What is Cobalamin C Deficiency?

In the first few weeks of Ryder's life, we spent hours upon hours researching his potential diagnosis, and even more hours hoping that somehow the newborn screening test had been wrong.

The metabolic doctor we first met with (and continue to see now) told us that it was most likely that Ryder had something called Cobalamin C Deficiency (also called: Methylmalonic acidemia with homocystinuria).  His diagnosis was based on two levels on his newborn screening that were extremely elevated. We had never even heard of either of these things but quickly learned a lot about them.   

• Methylmalonic acid: normal level is between 0 and 4.  Ryder's level at birth was 246. 

• Homocysteine: normal is less than 10.  Ryder's was 186.  

The main reason we had never heard of this condition is because there are only 300 people in the world affected by it.  Prior to 2006 (I believe…), methylmalonic acidemias (there are several sub-types) were not tested for on the newborn screening.  As a result of that, many children went undiagnosed until they had suffered a metabolic crisis which often resulted in permanent neurological damage and/or death.  (So obviously we are incredibly thankful for newborn screening!)

Without going into too much detail and boring science stuff, why Ryder has CblC:

• Ben and I are both (unaffected) carriers of a specific mutated gene.  Ryder received one defective copy of this gene from each of us, which caused him to be affected. (Ethan is unaffected, but has a 66% chance of being a carrier.  He will not be tested until he is 18 years old.)  
• Any future children we may have will have a 25% chance of being affected, 50% chance of being a carrier, and 25% of not carrying a copy of the gene.
• Essentially Ryder has a defect in this specific gene that causes his body to be unable to use vitamin B12 correctly (this is different than a traditional B12 deficiency).  

Below is a brief description from some of the information we were given by the metabolic doctor about how this condition "works":

• In order for the body to use protein from the food we eat, it is broken down into smaller parts called amino acids. Special enzymes then make changes to the amino acids so the body can use them. 
• Cobalamin C Deficiency occurs when one of these special enzymes is either missing or not working properly. 
• The job of these enzymes is to change vitamin B12 (also called cobalamin) into a form that the body can use. 
• Vitamin B12 is essential to your health and helps with neurological function, red blood cell production, and helps in DNA synthesis.  
• When the body is not able to use vitamin B12 correctly, it causes homocystine, methylmalonic acid and other harmful substances to build up in the blood. 
• Ryder will need a protein-restricted diet (no meat, eggs, dairy, etc.) to decrease the amount of methylmalonic acid and homocysteine that build up in his body.

For all of you visual learners, here is a diagram:

The not-so-nice potential symptoms of CblC include:

• poor appetite
• poor growth
• extreme sleepiness or lack of energy
• low muscle tone (floppy muscles and joints)
• seizures
• small head and brain size, called microcephaly
• water on the brain, called hydrocephalus
• other brain abnormalities
• delays in learning
• vision problems
• heart problems
• kidney problems
• skin rashes

This condition cannot be "cured" (i.e. Ryder will be affected by this condition for his entire life) and even with medication and treatment, the prognosis is still unknown.  We have only seen a few of these symptoms at this point, which is great, but I will get into that in another post.  
By far, it is the "unknowns" and the additional problems with Ryder's health that we may face in the future that are the most frightening, but we are learning to take life as it comes, and be thankful for all that we have.

We continue to be positive and optimistic about the future.  Ryder was diagnosed incredibly early on in his life compared to other cases we have read about in the scientific journals and articles.  We are hopeful that early detection will lead to a more positive outcome and that new treatments will be developed in the near future.

Pure and complete love for these two!
Photo credit: www.linsdaypalmer.ca

I know there is a reason we were chosen to be Ryder's parents
and a reason he was given to us.    

I truly believe that we are never given more than we can handle in life
(even though I sometimes have to remind myself of this more than once each day!)

For more information go to: http://www.newbornscreening.info/Parents/organicaciddisorders/MMA_HCU.html