Fetal Procedure Prevents Rare Condition That Leaves Kids Unable to Sweat

Treated twins Maarten & Linus, and older brother Joshua
Treated twins Maarten and Linus, and older brother Joshua

WEDNESDAY, April 25, 2018 (HealthDay News) -- Doctors say they've found a way to head off a rare birth defect that causes babies to be born without functioning sweat glands.

By introducing a specific protein into the womb, researchers prevented the defect from taking hold in three children.

This is the first and only therapy shown to prevent the birth defect, said lead researcher Dr. Holm Schneider. He is a professor of pediatrics and head of the Center for Ectodermal Dysplasias at University Hospital Erlangen in Germany.

"If our findings can be confirmed in a planned clinical trial with a larger group of patients, this treatment may indeed become the new standard of care," Schneider said.

The condition, X-linked hypohidrotic ectodermal dysplasia (XLHED), occurs due to a genetic-driven deficiency of a key developmental protein called ectodysplasin A (EDA), the study authors said in background notes.

EDA plays an important role in the development of skin tissues and sweat glands in humans. Without its presence in the womb, sweat glands can form abnormally and be irreversibly impaired from birth onward.

Between one in 10,000 to one in 50,000 newborns have this birth defect, said Marja Mikkola, director of research at the University of Helsinki's Institute of Biotechnology in Finland. It runs in families due to a mutation of the gene responsible for EDA production.

Babies born with this disorder are in danger of overheating, and must be kept cool and well-hydrated. Estimates indicate that between 2 percent and 20 percent of babies with the condition die as a result of the birth defect, depending on how quickly they are diagnosed, said Mikkola, who wrote an editorial accompanying the study.

Previous mouse studies have shown that the birth defect might be headed off if a lab-created version of the EDA protein was introduced into the womb during gestation.

Schneider and his team decided to see if introducing EDA into the amniotic fluid surrounding a human fetus might have the same preventive effect.

Doctors can reliably predict XLHED in developing fetuses using sonograms as early as week 19 of pregnancy, Schneider said. The disorder also causes missing teeth, and doctors use the absence of fetal tooth germs to detect the presence of the birth defect.

The research team introduced their lab-grown EDA protein to a pair of twins in two doses, at weeks 26 and 31 of gestation. They also tried it out on a single fetus at week 26.

"This protein, however, works only within a certain time window, when the baby is still in the womb, so we have to administer it prenatally," Schneider said. "We learned from this trial that the replacement approach can only correct sweat gland development if the drug is provided at the right time. After birth, it simply becomes too late."

All three babies were born able to sweat normally, and no other illness related to XLHED had developed after more than a year following birth, the researchers reported.

According to Mikkola, "This is a remarkable achievement, as it shows that an inherited developmental disorder can be at least partially cured, and potentially a lifelong cure can be achieved by a short-term protein therapy."

The findings were published April 26 in the New England Journal of Medicine.

More information

The National Organization for Rare Disorders has more about hypohidrotic ectodermal dysplasia.

SOURCES: Holm Schneider, M.D., professor, pediatrics, and head, Center for Ectodermal Dysplasias, University Hospital Erlangen, Germany; Marja Mikkola, Ph.D., director of research, University of Helsinki's Institute of Biotechnology, Finland; April 26, 2018, New England Journal of Medicine
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