Zebrafish may hold key to heart defects

  • 17/10/2015

The humble zebrafish may hold the key to understanding human heart defects, according to a new study.

Otago University researchers are seeking insight into Cornelia de Lange Syndrome, a developmental disorder which causes a range of physical and cognitive difficulties.

It affects about one in 10,000 babies worldwide, and to 70 percent of people with the disorder have congenital heart defects.

CdLS results from mutations in regulators of a group of linked proteins called cohesin, which are necessary for cell division.

Associate Professor Julia Horsfield said until now, reasons for heart defects in those with CdLS were poorly understood.

"Through our new study, we show that lowering levels of a particular cohesin protein called Rad21 in embryonic zebrafish produces similar types of heart defects to those found in people with CdLS," she said.

When researchers lowered levels of the Rad21 protein in zebrafish embryos, they found particular cells did not migrate to the heart, and the heart developed abnormally.

"Our findings suggest that heart development is exquisitely sensitive to the available amount of Rad21 and cohesin - it can be compromised even when there is sufficient cohesin present to support relatively normal growth," Professor Horsfield said.

"This also raises the possibility that mild mutations in cohesin genes may be the cause of some fraction of congenital heart defects in the general population."

The study was published in the journal Human Molecular Genetics.