Learn more about
Arginase 1 Deficiency

Arginase 1 Deficiency (ARG1-D) is an inherited metabolic disorder affecting children, teens, and adults. It is characterized by high levels of plasma arginine.

If your family is facing the challenges of ARG1-D or a possible diagnosis, you are not alone. The ARG1-D community and your local metabolic center are here to help.

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ARG1-D is a type of urea cycle disorder (UCD) that impacts a person’s health over time. This rare disease affects not only the person who has been diagnosed, but also their family and loved ones.

It takes a community to support families like yours. The ARG1-D community is made up of patients, caregivers, and family members who are also managing this condition and may be able to help you learn more.

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Understanding ARG1-D

Facts you should know

  • ARG1-D is caused by the body’s inability to break down arginine in the urea cycle
  • Arginine builds up in the body, impacting a person’s ability to do the basic tasks of everyday life
  • Symptoms usually appear between 2 and 4 years of age and continue to progress into adulthood
  • In some cases, symptoms can appear after puberty

Talk to your doctor if your child or loved one may be showing symptoms of ARG1-D

In people with ARG1-D, arginine builds up over time, reaching high and unhealthy levels in the blood plasma

Signs and symptoms of the disease


Intellectual delay

Missed developmental milestones

Muscle tightness (spasticity)

Josh is living with ARG1-D.

Diagnosis and detection of ARG1-D

Early detection of ARG1-D is critical and can help your child get the treatment they need

You may need a combination of tests:

  • Newborn screening (not required or provided in all states)
  • A blood test for amino acids to see if high levels of arginine are present
  • Genetic testing which can confirm an ARG1-D diagnosis

ARG1-D can often be detected by newborn screening, but that isn’t required or provided in all states. Also, sometimes ARG1-D can be missed, or misdiagnosed as another condition, such as cerebral palsy, or hereditary spastic paraplegia. That’s why testing is so important for early detection.

A free amino acid blood test and genetic test can be ordered by a doctor for eligible patients through ThinkArginine.com

To get testing information and to have your doctor order a test kit, refer them to this website

Damian is living with ARG1-D.

Managing ARG1-D

Currently, this condition is managed by restricting diet and by adding supplements and medications as prescribed by your healthcare team

Restricting diet can be a challenge for many families managing ARG1-D. Fortunately, there are people to help. Your care team may include a dietitian, who can help you plan meals and shopping trips.

Resources for you and your family

These resources and tools can help you understand and manage ARG1-D

Patient Brochure

Learn about managing ARG1-D with this free booklet

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Protein Management Tools

Protein management is crucial; these tools can be helpful

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Traditional Shopping List

A list of items, broken out by food groups, to help with your dietary plan

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Photo Shopping List

An illustrated checklist to help you plan your next shopping trip

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Try these quick and easy recipes that fit the dietary restrictions

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Nutrition Label Guide

Tips to help you read food labels and choose the right foods to meet your nutritional goals

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The ARG1-D community is here to help

While ARG1-D is a rare condition, patients and families do not have to face it alone

There is an established community of patients, caregivers, doctors, and nurses who are ready to support you. Click on any of the organizations below to learn more.

Looking for more help with ARG1-D?
Here’s a great place to start

The ARG1-D community
A world of help and hope

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Connect with the ARG1-D community to receive educational resources and tools. You can also get information about webinars in both English and Spanish, and participate in market research studies.

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