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NEB-Related Nemaline Myopathy Screening
NEB-related nemaline myopathy, also called Nemaline Myopathy 2, is part of a larger group of inherited muscle conditions. It causes weakness throughout the body, most noticeably in the face, neck, and torso.¹ About 1 in 108 people of Ashkenazi Jewish descent carry a change in the NEB gene that causes this condition.¹ Carriers are not expected to have symptoms, so most people don't realize they could pass the condition on to a child.¹ A carrier screen that includes the NEB gene looks for mutations that can cause nemaline myopathy 2 ahead of time, so you can understand your risk, ideally before pregnancy.
What is Nemaline Myopathy?
Nemaline myopathy is a rare genetic muscle condition named for tiny, thread-like structures called nemaline bodies that are visible when looking at muscle tissue under a microscope.² People with the condition have muscle weakness, low muscle tone, and reduced or absent reflexes.² Weakness is usually most noticeable in the face, neck, and torso.¹,²
Symptoms typically appear at birth or in early childhood.¹ Babies often experience delays in motor development (such as holding their head up, sitting, standing, or walking later than expected), and some have trouble with feeding, swallowing, and breathing.¹,² Other features can include a curved spine, foot differences, and stiff joints¹
While nemaline myopathy can be caused by mutations in at least 14 different genes, mutations in the NEB gene are most common and account for about 35% of cases.²,³ The most common form of NEB-related nemaline myopathy is the congenital form of the disease.²
Onset of the congenital form typically appears between birth and the first year of life.² In this form, muscle weakness does not usually progress or impact life expectancy.² Most people with this form of nemaline myopathy can lead full, active lives.³ Severity of disease is significantly variable from person to person.
There is currently no cure for nemaline myopathy.² Therapeutic treatment focuses on symptom management and often includes physical therapy, speech therapy, feeding therapy, and breathing support.²,³
NEB
NEB is one of the genes associated with nemaline myopathy. It is critical for muscle contraction.² NEB-related nemaline myopathy is inherited in an autosomal recessive pattern. This means a child has to inherit a non-working copy of the gene from each parent to be affected.² Someone with one working copy and one non-working copy is a carrier and usually won't have any symptoms.²
If both parents are carriers, each pregnancy has:
- A 25% chance the child inherits a non-working copy from each parent and is affected with NEB-related nemaline myopathy
- A 50% chance the child is an unaffected carrier, like the parents
- A 25% chance the child inherits two working copies and is unaffected and not a carrier
Why NEB-Related Nemaline Myopathy Carrier Screening Matters
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Carriers of NEB-related nemaline myopathy typically don't have symptoms, so there's no visible way to know that you can pass the genetic mutation on to a child.¹ Screening for NEB- related nemaline myopathy is recommended by the American College of Medical Genetics and Genomics (ACMG), ideally before pregnancy when you have the widest range of options.6
Your Odds of Carrying an NEB Gene Change
Your chance of being a carrier depends, in part, on your ancestry.¹ About 1 in 108 people of Ashkenazi Jewish descent carry a mutation in NEB.¹ One common mutation in the NEB gene appears frequently in the Ashkenazi Jewish population. This mutation results in nemaline myopathy that is present from birth.
Who Should Consider Screening
Genetic screening that includes NEB-related nemaline myopathy may be important to consider if any of these apply to you:
Ashkenazi Jewish Ancestry
With about 1 in 108 people of Ashkenazi Jewish descent carrying an NEB mutation, your heritage on its own can be reason enough to screen, even with no family history of the condition.¹ It's one of several Ashkenazi Jewish genetic diseases included in carrier screening.
Planning a Pregnancy
Knowing your carrier status before you conceive gives you important information while you still have the widest range of reproductive options. Here's more on
why screening before pregnancy matters.
A Partner who Carries an NEB Change
A child is at risk when both biological parents carry a mutation in the NEB gene.² If your partner has already screened positive, your own result is critical for understanding the risk for your future children.
Using a Sperm or Egg Donor
Reproductive carrier screening is still recommended when using an egg donor or a sperm donor to plan your family.
A Relative with Unexplained Muscle Weakness in Infancy
Babies with nemaline myopathy may have low muscle tone, feeding difficulties, and delays in motor development (such as sitting up, standing, or walking later than expected).² If a relative had muscle weakness like this as a baby and never received a clear diagnosis, it's worth mentioning to a genetic counselor.
