What is Congenital Disorder of Glycosylation? (CDG)

Congenital Disorders of Glycosylation (CDG), formerly called carbohydrate-deficient glycoprotein syndrome, are a group of inherited disorders that affect a process called glycosylation.


Glycosylation is a process by which all human cells build long sugar chains that are attached to proteins. Together the proteins and their attached sugars are called glycoproteins. Glycoproteins, have many very important functions in the human body and are required for the normal growth and function of all tissues and organs. The process or pathway which makes this glycosylation takes at least 100 steps, and specialized proteins called enzymes trigger each step. Hundreds of enzymes are used in making the sugar chains and adding them to thousands of proteins. Sometimes coordinated groups of enzymes work in a specific order to add some sugars, or cleave others from the maturing chain. In individuals born with CDG, one of the many glycosylation enzymes in the pathway malfunctions. However, the impact on the body structures and functions differs depending upon the altered enzyme. CDG is caused by a genetically inherited change or malfunction of one of these enzymes. If one of these enzymes malfunction then the cells in the body of a child or adult cannot glycosylate correctly. This incorrect glycosylation is the underlying basis of the important medical issues in individuals with CDG.

Types of CDG

The CDG’s were initially divided into groups I and II based on the location in the biochemical pathway which the defect occurs. Defective genes are lettered in chronological order of their discovery. CDG research is quickly evolving, types are now recognized to include Ia through IL and IIa through IIf. Many are so new that only 1 or 2 patients are known. Scientists are working now to identify other types of CDG.

My ladybug is one of 3 little ones that have CDG SLC35A2 and is thus far the only girl in the world with this type of CDG. However, I’m truly hoping now that the researchers have discovered this brand new type of CDG more children will be diagnosed at an earlier stage.

Signs and Symptoms

The symptoms and severity of CDG vary from child to child. Some of the symptoms become more prominent at different ages. Most types of CDG are associated with minor differences in facial and body features, neurological problems, slow growth, clotting problems, liver and/or intestinal problems and the most heart breaking of all is that many children with CDG succumb to the disorder as there is no treatment or cure.

Some of the children have significant medical problems during infancy. Physicians should suspect CDG in children who present with the following signs and symptoms:

• hypotonia (low muscle tone)

• failure to thrive (slow growth)

• developmental delay

• hepatopathy (liver disease)

• coagulopathy (bleeding tendancies)

• esotropia (crossed eyes)

• seizures

• cerebellar hypoplasia (changes in the brain that can be seen on developmental delay)

At a later age, adolescence or adulthood, affected individuals may have these additional clinical features:

• ataxia (poor balance)

• dysarthria (slurred speech)

• absent puberty in females

• retinitis pigmentosa (pigment in the retina of the eye)

• progressive scoliosis (curvature of the spine)

• joint contractures


There is no specific medicine to treat CDG, except for CDG-Ib and some CDG-IIc patients. Current treatment for CDG patients is supportive therapy and treatment of symptoms and sequelae. The effective therapy for CDG-Ib is oral mannose. CDG-Ib presents with protein-losing enteropathy, coagulopathy and liver disease without neurological involvement. These patients have significant gastrointestinal problems, but are neurologically and intellectually normal. Fucose supplements have been used to treat patients with CDG-IIc who have a defective GDP- Fucose transporter. Infections cease and health improves. Unfortunately, fucose does not improve or reverse the developmental delay.

24 Responses to “CDG”


  1. What Not To Say « Little Ladybug Hugs - January 31, 2011

    […] been a stinky tushy to change in 5 days, and she has started to spit up again. With the CDG, her “short gut” from the bowel resection, and the past GI bleed,  it’s so hard […]

  2. CDG Family « Little Ladybug Hugs - February 13, 2011

    […] Today was a little different though – I had 30 emails from the CDG Family Network forum in my inbox all sent within 3 hours of each other. Once again my heart sank, this many emails usually means one thing. A beautiful 2-year-old boy passed away and is now a sweet little angel. It’s heartbreaking. Not only did this little boy leave the world far too early, he left it because of CDG. […]

  3. Health Care Hindrances « Little Ladybug Hugs - February 25, 2011

    […] heal my baby girl, sadly nothing can, but it may give us a peek through the window of her future. CDG is so uncertain it can be fatal to one child and then spare the […]

  4. Rare Disease Day « Little Ladybug Hugs - March 1, 2011

    […] early October 2010 when my daughter was diagnosed with Congenital Disorders of Glycosylation (CDG) that changed. February 28th marks Rare Disease Day. A day to bring awareness to all rare diseases […]

  5. Sweet Little Angels « Little Ladybug Hugs - March 13, 2011

    […] me this is exactly what happens when I learn that a child with CDG has become a sweet little […]

  6. Deja Vu « Little Ladybug Hugs - March 25, 2011

    […] before, it’s a day-to-day process and because of the CDG that process may take a wee bit longer but eventually we will get […]

