Congenital Disorders of Glycosylation (CDG) is a growing group of diseases among 8000 known rare diseases. Researchers and treatment developers on Rare Diseases like CDG are often challenged by multiple difficulties: lack of scientific knowledge about the disease, small patient populations, fragmented research, lack of biomarkers, and so forth.

Last January Bobby Ng and colleagues (2) showed that a novel compound called tetrasaccharide was a biomarker for either detecting or confirming a diagnosis of ALG1-CDG. “The benefit of this novel tetrasaccharide is that it is highly abundant in patients with ALG1-CDG. So when we find an unsolved type I CDG with this tetrasaccharide, we now know to go directly for ALG1”, refers study co-author Bobby Ng Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California.

Now, researchers documented 39 previously unreported cases of ALG1-CDG from 32 families.  Previous to this study, only 18 patients from 14 families have been reported to have ALG1-CDG. From 39 affected individuals enrolled into this study, all 27 had this tetrasaccharide present on either serum or fibroblast glycoproteins. This shows the added value of biomarkers to speed up research by understanding the pathophysiological mechanisms of diseases. In addition, biomarkers may offer an invaluable tool for monitoring disease progression, prognosis and response to drug treatment.

In addition, the current study augments knowledge about new mutations and robustness of the clinical picture of this subtype of CDG. “Early in this study it became clear that ALG1-CDG was more common than people had originally thought. So we reached out to collaborators to see if they too had come across additional cases and sure enough they had. Because of this international collaboration we are able to report on all 39 cases in one report, which can be more impactful than several single case studies. ”, says Bobby.

Thanks to this international effort, ALG1-CDG is now ranked as the third most common CDG type behind PMM2-CDG (CDG-Ia according to previous nomenclature) and ALG6-CDG (also known as congenital disorder of glycosylation type Ic).
Undoubtedly, this international research cooperation showed two main benefits for ALG1-CDG patients: acceleration of knowledge and improvement of diagnosis and care. This work is complemented by worldwide patient organizations efforts.

Keywords: ALG1-CDG, Biomarker, congenital disorders of glycosylation (CDG).

Information for families:

• Join the international families Facebook support group HERE
• Read CDG patient –friendly resources HERE
• Find your National CDG patient group/representative HERE
• About our Online Public Petition directed to World Health Organization (WHO) to declare 16th May as the annual World Congenital Disorders of Glycosylation (CDG) Awareness Day HERE

 
Literature used to prepare the news:
To request an article, please write to publicationscdg@gmail.com

1. Ng BG et al. ALG1-CDG: Clinical and Molecular Characterization of 39 Unreported Patients. Hum Mutat. 2016 Mar 2. [Epub ahead of print]
2. Bengtson P, Ng BG, Jaeken J, Matthijs G, Freeze HH, Eklund EA. Serum transferrin carrying the xeno-tetrasaccharide NeuAc-Gal-GlcNAc2 is a biomarker of ALG1-CDG. J Inherit Metab Dis. 2016 Jan;39 (1):107-14.
   
3. Clinical utility gene card for: ALG1 defective congenital disorder of glycosylation is available HERE

 
Relevant EU project focused on accelerating knowledge on Rare Diseases:

• ORPHANET: www.orpha.net
• EPIRARE (European Platform for Rare Disease Registries): www.epirare.eu
• RD-Connect: www.rd-connect.eu
• E-RARE 2 (ERA-Net for Research Programmes on Rare Diseases): www.e-rare.eu
• IRDiRC (International Rare Diseases Research Consortium): www.irdirc.org
• About the benefits from international cooperation HERE

Source of image:
Image courtesy of Stuart Miles at FreeDigitalPhotos.net

The Undiagnosed Diseases Network, funded through NIH Common Fund, is designed to accelerate discovery and innovation in the way we diagnose and treat patients with previously undiagnosed diseases. Please visit their website at http://www.genome.gov/27550959
For more information, a recent article was published: "Study offers hope for patients with rare diseases". Read more at http://www.wral.com/study-offers-hope-for-patients-with-rare-diseases/15469131/

Currently, in Spain there is a group working on chaperones for PMM2-CDG. Resource that can help to understand what are pharmacological chaperones and examples in which pathologies can be targeted with this therapeutic approach: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776907/

Newborn screening  and importance of patient registries are discussed in the following article: http://medicalxpress.com/news/2016-03-newborn-screenings-rare-diseases.html

Part of research done on rare diseases, is supported by families initiatives. Here, you can read a nice idea coming from kids that embraced the idea to support research! "  Right now, only 5 percent of rare disorders have an FDA approved treatment." said Robyn Nebrich-Duda, assistant director of development for the TGen Foundation. Initiatives like this one can make a difference in families lives! Read more at http://www.bizjournals.com/phoenix/blog/health-care-daily/2016/03/kid-philanthropists-raise-money-for-rare-disease.html