St. Louis, MO (AHN) An international team of researchers has partially unraveled the genetic details of a mysterious disorder that formerly caused seizures and death in infant boys within one month of birth.

Researchers discovered a rare change in the DNA of two eastern Missouri families with a history of a condition called X-linked recessive idiopathic hypoparathyroidism (XLHPT): a portion of the X chromosome, a human sex chromosome, has been removed and replaced by a copy of a much larger section of genetic material from chromosome 2. Alterations of such large regions of genetic code that stably pass from one generation to the next are generally rare and have never before been observed in the human X chromosome.

The study was led by scientists at Oxford University in England and included researchers from Washington University School of Medicine and Shriners Hospital for Children in St. Louis.

In the long term, the disorder's links to blood calcium levels and parathyroid hormone secretion may someday help scientists seeking to develop new treatments for osteoporosis. For now, though, the findings almost bring to a close a decades-long investigation into the disorder that has plagued two Missouri families for generations.