Undifferentiated psychosis or schizophrenia associated with vermis-predominant cerebellar hypoplasia.

Schizophrenia (SCZ) is a well-studied neuropsychiatric condition that has been shown to have a high degree of genetic heritability. Still, little data on the specific genetic risk variants associated with the disease exists. Classification of the SCZ phenotype into SCZ-related endophenotypes is a promising methodology to parse out and elucidate the specific genetic risk variants for each. Here, we present a series of 17 previously reported individuals and a new proband with similar SCZ-related neuropsychiatric characteristics and shared brain imaging findings. Unsurprisingly, these individuals shared classic psychiatric features of SCZ. Interestingly, we also identified shared neuropsychiatric features in this series of individuals that had not been highlighted previously. A consistently decreased IQ, memory impairment, sleep and speech disturbances, and attention deficits were commonly reported findings. The brain imaging findings among these individuals also consistently showed posterior vermis predominant cerebellar hypoplasia (CBLH-V). Most individuals' diagnoses were initially described as Dandy-Walker malformation; however, our independent review of imaging suggests a more consistent pattern of posterior vermis predominant cerebellar hypoplasia rather than true Dandy-Walker malformation. While the specific genetic risk variants for this endophenotype are yet to be described, the aim of this paper is to present the shared neuropsychiatric features and consistent, symmetrical brain image findings which suggest that this subset of individuals comprises an endophenotype of SCZ with a high genetic solve rate.

The Triad of Childhood-Onset Schizophrenia, Autism Spectrum Disorder, and Catatonia: A Case Report.

Childhood-onset schizophrenia (COS) is a rare and severe form of schizophrenia with an estimated prevalence of 1/10,000. Schizophrenia and Autism spectrum disorder (ASD) have shared phenotypic features and shared genetic etiology. There is growing research surrounding the co-occurrence of psychomotor syndromes like catatonia with neurodevelopmental disorders like ASD or psychiatric disorders like schizophrenia. In 2013, Shorter and Wachtel described a phenomenon of the 'Iron Triangle' where COS, ASD, and catatonia often co-occur. The Iron Triangle theory is based on observation of historical case literature, which showed that all three diagnoses in the Iron Triangle were routinely assigned to children and adolescents. The pattern of this "Iron Triangle" suggests there may be a single underlying pathology resulting in a unique mixed form of catatonia, autism, and psychosis. We describe the case of a boy with sequential development of COS, ASD, and catatonia who also has syndromic facial and musculoskeletal features. This case highlights overlapping diagnostic features of these three disorders and can help us better understand how "hidden" features of catatonia may occur in patients with COS or ASD but go unrecognized, because they are grouped as features under autism/schizophrenia rather than a distinct diagnosis of catatonia. Further study is warranted to elucidate if this phenotypic pattern constitutes a new single diagnosis that is not well understood, an endophenotype of schizophrenia, or if this is the result of phenomenological overlap between catatonia, ASD, and COS.