NEW ORLEANS -- Last fall, researchers at UC San Francisco announced that they had identified an elusive gene critical for vitamin D metabolism. Now they have identified mutations in that gene, paving the way for genetic diagnosis of a hereditary form of childhood rickets.
Further analysis of the gene, say the researchers, could lead to an understanding of other vitamin D deficiency disorders, as well. The finding, presented at the Pediatric Academic Societies' annual meeting here today (May 2), will even allow for prenatal diagnosis of the metabolic disorder, known as vitamin D-dependent rickets. It will also allow for genetic testing of adults to determine if they carry a latent form of the genetic mutation that could be passed on to their offspring.
"Identifying the genetic mutations that cause hereditary vitamin D-dependent rickets is likely to increase the number of diagnoses made of the condition, which will allow for earlier treatment," said Walter Miller, MD, UCSF professor of pediatrics and senior author of the study.
"And being able to genetically diagnose adults as carriers of the mutated gene," he said, "will enable us to alert parents to the possibility that their future offspring may carry the disease. This way the children can be evaluated for the disorder and, if necessary, begin treatment early in life."
Children with hereditary vitamin D-dependent rickets cannot metabolize vitamin D to its active hormonal form and, as a result, have difficulty growing healthy bone. They develop poorly, have abnormal teeth and develop rickets, or deformed bones. The condition is corrected by treatment with a synthetic form of the active vitamin D hormone.
The researchers carried out their study by examining samples of DNA collected
from 20 patients in 18 different families from around the world. They
identified nine mutations in the gene, known as P4501 alpha, and determined that
these mutations give rise to truncated enzymes that are un
Contact: Jennifer O'Brien
University of California - San Francisco