We got Giuliana’s genetic test results back in April but I haven’t been ready to post about them until now. Giuliana has been diagnosed with a rare mitochondrial disorder called Leigh Syndrome. Leigh Syndrome is a fatal neurodegenerative disorder that currently has no cure. Obviously, the diagnosis is devastating for us but we are focusing on enjoying the time we have with our beautiful daughter and giving her the best life possible.
Leigh Syndrome actually has about 200 known genetic causes and there are still many genetic causes that have not yet been discovered. In order to identify the genetic cause of Giuliana’s disease, she had a dual genome test done that examined a total of 199 genes that are known to cause Leigh Syndrome. Her doctor told us that there was a possibility that her genetic cause was something that had never been seen before in which case she would have to have more genetic testing done. We were relieved that her testing did reveal a genetic cause because we know that so many families never find the genetic cause of their child’s disease and not knowing is torture. Giuliana has a mutation in each copy of a gene called NDUFS8. There have only been 10 published cases of children with mutations in that specific gene although there probably have been more that were not published or were never diagnosed (since genetic testing for these types of disorders has only started within the last 5 years). The NDUFS8 gene itself codes for a protein that is part of an enzyme called Complex I. The Complex I enzyme is the first enzyme in a chain of 5 enzymes that the mitochondria use to produce energy, There are over 45 genes that are needed to produce Complex I (it’s one of the largest enzymes in the body) and Giuliana has a mutation in one of them but that’s enough to make her enzyme ineffective and to make her very sick.
Giuliana’s disease is a recessive disorder meaning that she inherited one mutation from me and one from her father making her father and I both carriers of the disease. Everyone is a carrier of several recessive disorders, however both parents have to be carriers of the same disorder for their child to have the disease. And even if both parents are carriers of the same disorder there is only a 25% chance that the child will inherit the disease. Unfortunately, her father and I both happen to be carriers of this very rare disorder and Giuliana fell in that 25% that inherit both mutations and have the disease. There are carrier tests that can be done to determine if someone is a carrier of a disease which her father and I did take. However, even the most comprehensive carrier screening only tests for the 200 most common genes to be carriers of and NDUFS8, Giuliana’s gene, is not one of them. Doctors know of at least 800 genes that can cause fatal recessive disorders but only the most common are screened for. Therefore, there was no way for us to have known that we were carriers before having Giuliana. The only way someone finds out that they are a carrier for something so rare is if they have an affected child. Because being a carrier in the NDUFS8 gene is so rare, doctors can’t tell us exactly how many people are carriers in that gene. They have given us estimates of anywhere between 1 in 100,000 to 1 in 1,000,000 people could be carriers. To put that in perspective about 1 in 30 Caucasians are carriers for cystic fibrosis which is also inherited in a recessive manner. The odds that we are both carriers of something so rare is hard to wrap our minds around but sadly it is our reality.
So for now we are focusing on our time with Giuliana. Despite her medical diagnosis Giuliana is an extremely happy little girl. Her smile and laughter brings joy to our hearts. She has taught us so much and brought us so much happiness. I love being her mom and am so happy to have her in my life. I treasure every moment I have with her. She will always be a blessing to me.
On September 27, 2014 Giuliana and her family will be participating in the Energy for Life Walk to help raise money to find a cure and treatment for Leigh Syndrome and other mitochondrial disorders. You can support Giuliana by donating directly to the United Mitochondrial Disease Foundation on Giuliana’s team page. Thank you in advance for your support.