What is Christianson syndrome?

Christianson syndrome is a rare genetic disorder. It causes severe problems with your nervous system.

People with this condition have trouble walking and speaking. They typically also have developmental delays or intellectual disabilities. People with Christianson syndrome often start showing symptoms of the condition when they’re infants.

Who does Christianson syndrome affect?

Christianson syndrome mostly affects men and people assigned male at birth (AMAB). The condition is an “X-linked genetic disorder.” This means it occurs because of a change (mutation) in X chromosomes.

Why does Christianson syndrome only affect males?

Women and people assigned female at birth (AFAB) have two X chromosomes, while men and people AMAB have one X chromosome and one Y chromosome.

If a person AFAB has the mutation that causes Christianson syndrome on one X chromosome, they still have one functioning X chromosome. Because of this, they aren’t likely to develop Christianson syndrome.

If a person AMAB has the gene mutation, they have no other X chromosome to take over typical functions. They’ll develop Christianson syndrome. For a person AFAB to develop Christianson syndrome, they’d have to have gene mutations on both X chromosomes, which is extremely rare.

How common is Christianson syndrome?

Experts don’t know exactly how many people have Christianson syndrome. They do know it’s extremely rare.

By some estimates, about 1 in 600 boys have an X-linked intellectual disability. One study found Christianson syndrome in about 1 in 100 families who had a child with an X-linked developmental disability.

What are the symptoms of Christianson syndrome?

Most people with Christianson syndrome who were also assigned male at birth have:

• Balance and movement issues (ataxia).
• Epilepsy.
• Eye problems such as strabismus (crossed eyes).
• Inability to speak.
• Intellectual disability.
• Unusually small head (microcephaly).

Some people also have:

• Autism spectrum disorder.
• Cerebellar atrophy, when the part of their brain that controls posture and balance stops growing or gets smaller.
• Gastrointestinal symptoms, such as gastroesophageal reflux disease (GERD).
• Loss of walking skills.
• Low muscle tone (hypotonia).
• Low weight or short stature.

People with Christianson syndrome often have symptoms similar to those of Angelman syndrome. They may seem happy all the time or laugh often for no apparent reason.

Women and people AFAB who have the gene mutation often have learning disabilities. But they typically don’t have any other Christianson syndrome symptoms.

What causes Christianson syndrome?

Christianson syndrome is a genetic disorder, meaning it occurs because of a gene mutation. Christianson syndrome happens when someone is born with a mutation in their SLC9A6 gene, a gene in their X chromosome.

This gene mutation is passed down from parent to child. Usually, parents who pass down the mutation are carriers of Christianson syndrome, meaning they have the gene change but don’t have any symptoms of the condition themselves.

How is Christianson syndrome diagnosed?

Your healthcare provider may suspect Christianson syndrome if you or your child has several of its symptoms. They use a blood test to diagnose or rule out Christianson syndrome. This blood test checks for the SLC9A6 gene mutation.

How is Christianson syndrome treated?

Christianson syndrome treatment focuses on decreasing symptoms and improving quality of life. You or your child’s treatment plan may include:

• Eyeglasses, contact lenses or surgery to improve vision or correct crossed eyes.
• Individualized education plans to help children with intellectual or learning disabilities.
• Medications to decrease the number and severity of seizures.
• Physical therapy to increase strength, muscle tone or walking skills.
• Speech therapy to improve language and communication skills.

How can I prevent Christianson syndrome?

There’s no way to prevent Christianson syndrome or the gene mutation that causes it. If you suspect you have or are a carrier for Christianson syndrome, you may choose to have genetic testing.

In genetic testing, you give a blood sample to look for certain gene mutations. A genetic counselor reviews the blood test results with you. They help you understand the implications of gene mutations, including your chances of having a child with Christianson syndrome.

What is the outlook for Christianson syndrome?

With supportive treatments, people with Christianson syndrome can live a higher quality of life. Research about Christianson syndrome is ongoing, and experts don’t have significant data on life expectancy.

Many people with Christianson syndrome live a typical lifespan, although they may experience regression. In regression, speaking or walking skills improve for a period and then worsen.

What questions should I ask my healthcare provider?

If you or your child has suspected or has been diagnosed with Christianson syndrome, you may ask your healthcare provider:

• What tests diagnose Christianson syndrome?
• What causes Christianson syndrome?
• What are the treatment options for Christianson syndrome?
• What can I do to improve my quality of life with Christianson syndrome?
• What are the chances that I’ll pass Christianson syndrome to my children?

A note from Cleveland Clinic

Christianson syndrome is a rare genetic disorder. It causes severe nervous system issues, including difficulty walking or speaking. Most people with the condition also have some level of intellectual disability. Christianson syndrome mostly occurs in men and people assigned male at birth (AMAB) Although there’s no cure, treatment can improve your overall quality of life.