Di’George’s Syndrome Demystified

It’s been known for some time that the syndrome is associated with defects in chromosome 22. Large deletions in the chromosome, which remove approximately 3 million base pairs of DNA, take out a number of genes. These genes include a gene called Tbx1, implicated in mouse studies as a key gene in Di’George’s syndrome. In the January 21 online edition of Nature Medicine, the investigators report that they have honed in on a separate gene that appears to affect the severity of this disorder. Mice lacking this gene, VEGF, had birth defects resembling those found in Di’George’s patients. In addition, VEGF appeared to affect the amount of Tbx1 produced in mice.

The authors next took their experiments into zebrafish, a model of vertebrate development. In zebrafish with a deletion in chromosome 22, mutations in VEGF increased the severity of heart defects. What does all this mean for people? The definitive answer awaits further experiments. But the authors present initial evidence that mutations in VEGF are associated with an increased risk for cardiovascular birth defects in individuals with the characteristic deletion in chromosome 22.

Author contact:
Peter Carmeliet
Center for Transgene Technology & Gene Therapy
Katholieke Universiteit Leuven
Belgium
Tel: +32 1634 5772
E-mail: peter.carmeliet@med.kuleuven.ac.be

(C) Nature Medicine press release.

Message posted by: Trevor M. D'Souza