Susan E. Swedo

Psychiatric Disorders in First Degree Relatives of Children and Adolescents with Obsessive Compulsive Disorder

One hundred and forty-five first-degree relatives (89 parents [96%] and 56 siblings [98%]) of 46 children and adolescents with severe primary obsessive compulsive disorder (OCD) were personally interviewed with clinical and structured psychiatric interviews. Parent interviews were scored by a rater blind to proband diagnosis. Thirty percent of probands had at least one first-degree relative with OCD: 25% of fathers and 9% of mothers received this diagnosis. Forty-five percent of fathers and 65% of mothers received one or more other psychiatric diagnoses. The increased familial rate of OCD over that expected from a general population, and over that found in parents of conduct disordered patients, is consistent with a genetic factor in OCD. Presenting obsessive compulsive symptoms of probands and their parents were usually dissimilar, arguing against any simple social or cultural transmission.

Brain human monoclonal autoantibody from sydenham chorea targets dopaminergic neurons in transgenic mice and signals dopamine D2 receptor: implications in human disease.

How autoantibodies target the brain and lead to disease in disorders such as Sydenham chorea (SC) is not known. SC is characterized by autoantibodies against the brain and is the main neurologic manifestation of streptococcal-induced rheumatic fever. Previously, our novel SC-derived mAb 24.3.1 was found to recognize streptococcal and brain Ags. To investigate in vivo targets of human mAb 24.3.1, VH/VL genes were expressed in B cells of transgenic (Tg) mice as functional chimeric human VH 24.3.1–mouse C-region IgG1a autoantibody. Chimeric human–mouse IgG1a autoantibody colocalized with tyrosine hydroxylase in the basal ganglia within dopaminergic neurons in vivo in VH 24.3.1 Tg mice. Both human mAb 24.3.1 and IgG1a in Tg sera were found to react with human dopamine D2 receptor (D2R). Reactivity of chorea-derived mAb 24.3.1 or SC IgG with D2R was confirmed by dose-dependent inhibitory signaling of D2R as a potential consequence of targeting dopaminergic neurons, reaction with surface-exposed FLAG epitope-tagged D2R, and blocking of Ab reactivity by an extracellular D2R peptide. IgG from SC and a related subset of streptococcal-associated behavioral disorders called “pediatric autoimmune neuropsychiatric disorder associated with streptococci” (PANDAS) with small choreiform movements reacted in ELISA with D2R. Reaction with FLAG-tagged D2R distinguished SC from PANDAS, whereas sera from both SC and PANDAS induced inhibitory signaling of D2R on transfected cells comparably to dopamine. In this study, we define a mechanism by which the brain may be altered by Ab in movement and behavioral disorders.