<Tr> <Td_colspan="2"> Streptococcus pyogenes (stained red), a common group A streptococcal bacterium . PANDAS is hypothesized to be an autoimmune condition in which the body's own antibodies to streptococci attack the basal ganglion cells of the brain, by a concept known as molecular mimicry . </Td> </Tr> <Tr> <Th> Specialty </Th> <Td> Neurology </Td> </Tr> <P> Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) is a hypothesis that there exists a subset of children with rapid onset of obsessive - compulsive disorder (OCD) or tic disorders and these symptoms are caused by group A beta - hemolytic streptococcal (GABHS) infections . The proposed link between infection and these disorders is that an initial autoimmune reaction to a GABHS infection produces antibodies that interfere with basal ganglia function, causing symptom exacerbations . It has been proposed that this autoimmune response can result in a broad range of neuropsychiatric symptoms . </P> <P> The PANDAS hypothesis was based on observations in clinical case studies at the US National Institutes of Health and in subsequent clinical trials where children appeared to have dramatic and sudden OCD exacerbations and tic disorders following infections . There is supportive evidence for the link between streptococcus infection and onset in some cases of OCD and tics, but proof of causality has remained elusive . The PANDAS hypothesis is controversial; whether it is a distinct entity differing from other cases of Tourette syndrome (TS) / OCD is debated . </P>

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