Hudson Freeze, Ph.D.

Glycosylation: An Essential Function

The entire cell surface is coated with sugars in complex chains that promote (or sometimes interfere) with cell-to-cell communication. These sugar chains are first attached to proteins deep inside the cell where they help them get into shape for their jobs. As the proteins percolate toward to cell surface and beyond, the sugar chains are sculpted for specific needs. This entire process, called glycosylation, recruits a force of more than 500 genes for this job. The Freeze lab works on several facets of glycosylation, all of them with an eye toward therapeutic applications for diseases that impair the functions of these critical genes. 

Human Glycosylation Disorders

We focus is on a group of metabolic diseases called Congenital Disorders of Glycosylation (CDG). Today we know of defects in over 140 genes, well over double those known only 10 years ago. Patients with these diseases have highly variable mental and motor developmental delay, seizures, failure to grow, hypoglycemia (low blood sugar), clotting and digestion abnormalities and skeletal abnormalities to name just a few. These are rare disorders having a few thousand known patients worldwide, but it is likely that many remain undiagnosed, especially in developing countries.

Growing awareness

Physicians are becoming more aware of glycosylation disorders in general, and basic scientists continue to discover sugar chains at the helm of many basic metabolic processes. Defective glycosylation is also known to cause 15 types of muscular dystrophy.

Working with CDG kids

Rocket: We helped diagnose this young man over 10 years ago, and although he tragically passed away, his gentle face still reminds us of who we work for.  

Brianna: Sometimes our work leads to brighter outcomes as in the case of Brianna who we met over 20 years ago and treated with a simple therapy.  

Our collaborations

The Freeze lab not only identifies new glycosylation disorders, but also tries to understand how these defects cause the disease manifestations. Defects occur in genes that activate and transport sugars, assemble them into glycans and remodel them. Some also traffic and distribute the glycosylation machinery within cells. Ongoing collaborations with academic physicians provide a steady flow of new patients for analysis. Since very few laboratories in the United States work on CDG, we are developing new molecular diagnostic methods to handle the increasing number of patients. Increased awareness of CDG in the medical community generated expanded government funding that allies us with 10 medical centers in the US seeking additional patients to study their natural history, develop biomarkers and test emerging therapies. Those avenues along with the help of generous philanthropic support, enables us to extend efforts to supplement the depleted glycosylation pathways in patients.