What Does NxGen MDx Screen For?

We screen for up to 120 genetic disorders that can affect your pregnancy, the health of your baby, and your family's future. You can learn more about our various screens — and which sets of screens (or "panels") align with where you are in your reproductive journey.

What Does NxGen MDx Screen For?

3-Hydroxy-3-Methylglutaryl- CoA (HMG-CoA) Lyase Deficiency

What Your Test Results Mean:

Test results indicate that you are a carrier of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase deficiency. Carriers are not expected to show symptoms. You and your partner would both have to be carriers of HMG-CoA lyase deficiency for there to be an increased chance to have a child with symptoms; this is known as autosomal recessive inheritance. Carrier testing of your partner or donor is recommended in addition to consultation with a genetic counselor for a more detailed risk assessment.

Since this is an inherited gene change, this information may be helpful to share with family members as it may impact their family planning.

Disease Explained:

HMG-CoA lyase deficiency is an uncommon inherited disorder in which the body cannot process a particular protein building block called leucine, and the body is prevented from making ketones, which are compounds that are used for energy during periods without food (fasting). The signs and symptoms of HMG-CoA lyase deficiency usually appear within the first year of life and include episodes of vomiting, diarrhea, dehydration, lethargy, and weak muscle tone (hypotonia). During an episode, blood sugar levels can become dangerously low, and a buildup of harmful compounds can cause the blood to become too acidic (metabolic acidosis). If untreated, the disorder can lead to breathing problems, convulsions, coma, and death. Episodes are often triggered by an infection, fasting, strenuous exercise, or other types of stress.


Prognosis is good with early diagnosis and prompt treatment. However, this condition can be fatal in approximately 20 percent of cases. Repeated crises may result in brain damage and significant learning/intellectual disabilities. Symptoms typically become milder after childhood; however, long-term effects may include heart damage, pancreatitis, vision loss, hearing loss, and intellectual disability.


Treatment includes avoiding fasting, feeding with a low-leucine diet, medications, and prompt attention during metabolic crises. Individuals are often followed by a physician specializing in metabolism.

Which Screens Are Right for You?

Determining which screens or set of screens are right for you will depend on where you are in your reproductive journey. Tell us where you are today so you can learn more about how to move forward tomorrow.

Planning to Have a Baby Already Expecting
Which Screens Are Right for You?

Talk to a Genetic Counselor

As a NxGen client, you'll have access to personal genetic counselors who can help explain the results of your screens and provide insight on how to move forward. To schedule a personal conference to discuss your screen results, call (855) 776-9436. or click the link below.

Discuss Your Screening Results