Did Scientists Find a New Congenital Disorder of Glycosylation?

Scientists discover new congenital disorder of glycosylation.

shafere1 [at] chop.edu (By Emily Shafer)

The findings:

Researchers uncovered a new genetic syndrome in the family of congenital disorders of glycosylation. The new disorder is caused by pathogenic variants in the EDEM3 gene, which is known to play a role in glycosylation — a process that takes the body’s proteins and modifies them by adding “sugar building blocks” to make them functional.

Why it matters:

Congenital disorders of glycosylation are a group of disorders that typically cause developmental delays and other challenges, such as speech impairments, abnormal facial features, and feeding difficulties. The symptoms vary in severity from mild to severe. In this study, the researchers identified seven different families with a total of 12 affected children.

Who conducted the study:

The study was a collaboration between institutions worldwide. Andrew Edmondson, MD, PhD, attending physician in the Division of Human Genetics at CHOP, was co-first author. Elaine Zackai, MD, director of Clinical Genetics at CHOP, was also involved in the study.

How they did it:

The researchers followed patients who presented with abnormal facial features, developmental delay, and/or intellectual disability and speech delay that were indicative of an unknown genetic disorder. The researchers conducted whole exome sequencing on patients’ blood and identified a variant on the EDEM3 gene in the affected individuals. They verified the findings in a mouse model.

Quick thoughts:

“The main message here is that we’ve identified a new genetic cause of congenital disorders of glycosylation,” Dr. Edmondson said. “There are more than 700 genes involved in the process of glycosylation, and as science advances, new genes and mutations are regularly being identified as playing a role in these disorders. There are certainly more undiagnosed disorders out there are caused by defects in glycosylation.”

Where the study was published:

The study appeared in American Journal of Human Genetics.