Q: What is NKH?
A: Nonketotic hyperglycinemia, NKH for short, is a rare genetic disorder that affects 1 child in every 60,000 born. Children with this condition have a problem breaking down the amino acid glycine. This is caused by a defect in the genetic code for the machinery that is responsible for the glycine breakdown (called glycine cleavage enzyme). Amino acids are natural components of our body. Because glycine is not broken down, it accumulates in the body. Glycine is an important molecule in the brain where it has various functions such as transmitting signals from one brain cell to another. Excessive glycine disrupts the function of the brain.
Q: How does this affect children?
A: Children with NKH usually present as newborns, but 1 in 5 children presents in infancy. Typical symptoms include seizures, low tone, and severe problems with learning and development. This can profoundly affect a child’s ability to learn and to do normal things such as eating, sitting, and walking. The seizures can be so severe that they are hardly controlled despite the use of several medications for seizures. Not all children are equally affected. Most commonly children are severely affected and do not make developmental progress and have difficult to control seizures. Some children, about 1 in 6, are more mildly affected. They make progress in their development, and have seizures that can be controlled more easily.
Q: What is the severity?
A: There are four forms of this disorder: a relatively common neonatal form, an infantile form, a mild-episodic form, and a late-onset form. The elevated levels of glycine in the brain and CSF cause neurologic impairment which is seen almost immediately after birth. The prognosis is poor, and most patients die in the first few weeks of life. Those who survive have intractable seizures and poor neurodevelopmental outcomes.
Q: Is there treatment?
A: The disease is so rare that very little research has been done on it and only 2-3 doctors in the United States have studied it. There is no cure at this time and there are only a few known medications that can be given to assist in allowing those with the disease to have a comfortable life.
Q: What is the purpose of the John Thomas NKH Foundation?
A: The foundation was begun by concerned friends of a family with a child dealing with NKH. The goal is to help meet the needs of families affected by the disease as well as to provide funding for research of NKH.
Q: How can I help?
A: The John Thomas NKH Foundation is actively involved in creating events and fundraising opportunities for those who wish to be a part. Check out the Get Involved page to learn more. You will also be able to make donations in the near future.
John Thomas is a beautiful little boy born with NKH (nonketotic hyperglycemia). Like John Thomas, children with this disease are unable to process glycine as their bodies produce it, which can cause seizures and possible brain damage. The disease is extremely rare and has no known cure at this time. There are only a few known medications that allow those with the disease to have a comfortable life. Since very little is known, there is limited information on what the future holds for John Thomas and other children like him.
John Thomas recently celebrated his third birthday. Everyday for John Thomas is a blessing and he is loved by all around him. At this point, he still does not walk or talk but he is making progress daily. He plays with his toys as he scoots about the floor and flashes his big, happy smile constantly.
In the fall of 2015, John Thomas will begin preschool with special accommodations. Please check back periodically as we continue his story!