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PubMed This is a summary of 42 peer-reviewed journal articles Updated
Neurology

Corpus Callosum Agenesis-Neuronopathy Syndrome: A Patient Guide

At a Glance

Andermann syndrome is a genetic disorder caused by disease-causing changes in both copies of SLC12A6. It affects the brain and peripheral nerves, but movement, learning, development, and severity vary widely, so care must be individualized and ongoing.

Corpus Callosum Agenesis-Neuronopathy Syndrome, often referred to as Andermann syndrome, is a complex genetic condition that affects the development and function of both the central and peripheral nervous systems. At its core, the condition is caused by biallelic pathogenic or likely pathogenic variants in the SLC12A6 gene. This gene provides instructions for a protein called KCC3, a potassium-chloride cotransporter that manages the balance of salt and water within nerve cells. It is believed that impaired ion and cell-volume regulation from a defective KCC3 transporter contributes to abnormal nerve function and degeneration [1][2].

The condition is named for two hallmark features: the absence or underdevelopment of the corpus callosum (the bridge between the brain’s hemispheres) and neuronopathy (damage to the peripheral nerves that control movement and sensation). However, modern clinical experience has shown that the syndrome is far more variable than its name suggests. While some children face significant physical and intellectual challenges from infancy, others may have a completely intact corpus callosum and follow a much milder clinical course [3]. This spectrum of severity means that a diagnosis is not a fixed blueprint, but rather a starting point for understanding a child’s unique needs [4].

Because the syndrome affects multiple systems—impacting how a child moves, learns, and physically develops—the standard of care focuses on comprehensive, multidisciplinary support. This approach brings together specialists in neurology, physical therapy, and respiratory health to manage symptoms and maintain independence for as long as possible [5]. While the progressive nature of the condition requires ongoing monitoring and adaptation, the primary goal of care is to maximize each child’s potential and comfort. Navigating this diagnosis involves shifting the focus from generalized statistics to the individual child, ensuring they have the specialized support necessary to engage with the world around them [6].

In this guide

6 chapters

01

Understanding Andermann Syndrome

Learn what Andermann syndrome means for your child, including SLC12A6 genetics, brain and nerve symptoms, MRI findings, therapies, and family care planning.

02

Symptoms and Warning Signs

Learn the symptoms of Andermann syndrome, from low muscle tone and muscle wasting to swallowing, breathing, sensory, movement, and seizure warning signs.

03

The Genetics of SLC12A6

Learn how SLC12A6 causes Andermann syndrome, how autosomal recessive inheritance works, what an intact corpus callosum means, and when genetic counseling helps.

04

Diagnosis and Testing Results

Learn how Andermann syndrome is diagnosed using brain MRI, nerve conduction studies, EMG, and SLC12A6 testing, including what variants and lab results mean.

05

Care and Daily Management

Learn how families manage Andermann syndrome with therapy, breathing and swallowing checks, pain support, mobility aids, and anesthesia planning for children.

06

Long-Term Outlook and Progression

Learn how Andermann syndrome may progress, what to expect for mobility and cognition, and how breathing, nutrition, and supportive care shape each child’s outlook.

Common questions in this guide

What causes Andermann syndrome?
Andermann syndrome is caused by disease-causing or likely disease-causing variants in both copies of the SLC12A6 gene. These changes can impair KCC3, a protein that helps nerve cells regulate salt, water, and cell volume.
What difficulties can children with Andermann syndrome experience?
Children may have challenges with movement, sensation, learning, intellectual development, or physical development. The range is broad: some have major challenges from infancy, while others have a milder course.
Does every child with Andermann syndrome have an underdeveloped corpus callosum?
No. Although the syndrome’s name refers to an absent or underdeveloped corpus callosum, some children have a fully present corpus callosum. The presence or absence of this structure is one part of understanding a child’s needs, not a complete description of the condition.
What kind of medical support does a child with Andermann syndrome need?
Care is usually coordinated across neurology, physical therapy, and respiratory health services. Ongoing monitoring and adjustments can help manage symptoms, support development, maintain independence, and promote comfort.
What can families expect after an Andermann syndrome diagnosis?
The condition can be progressive, but its severity and clinical course vary widely from child to child. A diagnosis is a starting point for individualized monitoring and support rather than a fixed prediction of a child’s abilities or future.
How does Andermann syndrome affect family planning?
The condition results from changes in both copies of the SLC12A6 gene, so families should ask a genetics professional to explain how it was inherited and what the results mean for future pregnancies. Family-specific risk cannot be determined without reviewing the child’s genetic findings and family history.

Get notified when new evidence is published on Corpus callosum agenesis-neuronopathy syndrome.

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References

References (6)
  1. 1

    A role for KCC3 in maintaining cell volume of peripheral nerve fibers.

    Flores B, Schornak CC, Delpire E

    Neurochemistry international 2019; (123()):114-124 doi:10.1016/j.neuint.2018.01.009.

    PMID: 29366908
  2. 2

    KCC3 axonopathy: neuropathological features in the central and peripheral nervous system.

    Auer RN, Laganière JL, Robitaille YO, et al.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2016; (29(9)):962-76 doi:10.1038/modpathol.2016.90.

    PMID: 27230413
  3. 3

    A Novel Splice-Site Variant in SLC12A6 Causes Andermann Syndrome without Agenesis of the Corpus Callosum.

    Al Shibli N, Al-Maawali A, Elmanzalawy A, et al.

    Journal of pediatric genetics 2020; (9(4)):293-295 doi:10.1055/s-0039-1700975.

    PMID: 32765936
  4. 4

    Expanding the phenotype of SLC12A6-associated sensorimotor neuropathy.

    Bogdanova-Mihaylova P, McNamara P, Burton-Jones S, Murphy SM

    BMJ case reports 2021; (14(10)) doi:10.1136/bcr-2021-244641.

    PMID: 34706912
  5. 5

    An Overview of Congenital Myopathies.

    Mah JK, Joseph JT

    Continuum (Minneapolis, Minn.) 2016; (22(6, Muscle and Neuromuscular Junction Disorders)):1932-1953 doi:10.1212/CON.0000000000000404.

    PMID: 27922501
  6. 6

    Distal Myopathies.

    Felice KJ

    Neurologic clinics 2020; (38(3)):637-659 doi:10.1016/j.ncl.2020.03.007.

    PMID: 32703474

This page is for informational purposes only and does not constitute medical advice. Your child’s neurologist and multidisciplinary care team should interpret genetic results and tailor monitoring and support to your child’s needs.