Notre Dame NKH Plasma Metabolism Study 

Non-ketotic hyperglycinemia (NKH) is a metabolic disease. We know that mutations in the NKH genes, glycine decarboxylase (GLDC) and aminomethyltransferase (AMT), lead to increase glycine, but are there other metabolic changes caused by these mutations. And if there are, why should we care? 

Human metabolism is an extremely complex network of interconnected pathways that is trying to achieve the overall goals of turning food into energy and making materials our bodies need to keep functioning. When one “pathway” or part of this network is lost, like the glycine cleavage pathway in NKH, other parts of the network change to try to compensate for this loss. Identifying changes that occur helps us to understand how the disease works and how to develop new therapies. 

We would like to study metabolic changes in NKH patients in two ways: 1) by analyzing metabolic data in patient records and 2) by doing an in-lab analysis of NKH patient blood. The metabolic data in patient records can give us an idea of the metabolic changes that occur in NKH patients over the past several years. The more records we have, the clearer the picture will be. Measurement of the metabolic changes in our lab provides a highly controlled environment so we can limit the amount of variation in the data. Ideally, we would like to analyze 30 NKH patient blood samples in comparison to 30 blood samples from healthy siblings or individuals that are roughly the same age as the NKH patients. 

Once we have found consistent metabolic changes in NKH patients, we will study these changes in our mouse models. For example, we can see what the effect of reversing those changes is and use this information to try to develop new therapies. In addition, it could help us better monitor how well our new gene therapy experiments are working in mouse models. It is possible that tracking more metabolites than just glycine will give us a better idea of the benefits of gene therapy in mice. 

Please help us continue our research by contributing medical records and blood samples. 

What do we need from participants/patients?

Medical Record Release forms

  1. Regardless if you have signed them for Notre Dame before or not, please re-sign these forms so that all participants in the ND NKH study will renew the consents on a yearly basis in the same month (March). The consents are only good for ONE YEAR.
  2. It is best to provide a release form for each clinic, hospital and lab that cares for your child.
  3. We are looking at all lab results especially Amino Acid Assay Results and Complete Metabolic panels but would also like to have any/all of other labs.

Informed consent for Blood

  1. I have attached an informed consent for skin, blood and stool. At this time, we are only interested in having patients give blood samples to us, possibly skin later.
  2. In order to obtain blood samples from patients, we will need to work with your physician and lab to get this coordinated. If your child is going in for blood work, it is a great time to obtain a bit more for our research.
  3. It is important for you to speak to your doctor about including this additional blood order for our study –one 5cc container.
  4. The blood will need to be placed on ice immediately and sent to us within 24 hours. We are happy to communicate with the lab ahead of time, to ensure this is possible. It is best not to have labs drawn on a Friday or Saturday, as we need to ensure staff is present to accept the specimen on our end.
  5. We will pay for all materials needed and shipping costs.


Please feel free to email Barb Calhoun at or call 574-631-8831 if you have any questions. Let me know when you are planning to have blood work and we can contact the lab to discuss logistics of sending the sample to us.

Thank you for your participation in our study.


Barb Calhoun, MSN, RN, NP

Joe Farris, graduate student, Haldar Lab

Kasturi Haldar, PhD

Download and Print your Consent and Medical Release Forms

In order to participate in this study you will need to provide ONE copy of the Natural History Study Consent Form.

You may either:

  1. Print your form, fill it out, scan it with a scanner or App, and email it to:
  2. Print your form, fill it out, and mail a hard copy to:
    193 Galvin Life Sciences Center
    Notre Dame, IN 46556

In order to participate in this study you will need to provide a medical release document for EACH doctor you wish to share records from. (i.e. one for genetics, one for neurology, one for PCP, etc.)

You may either:

  1. Print your forms, fill them out, scan it with a scanner or App, and email it to:
  2. Print your forms, fill them out, and mail hard copies to:
    193 Galvin Life Sciences Center
    Notre Dame, IN 46556