How At-Home Genetic Testing Works
Order and register
Collect your sample
Return your sample
Get your results
Talk to a genetic counselor
Costs and Insurance Coverage
Insurance Billing
Self-Pay Option
Understanding Your Results
Positive (Carrier)
A positive result means that you are a carrier and have one working copy and one non-working copy of NEB. Carriers do not have the condition, but there is a chance of having a child with NEB-related nemaline myopathy when their partner is also a carrier. While most individuals who are carriers do not show signs or symptoms, there may be risks to their own health. If you are planning a pregnancy, your partner should be screened.
Negative Result
A negative result means that no mutation was detected, and you are unlikely to be a carrier for NEB-related nemaline myopathy. You should speak with a genetic counselor to ensure that you understand your risk and the risk to your children.
If You and Your Partner are Both Carriers
If you and your partner both carry a change in the NEB gene, each pregnancy has a 25% chance of being affected by nemaline myopathy 2.² Genetic counseling is strongly recommended for carrier couples. Every jscreen result comes with access to a board certified genetic counselor who can walk you through what your results mean and what your options are.
Plan for Your Family's Future with Confidence
Frequently Asked Questions
What Is Nemaline Myopathy Genetic Testing?
Nemaline myopathy genetic testing through jscreen is a carrier screen that looks for mutations in NEB, a gene that causes nemaline myopathy 2.¹ It tells you whether you carry one copy of a disease-causing mutation, which is most useful to know before pregnancy. For a full walkthrough of the process, see our complete guide to carrier screening.
Can Carrier Screening Show if I’m a Carrier of NEB-Related Nemaline Myopathy?
Yes. Carriers of NEB-related nemaline myopathy typically don't have any symptoms, so a carrier screen that includes the NEB gene can show if you have a mutation.¹ If you do, screening your partner is the next step in understanding the risk for a future child.
What Is an NEB Gene Mutation?
Two mutations in the NEB gene do not allow for certain muscle cells to work properly. Someone with one working copy and one non-working copy is known as a carrier and usually has no symptoms.² A child who inherits a non-working copy from each parent can be affected with nemaline myopathy.²
What Is the Life Expectancy with Nemaline Myopathy?
As there are multiple types of nemaline myopathy, disease severity varies by type. Across all types, life expectancy ranges from a few months to an average lifespan.³ The typical congenital form, most frequently seen when there is a mutation in the NEB gene, generally doesn't have a shortened lifespan.²,³
Is There a Cure for Nemaline Myopathy?
Not yet, but researchers continue to study the disease.²
How is Nemaline Myopathy Diagnosed?
When a child shows signs of muscle weakness, doctors review symptoms and personal/family history, and may order genetic testing if indicated.²
References
- Nemaline Myopathy 2. Norton & Elaine Sarnoff Center for Jewish Genetics. Revised July 2022. Accessed October 9, 2026.
https://www.jewishgenetics.org/genetic-disorders/search-genetic-disorders/nemaline-myopathy/ - Nemaline Myopathy. National Organization for Rare Disorders (NORD). Last updated October 15, 2024. Accessed October 9, 2026.
https://rarediseases.org/rare-diseases/nemaline-myopathy/ - Nemaline Myopathy. Cleveland Clinic. Last updated September 17, 2022. Accessed October 9, 2026.
https://my.clevelandclinic.org/health/diseases/24180-nemaline-myopathy - Lindqvist J, Ma W, Li F, et al. Triggering typical nemaline myopathy with compound heterozygous nebulin mutations reveals myofilament structural changes as pathomechanism. Nat Commun. 2020;11(1):2699. https://www.nature.com/articles/s41467-020-16526-9
- Coulson Z, Kolb J, Sabha N, et al. Generation of a novel mouse model of nemaline myopathy due to recurrent NEB exon 55 deletion. Skelet Muscle. 2025;15:8.
https://link.springer.com/article/10.1186/s13395-025-00378-2 - Gregg AR, Aarabi M, Klugman S, et al. Screening for autosomal recessive and X-linked conditions during pregnancy and preconception: a practice resource of the American College of Medical Genetics and Genomics (ACMG). Genet Med. 2021;23(10):1793-1806.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8488021/