What is (are) dopamine transporter deficiency syndrome ?
Dopamine transporter deficiency syndrome is a rare movement disorder. The condition is also known as infantile parkinsonism-dystonia because the problems with movement (dystonia and parkinsonism, described below) usually start in infancy and worsen over time. However, the features of the condition sometimes do not appear until childhood or later.  People with dopamine transporter deficiency syndrome develop a pattern of involuntary, sustained muscle contractions known as dystonia. The dystonia is widespread (generalized), affecting many different muscles. The continuous muscle cramping and spasms cause difficulty with basic activities, including speaking, eating, drinking, picking up objects, and walking.  As the condition worsens, affected individuals develop parkinsonism, which is a group of movement abnormalities including tremors, unusually slow movement (bradykinesia), rigidity, and an inability to hold the body upright and balanced (postural instability). Other signs and symptoms that can develop include abnormal eye movements; reduced facial expression (hypomimia); disturbed sleep; frequent episodes of pneumonia; and problems with the digestive system, including a backflow of acidic stomach contents into the esophagus (gastroesophageal reflux) and constipation.  People with dopamine transporter deficiency syndrome may have a shortened lifespan, although the long-term effects of this condition are not fully understood. Children with this condition have died from pneumonia and breathing problems. When the first signs and symptoms appear later in life, affected individuals may survive into adulthood.