implemented aggressive awareness campaigns and education about folic acid, which our bodies use to make new cells. If a woman has enough folic acid in her body before she is pregnant, it can help prevent major birth defects of her baby’s brain and spine, according to the national Centers for Disease Control and Prevention.

To be sure, the Valley’s population is at greater risk for birth defects, researchers say. Studies suggest that certain birth defects are much more prevalent among Hispanic families, and other research suggests that Valley women’s folic-acid intake is inadequate, making them susceptible to giving birth to babies with defects.

To find out just how skewed the region’s birth-defects numbers might be, state epidemiologists performed an analysis of the most severe defects in Corpus Christi’s Nueces County.

In general, severe defects were 17 percent more prevalent in Nueces County than the state average, the epidemiologists found.

The state hasn’t conducted a similar analysis in the Valley yet, but a similar trend is possible, Langlois said.

Possible causes

Researchers have spent years trying to solve the mystery of why several babies were born with anencephaly — with a portion of their brains missing — in Brownsville in 1991. They have studied every imaginable possibility, from air pollution to pesticide exposure to nutritional deficiencies. A group of researchers last year concluded that fungus-contaminated corn tortillas might have been the culprit, and also found that women who consumed a high number of corn tortillas were more likely to have children with birth defects.

The bigger question, of why high birth-defects rates seem to persist on the border, remains unanswered, however.

One problem is that researchers don’t really know what causes most birth defects, making speculation difficult, experts say.

“We’re trying to engage in research when we don’t even know what causes two-thirds of birth defects,” said Langlois.

According to the March of Dimes, a national agency that seeks to improve babies’ health, about 70 percent of birth-defects cases have an unknown cause.

Investigators have considered stress, obesity, diabetes and exposure to hazardous waste or heavy metals as possible causes of neural-tube defects along the border, finding some associations. But reasons for a higher prevalence of other birth defects along the border are tougher to ascertain.

“It’s a long process of unraveling,” said Lewandowski of Driscoll Children’s Hospital.

Researchers would need to perform DNA sequencing to single out genetic factors involved, as well as researching environmental factors, he said.

Lewandowski isn’t sure why he sees so many Valley families with birth defects that seem purely genetic. If the defect is contained in just one family, the defect has a “clear genetic component,” he said.

Because the Valley population is fairly stable, with generations of families living in the region, it might be possible that distant cousins are getting married and having children without realizing they’re related, Lewandowski said. Children of relatives, even distant ones, are more likely to have genetic abnormalities, he said.

One point on which experts agree is the importance of folic acid in the equation. Studies have shown that few women on the border take folic acid or get enough folate in their diets, making neural-tube defects more likely.

The U.S. Department of Agriculture recommends that women of childbearing age consume 400 micrograms of folic acid a day, either through supplements or by eating fortified cereals, leafy vegetables, beef liver, spinach or black beans.

Because of educational programs in the region, women on the border are more likely to know about folic acid, but they still tend not to take in enough of it, according to Amy Case of the Birth Defects Epidemiologist and Surveillance Branch of DSHS.

Taking folic acid, obtaining prenatal care and avoiding drugs and alcohol are a few ways to prevent many types of birth defects, the March of Dimes says.

Researchers still are trying to get to the heart of why birth defects occur in the Valley and nationwide, Langlois said. A large-scale study funded by the CDC is just now yielding some possible answers.

“The purpose is to try and find preventable causes of these birth defects,” Langlois said.

Melissa McEver covers health and environment issues for Valley Freedom Newspapers. She is based in Harlingen and you can reach her at (956) 430-6252. For this and more local stories, visit www.themonitor.com