creatine transporter deficiency

What is Creatine Transporter Deficiency?

Creatine transporter deficiency (CRTR deficiency) is a condition characterized by intellectual disability. It is caused by harmful genetic changes (variants) in the SLC6A8 gene. Individuals with this disorder cannot move a substance called creatine throughout the body, which is needed to produce energy for brain and muscle cells. Because of this, these cells do not have enough energy to function properly, which results in the symptoms of the condition. CRTR deficiency is inherited in an X-linked manner. This means the condition is typically more severe in individuals assigned male at birth (XY). However, individuals assigned female at birth (XX) may also have symptoms of the condition.

The symptoms of CRTR deficiency are usually noticed in infancy or early childhood. The first signs of the condition are developmental delays in crawling, walking, and talking. The most common symptom of this disorder is intellectual disability. Other symptoms can include behavioral issues (such as autism or attention deficit hyperactivity disorder), low muscle tone (hypotonia), abnormal movements, digestive problems, distinct facial features, and heart problems.

Additional considerations for carriers

XX individuals (who are typically assigned female at birth) are carriers of CRTR deficiency. Carriers may exhibit symptoms (such as intellectual disability). Symptoms reported in carriers generally are much milder than those in XY individuals.

How common is Creatine Transporter Deficiency?

The exact incidence of CRTR deficiency is unknown. Approximately 150 individuals have been diagnosed worldwide.

How is Creatine Transporter Deficiency treated?

There is no cure for CRTR deficiency. Some people with the disorder can improve their symptoms by taking creatine and other nutritional supplements by mouth. Medications may be used to manage seizures, behavioral issues, and abnormal movements. Beginning at a young age, individuals diagnosed with CRTR deficiency may benefit from receiving speech, physical, occupational, and behavioral therapies, as well as other supportive services.

What is the prognosis for an individual with Creatine Transporter Deficiency?

The prognosis depends on the severity of an individual’s symptoms. Reports of individuals with CRTR living into their sixties indicate that a normal life expectancy is possible. All individuals assigned male at birth with CRTR deficiency are expected to have an intellectual disability. Many cannot speak in complete sentences and need help with activities of daily living, such as dressing and feeding. They are not usually able to live independently.