An observational study in Metabolic Disease, Propionic Acidemia and Organic Acidemia, sponsored by National Human Genome Research Institute (NHGRI). Recruiting at 2 sites in United States. Open to participants aged 1 Month to 100 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by National Human Genome Research Institute (NHGRI) · Observational
Background:
People s bodies need to break down food into the chemicals. These chemicals are used for energy and growth. Some people cannot process all chemicals very well. Too much of some chemicals can cause diseases. One of these diseases is called propionic acidemia (PA). People with PA can have problems with growth, learning heart, abdomen, and other organs. Researchers want to better understand how these problems happen.
Objective:
To learn more about propionic acidemia and the genes that might contribute to it.
Eligibility:
People at least 2 years old with PA who can travel to the clinic
Some unaffected family members
Design:
Participants will have a 3 to 5-day hospital visit every year or every few years. Family members may have just 1 visit.
During the family member visit, they may have:
Medical history
Physical exam
Samples of blood and urine
Questions about diet and a food diary
Doctors and nurses may do additional studies:
Samples of saliva, skin and stool
Fluid from a gastronomy tube, if participants have one
Dental and eye evaluations
A kidney test - a small amount of dye will be injected and blood will be collected.
Consultations with specialists
A test of calories needed at rest. A clear plastic tent is placed over the participant to measure breathing.
Stable isotope study. Participants will take a nonradioactive substance then blow into a bag.
Photos taken of the face and body with underwear on
Ultrasound of the abdomen
Heart tests
Hand x-ray
Brain scan
Participants may have other tests if study doctors recommend them. They will get the results of standard medical tests and genetic tests.
...
Propionic acidemia (PA) is one of the most common inborn errors of organic acid metabolism. Although this disorder is now routinely detected in the immediate neonatal period on the US newborn screen, clinical outcomes are poor despite timely and aggressive medical intervention. Worldwide, the incidence of PA varies widely. The estimated live-birth incidence of PA is 1:243,000 in the US, 1:166,000 in Italy and 1:250,000 in Germany. Affected patients are medically fragile and can suffer from complications such as failure to thrive, intellectual disability, basal ganglia strokes, seizures, cardiomyopathy, cardiac arrhythmias, pancreatitis, impaired gut motility, osteoporosis and hematological complications. The frequency of these complications in the US patients and their precipitants remain poorly understood. Furthermore, current treatment outcomes have continued to demonstrate substantial morbidity and mortality in the patient population. Specific treatments include dietary modification to reduce propiogenic precursor load, levocarnitine to facilitate excretion of propionate, and oral antibiotics to suppress propionogenic gut flora. More recently, solid organ transplantation (liver and/or kidney) has been used to treat PA patients experiencing frequent and severe episodes of metabolic instability. However, optimal transplant strategy and post-transplant management have not been delineated. Several survey-based and retrospective studies describing the natural history of propionic acidemia have been published in the last decade. While these publications added to our understanding of the clinical course of this disease, these studies have not systematically focused on the US population using prospective analysis and reflect largely European experience, where many developed countries do not routinely screen for PA using newborn screen. Thus, the benefits of newborn screening on the PA outcomes require further clarification.
Under proposed NIH protocol, we will prospectively evaluate patients with propionic acidemia with special emphasis on the US population. Typical inpatient admissions and outpatient evaluations will last up to 4-5 days and may involve blood drawing, urine collection, stool collections, genomic studies, ophthalmological examination, cardiology evaluation, radiological procedures, brain and cardiac MRI/MRS, dietary assessment and neurobehavioral evaluation. In some patient s skin biopsies will be pursued.
The study objectives will be to describe the natural history of propionic acidemia in the US patients by delineating the spectrum of phenotypes and querying for genotype, enzymology, microbiome, and phenotype correlations. The population will consist of patients previously evaluated at NIH, physician referrals, and families directed to the study from clinicaltrials.gov, Organic Acidemia Association and Propionic Acidemia Foundation. Patients will be evaluated at the NIH Clinical Center or via telehealth platforms supported by NIH. Outcome measures will largely be descriptive and encompass correlations between clinical, microbiological, biochemical and molecular parameters.
23 studies on the registry are indexed under Propionic Acidemia; 8 are open to participants now.
This study's planned enrollment of 1,045 is above the median of 78 across 10 observational studies indexed under Propionic Acidemia.
Browse Propionic Acidemia studies →National Human Genome Research Institute (NHGRI) is the lead sponsor of 203 studies on the registry; 33 are open to participants now.
Compared within Propionic Acidemia, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Metabolic Diseases. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Patients with Propionic Acidemia
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
However, no tests or procedures that are greater then minimal risk will be performed. Affected subjects who are pregnant may undergo procedures as part of their clinical care, including blood draws, genetic studies, and consultations, according to the clinical judgement of the clinical team. However, pregnant participants will be excluded from procedures such as organ tissue collection, stable isotope studies, testing, and brain or cardiac MRI until the pregnancy is concluded.
EXCLUSION CRITERIA:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients with Propionic Acidemia, standard adult, parental permission
Healthy Volunteers, standard adult, parental permission
Unaffected family members
Natural history to asess long term complications of Propionic Acidemia
assessing the long term complications of Propionic Acidemia during a week long evaluation with imaging, labs, and consultations.
Time frame: Ongoing
Plan to share: No — Study is observational natural history study that is ongoing with no defined endpoints
Started Nov 2016 (actual). Primary completion is estimated for Aug 2036, 237 months after the start.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
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National Human Genome Research Institute (NHGRI) →