Thyroid disease a possible risk factor for craniosynostosis.(News)

TUCSON, ARIZ. -- Maternal thyroid disease or its treatment may increase the risk of craniosynostosis in offspring by nearly threefold, preliminary results from an ongoing study suggest.

The finding is important because thyroid disease is the second most common endocrinopathy, after diabetes, in women of reproductive age, Dr. Sonja A. Rasmussen said at the annual meeting of the Teratology Society.

"Several case reports in the medical literature have linked craniosynostosis to postnatal hyperthyroidism and with maternal Graves' disease during pregnancy," said Dr. Rasmussen of the division of birth defects at the Centers for Disease Control and Prevention, Atlanta.

"Congenital hypothyroidism is associated with delayed closure of the fontanelles. In addition, thyroid hormone is known to play a key role in normal bone metabolism, acting on both osteoblasts and osteoclasts.

"This information suggests that excess thyroid hormone might lead to premature cranial suture fusion," she said.

To examine the relationship between maternal thyroid disease and craniosynostosis, Dr. Rasmussen and her associates used data from the National Birth Defects Prevention Study, an ongoing population-based case-control study of major birth defects.

The data included maternal interviews and clinical information on 4,555 infants who were born between Oct. 1, 1997, and Dec. 31, 2002, in Arkansas, California, Georgia, Iowa, Massachusetts, New Jersey, New York, and Texas.