Translocation Down Syndrome

Translocation Down syndrome is a rare type of Down syndrome. It occurs when your child has an extra part of or a whole extra chromosome 21. But the partial or extra chromosome 21 isn’t separate. Instead, it moves and then attaches or “translocates” to a different chromosome. People with this type of Down syndrome have the same distinct physical features and intellectual delays as people with typical Down syndrome.

Your child can inherit this type of Down syndrome. That means you can pass it onto your child through your genes. This happens when you’re a balanced translocation carrier of chromosome 21. But you don’t have signs of the condition yourself.

What are the symptoms of translocation Down syndrome?

Children with this condition usually have the same signs as typical Down syndrome.

Physical features of the condition may include:

• A flat face with a flat nose bridge
• Upward-slanting eyes
• A tongue that tends to stick out
• A short neck
• Small hands and feet
• Small pinky fingers
• A single line in the palm of each hand
• Weak muscle tone
• Short stature

Your child may also have certain cognitive challenges, including:

• Developmental delays
• Intellectual disability
• Learning disabilities

Translocation Down syndrome causes

Translocation Down syndrome occurs when a part of or a whole extra chromosome 21 gets “stuck” to another chromosome. It usually attaches to chromosome 14. As the cells divide, this extra chromosome continues to go along for the ride. This difference in your child’s chromosomes changes the way their brain and body develop.

Translocation Down syndrome is the only type that can be passed down (inherited) through genes. Most cases are random. But in about one-third of translocation Down syndrome cases, a biological parent is a carrier of the translocated chromosome.

Risk factors

If either biological parent is a carrier of translocation Down syndrome, that means you have a rearrangement of your genetic material, including chromosome 21. That increases your chance of having a child with the condition, even though you don’t have symptoms yourself (balanced translocation carrier).

To understand your risk of having a baby with Down syndrome, you may want to talk to a genetic counselor. They can help you understand how your genes can affect your baby’s health.

Complications of translocation Down syndrome

People with translocation Down syndrome have an increased risk of developing many additional health problems, including:

• Alzheimer’s disease
• Blood disorders
• Celiac disease
• Congenital heart disease
• Epilepsy
• Frequent infections
• Gum disease
• Hearing loss
• Mental health issues
• Obstructive sleep apnea
• Underactive thyroid
• Vision problems

8How doctors diagnose translocation Down syndrome

Your healthcare provider may be able to diagnose translocation Down syndrome before or after birth.

Before birth

Your provider will offer you prenatal genetic testing during your pregnancy to look for genetic conditions. Genetic testing is always your decision.

Screening tests

Screening tests can show how likely you are to have a baby with Down syndrome. But they can’t determine a diagnosis for sure. These tests are safe, and they may help you decide if you want diagnostic testing. Screening tests include:

• Nuchal translucency
• NIPT test

Diagnostic tests

Diagnostic tests can confirm a Down syndrome diagnosis. These tests have more risks involved because they’re more invasive. Diagnostic tests include:

• Amniocentesis
• Chorionic villus sampling (CVS)
• Cordocentesis

After birth

When your baby is born, their healthcare provider will look for the physical signs of Down syndrome during an exam. To confirm the diagnosis, your baby may get a genetic test called a karyotype. For this test, your baby’s provider will take a small blood sample. They’ll send it to a lab for a pathologist to look for signs of the condition.

How is translocation Down syndrome treated?

Translocation Down syndrome treatment focuses on managing your child’s symptoms and helping them thrive. Your child may need treatment for the physical effects and complications of the condition. This may include:

• Surgery for birth defects
• Hearing aids or eyeglasses to help them hear or see
• Gluten-free eating plan for celiac disease
• Medication to treat heart disease

Most children with translocation Down syndrome will also need some support reaching their developmental milestones. They may benefit from certain early interventions to help them reach their full potential. These may include:

• Occupational therapy
• Physical therapy
• Speech therapy

What is the outlook (prognosis) for my child?

Children with translocation Down syndrome have a very good outlook. They may need certain medical treatments or supportive care. But they usually reach their milestones and do the same things typical children do. From going to school and making friends to participating in sports, children with translocation Down syndrome can and do thrive.

What is the life expectancy of translocation Down syndrome?

On average, people with translocation Down syndrome live to age 60 or older. Advances in medical care over the past several decades have enabled people with the condition to live rather typical lives. Some need additional support and medical care. But most people with Down syndrome have the ability to live happy, healthy lives.

What’s the difference between translocation and mosaic Down syndrome?

Translocation Down syndrome and mosaic Down syndrome are both rare types of Down syndrome. They both involve the 21st chromosome.

Translocation Down syndrome occurs when an extra part of or a whole extra chromosome 21 attaches to another chromosome. Mosaic Down syndrome occurs when some cells have three copies of chromosome 21, and others have the usual two copies.

Is translocation Down syndrome less severe?

Translocation Down syndrome and typical Down syndrome (trisomy 21) produce the same range of severity. Mosaic Down syndrome may produce less severe signs and symptoms because some of the cells involved have the usual two copies of chromosome 21.