Pediatric autoimmune neuropsychiatric disorders associated with Streptococcus in identical siblings

Baseline characteristics of children in the International PANS Registry (IPR) Epidemiology Study

PURPOSE

The International PANS Registry (IPR) Epidemiology Study is a registry-based, longitudinal study. We designed this study to improve phenotyping and characterisation of children with paediatric acute-onset neuropsychiatric syndrome (PANS) and PANS-like features and facilitate multidisciplinary and translational health research. This cohort provides new opportunities to address unresolved research questions related to the broad spectrum of heterogenous PANS-like conditions.

PARTICIPANTS

Inclusion in the IPR Epidemiology Study remains open indefinitely via IPR enrolment online. Participants include children with PANS or who have PANS-like features and their healthy siblings. We collected cross-sectional survey data based on parent report, including details on phenotypic traits and characteristics that, to our knowledge, have not been previously collected for this patient population. We describe the baseline characteristics of cases and their healthy siblings here.

FINDINGS TO DATE

The IPR Epidemiology Study currently includes 1781 individuals (1179 cases, 602 siblings; from 1010 households). Many households include a sibling (n=390, 39%) and some include multiple cases (n=205, 20%). Mean enrolment age was 11.3±4.3 years for cases and 10.1±5.3 for siblings. Leading PANS-like features include anxiety (94%), emotional lability (92%) and obsessions (90%). Onsets were sudden and dramatic (27%), gradual with a subsequent sudden and dramatic episode (68%) or a gradual progression (5%). The mean age at early signs/symptom onset was 4 years and 7 years at sudden and dramatic increases, respectively. Infection/illness was the most common suspected symptom trigger (84%). Nearly all cases had been treated with antibiotics (88%) and/or non-steroidal anti-inflammatory drugs (79%). Parents reported immune-related conditions in cases (18%) and their nuclear, biological family (48%; 39% in biological mothers).

FUTURE PLANS

Future plans include increasing sample size, collecting longitudinal survey data, recruiting appropriate study controls and expanding the scope of the database, prioritising medical record data integration and creating a linked biorepository. Secondary data analyses will prioritise identifying subgroups by phenotypic traits, maternal health and disease characteristics.

Identification of ultra-rare genetic variants in pediatric acute onset neuropsychiatric syndrome (PANS) by exome and whole genome sequencing

Abrupt onset of severe neuropsychiatric symptoms including obsessive-compulsive disorder, tics, anxiety, mood swings, irritability, and restricted eating is described in children with Pediatric Acute-Onset Neuropsychiatric Syndrome (PANS). Symptom onset is often temporally associated with infections, suggesting an underlying autoimmune/autoinflammatory etiology, although direct evidence is often lacking. The pathological mechanisms are likely heterogeneous, but we hypothesize convergence on one or more biological pathways. Consequently, we conducted whole exome sequencing (WES) on a U.S. cohort of 386 cases, and whole genome sequencing (WGS) on ten cases from the European Union who were selected because of severe PANS. We focused on identifying potentially deleterious genetic variants that were de novo or ultra-rare (MAF) < 0.001. Candidate mutations were found in 11 genes (PPM1D, SGCE, PLCG2, NLRC4, CACNA1B, SHANK3, CHK2, GRIN2A, RAG1, GABRG2, and SYNGAP1) in 21 cases, which included two or more unrelated subjects with ultra-rare variants in four genes. These genes converge into two broad functional categories. One regulates peripheral immune responses and microglia (PPM1D, CHK2, NLRC4, RAG1, PLCG2). The other is expressed primarily at neuronal synapses (SHANK3, SYNGAP1, GRIN2A, GABRG2, CACNA1B, SGCE). Mutations in these neuronal genes are also described in autism spectrum disorder and myoclonus-dystonia. In fact, 12/21 cases developed PANS superimposed on a preexisting neurodevelopmental disorder. Genes in both categories are also highly expressed in the enteric nervous system and the choroid plexus. Thus, genetic variation in PANS candidate genes may function by disrupting peripheral and central immune functions, neurotransmission, and/or the blood-CSF/brain barriers following stressors such as infection.