  7. A First For Everything « Little Ladybug Hugs - March 28, 2011

    […] because I want people to know about my daughter, and the fact that she has a rare disorder known as Congenital Disorders of Glycosylation – CDG. I want the attention in order to bring awareness to Canadians and the world that Canada is the […]

  8. Swing of Things « Little Ladybug Hugs - April 13, 2011

    […] those who aren’t familiar with our sweet ladybug’s journey thus far it may seem a bit odd that I’m beyond thrilled for this milestone. You see, up […]

  9. Lights, Camera, Action! « Little Ladybug Hugs - May 23, 2011

    […] – what an incredible opportunity to share our story and most importantly shed some light on CDG. Then I started to get a little apprehensive. For the most part I am very open when it comes to […]

  10. No Such Thing as a Silly Question « Little Ladybug Hugs - June 30, 2011

    […] importantly that is how others learn about life with a child who has special needs, CDG, and how amazing our ladybug […]

  11. Perfect To Me « Little Ladybug Hugs - July 7, 2011

    […] the odd ‘Mum Mum’ (rice rusks cookie) and otherwise being tube fed. To me my ladybug is perfect CDG and all. Albeit, I have may have the odd breakdowns about her health issues now and then after all […]

  12. Going Global « Little Ladybug Hugs - July 31, 2011

    […] would be a chance for geneticists from all over the world to learn about and discuss CDG.  I didn’t even hesitate to say yes – after all this is exactly the type […]

  13. CDG Awareness « Little Ladybug Hugs - August 14, 2011

    […] me the coloured hands are symbolic of the many different characteristics and faces of CDG. The hands joining into the shape of a heart represents the unity of all CDG families coming […]

  14. Happy 1 Year Little Ladybug Hugs! « Little Ladybug Hugs - August 23, 2011

    […] was found and in turn a portion of her ulcer covered bowel was removed, a confirmed diagnosis of CDG type 2x was given, we’ve become a part of a wonderful and supportive new family, and ladybug […]

  15. 2 Years or 24 Months? « Little Ladybug Hugs - August 31, 2011

    […] For those that do pick up on her age I either get the look of puzzlement or they inquire as to why she is so little. As I’ve said time and time again I love when people ask questions. It gives me the opportunity to tell them about CDG. […]

  16. True Strength « Little Ladybug Hugs - February 3, 2012

    […] when I just keep saying it isn’t fair! It just isn’t fair! There is no treatment for CDG, there is no cure for CDG it just isn’t […]

  17. Feeding Tube Awareness Week « Little Ladybug Hugs - February 9, 2013

    […] before the CDG diagnosis came to light, Ladybug was diagnosed with failure to thrive. Failure to thrive (FTT) is a […]

  18. Purple Day! | Little Ladybug Hugs - March 26, 2013

    […] to begin.  One of the characteristics of many children with Congenital Disorders of Glycosylation CDG is epilepsy. When most think of seizures they tend to think of what is known as a Tonic Clonic or […]

  19. 1 in 7 Billion | Little Ladybug Hugs - May 23, 2013

    […] we received an email that essentially changed our lives.  When Ladybug was first diagnosed with CDG we pleaded with the Ministry of Health (Canadian Government) to cover a genetic test for her. […]

  20. Discovering CDG SLC35A2: A Parents Perspective | Little Ladybug Hugs - July 5, 2013

    […] more to it that I wasn’t ready to talk about. From the initial diagnosis we were told that CDG was a genetic disorder and that Ladybugs father and myself were carriers. Makes sense! With CDG […]

  21. 3 Years and Thriving! | Little Ladybug Hugs - August 23, 2013

    […] bolus feeds with a 60CC syringe through her NG tube and we were months away from getting her CDG […]

  22. Look Mommy, I Did It! | Little Ladybug Hugs - October 1, 2013

    […] instinct was not to remove it from her hand but to grab the camera. There are so many unknowns with CDG that I will not pass up any opportunity to capture a single moment in Ladybugs […]

  23. Fighting an uphill battle. | Little Ladybug Hugs - April 21, 2014

    […] This past December a brave little man from our CDG family was admitted to the hospital. For our kids this is a common occurrence, especially around the cold and flu season. This little superhero was otherwise stable in the weeks previous to this admission. He was probably in contact with someone who had a bad cold or some other type of virus that his body couldn’t fight off. Whatever disease a medically fragile child might be fighting chances are their immune systems are extremely low to non-existent. This is the case with my little Ladybug and other children with Congenital Disorders of Glycosylation. […]

  24. In Honour of Rare Disease Day – Help Me Get CDG Recognized as an Official Day. | Little Ladybug Hugs - February 29, 2016

    […] my daughter was first diagnosed with Congenital Disorders of Glycosylation, there wasn’t a lot of information or even support for families like myself.  At the the […]

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