Dopamine Transporter Deficiency Syndrome
Dopamine transporter deficiency syndrome (DTDS) is a rare movement disorder that causes progressive (worsening) dystonia and parkinsonism. It usually begins in infancy ('classic DTDS') and for this reason, it is also known as 'infantile parkinsonism dystonia.' However, some people with DTDS may not develop symptoms until childhood or later (which is known as 'atypical DTDS').
The dystonia in DTDS is characterized by uncontrollable (involuntary), long-lasting muscle contractions and cramps that involve many different muscles. Dystonia causes difficulty with daily activities and impairs the ability to talk, eat, drink, pick up objects, and walk. Parkinsonism develops as the disorder progresses and is characterized by tremor (shaking), slowed movements (bradykinesia), rigidity (stiffness), and impaired balance and coordination. Additional symptoms that may be present include abnormal eye movements, reduced facial expressions, irritability, sleeping problems, digestive problems (such as reflux or constipation), and recurrent pneumonia which can be life-threatening. Classic DTDS is associated with a poor outlook (prognosis), and death may occur in the teenage years due to unexplained sudden causes or respiratory complications. Those with atypical DTDS may have milder symptoms and a longer lifespan, but the long-term outlook for this form is not well-known.
DTDS is caused by mutations in the SLC6A3 gene and inheritance is autosomal recessive. There is no cure for DTDS; treatment aims to relieve symptoms and increase quality of life. Treatment may include medicines to control involuntary movements (such as tetrabenazine and benzodiazepines), medicines to control dystonia (such as pramipexole and ropinirole), and physical therapy to reduce the risk of contractures from muscle rigidity.
The dystonia in DTDS is characterized by uncontrollable (involuntary), long-lasting muscle contractions and cramps that involve many different muscles. Dystonia causes difficulty with daily activities and impairs the ability to talk, eat, drink, pick up objects, and walk. Parkinsonism develops as the disorder progresses and is characterized by tremor (shaking), slowed movements (bradykinesia), rigidity (stiffness), and impaired balance and coordination. Additional symptoms that may be present include abnormal eye movements, reduced facial expressions, irritability, sleeping problems, digestive problems (such as reflux or constipation), and recurrent pneumonia which can be life-threatening. Classic DTDS is associated with a poor outlook (prognosis), and death may occur in the teenage years due to unexplained sudden causes or respiratory complications. Those with atypical DTDS may have milder symptoms and a longer lifespan, but the long-term outlook for this form is not well-known.
DTDS is caused by mutations in the SLC6A3 gene and inheritance is autosomal recessive. There is no cure for DTDS; treatment aims to relieve symptoms and increase quality of life. Treatment may include medicines to control involuntary movements (such as tetrabenazine and benzodiazepines), medicines to control dystonia (such as pramipexole and ropinirole), and physical therapy to reduce the risk of contractures from muscle rigidity.