Streptococcal Infection as a Major Historical Cause of Stuttering: Data, Mechanisms, and Current Importance

Stuttering is one of the most well-known speech disorders, but the underlying neurological mechanisms are debated. In addition to genetic factors, there are also major non-genetic contributions. It is here proposed that infection with group A beta-hemolytic streptococcus (GAS) was a major underlying cause of stuttering until the mid-1900s when penicillin was introduced in 1943. The main mechanism proposed is an autoimmune reaction from tonsillitis, targeting specific molecules, for example within the basal ganglia. It is here also proposed that GAS infections may have continued to cause stuttering to some extent, to the present date, though more rarely. If so, early diagnosis of such cases would be of importance. Childhood cases with sudden onset of stuttering after throat infection may be particularly important to assess for possible GAS infection. The support for this hypothesis primarily comes from three lines of argument. First, medical record data from the 1930s strongly indicates that there was one type of medical event in particular that preceded the onset of childhood stuttering with unexpected frequency: diseases related to GAS throat infections. In particular, this included tonsillitis and scarlet fever, but also rheumatic fever. Rheumatic fever is a childhood autoimmune sequela of GAS infection, which was a relatively widespread medical problem until the early 1960s. Second, available reports of changes of the childhood prevalence of stuttering indicate striking parallels between stuttering and the incidence of rheumatic fever, with: (1) decline from the early 1900s; (2) marked decline from the introduction of penicillin in the mid 1940s; and (3) reaching a more stable level in the 1960s. The correlations between the data for stuttering and rheumatic fever after the introduction of penicillin are very high, at about 0.95. Third, there are established biological mechanisms linking GAS tonsillitis to immunological effects on the brain. Also, a small number of more recent case reports have provided further support for the hypothesis linking stuttering to GAS infection. Overall, it is proposed that the available data provides strong evidence for the hypothesis that GAS infection was a major cause of stuttering until the mid-1900s, interacting with genetic predisposition.

Clinical Management of Pediatric Acute-Onset Neuropsychiatric Syndrome: Part III-Treatment and Prevention of Infections

Objectives: Pediatric acute-onset neuropsychiatric syndrome (PANS) and its subset, pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS), are emerging autoimmune encephalopathies of childhood. Management guidelines are needed. This article, from the PANS/PANDAS Consortium, presents a consensus management guideline for the infection components. Accompanying papers from the Consortium discuss psychiatric and immunomodulatory management. Methods: Literature was reviewed and integrated with the clinical experience of the authors to provide a set of practical guidelines. This article was submitted to all members of the PANS/PANDAS Consortium, and their additional comments were added. Results: The relationships between PANS and infections are reviewed. An approach to the retrospective diagnosis of group A streptococcal infection for an operational definition of PANDAS is proposed. An initial course of anti-streptococcal treatment is proposed for all newly diagnosed PANS cases. Chronic secondary antimicrobial prophylaxis is suggested for children with PANDAS who have severe neuropsychiatric symptoms or recurrent group A Streptococcus-associated exacerbations. Guidelines for children with non-streptococcal PANS include vigilance for streptococcal pharyngitis or dermatitis in the patient and close contacts. All patients with PANS or PANDAS should also be closely monitored for other intercurrent infections, including sinusitis and influenza. Intercurrent infections should be diagnosed and treated promptly according to current standard guidelines. A guideline for the assessment of infection at initial onset or during neuropsychiatric exacerbations is also presented. Standard immunizations and attention to vitamin D are encouraged. Data indicating limited utility of adenotonsillectomy and probiotics are presented. Conclusion: A working guideline for the management of infection issues in PANS and PANDAS, based on literature and expert opinion, is provided.

Pediatric acute-onset neuropsychiatric syndrome

Whether some instances of obsessive-compulsive disorder are secondary to infectious and/or autoimmune processes is still under scientific debate. The nosology has undergone an iterative process of criteria and acronyms from PITANDS to PANDAS to PANS (or CANS for neurology). This review focuses on the clinical presentation, assessment, proposed pathophysiology, and treatment of pediatric autoimmune neuropsychiatric disorders associated with streptococcus (PANDAS), and the newest iteration, pediatric acute-onset neuropsychiatric syndrome (PANS). Children who have these symptoms, which have become known as PANS, have been described by their parents as "changed children."

Lyme disease and pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS): an overview

Lyme disease (LD) is a complex, multisystemic illness. As the most common vector- borne disease in the United States, LD is caused by bacterial spirochete Borrelia burgdorferi sensu stricto, with potential coinfections from agents of anaplasmosis, babesiosis, and ehrlichiosis. Persistent symptoms and clinical signs reflect multiorgan involvement with episodes of active disease and periods of remission, not sparing the coveted central nervous system. The capability of microorganisms to cause and exacerbate various neuropsychiatric pathology is also seen in pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS), a recently described disorder attributed to bacterium Streptococcus pyogenes of group A beta-hemolytic streptococcus in which neurologic tics and obsessive-compulsive disorders are sequelae of the infection. In the current overview, LD and PANDAS are juxtaposed through a review of their respective infectious etiologies, clinical presentations, mechanisms of disease development, courses of illness, and treatment options. Future directions related to immunoneuropsychiatry are also discussed.