Summary Recent discoveries of ultra-rare protein truncating variants (PTVs) that confer substantially higher risk (effect sizes ≥2 up to ≈60) than common risk-variants discovered by GWAS, provides advantageous tools to investigate biological mechanisms in schizophrenia (SCZ). However, it is not known whether the PTVs are associated with similar phenotypic presentation as in idiopathic SCZ. To learn about the clinical presentation associated with the PTVs, we propose to study the longitudinal medical data of SCZ cases carrying these variants and compare it to individuals without these variants. This way we aim to elucidate the clinical commonalities between the idiopathic and rare genetic forms of schizophrenia. Recently, the Schizophrenia Exome Meta-Analysis Consortium (SCHEMA) has identified ultra-rare PTVs in 10 genes significantly associated with schizophrenia (Singh et al, Nature, 2022), and additional genes with FDR < 0.05 (total: 43 genes to date, FDR <0.05, unpublished). In addition, previous work has identified CNVs in several genomic loci with associated risk for SCZ (Marshall et al, Nature Genetics, 2017). To characterize phenotypic features associated with these ultra-rare variants among individuals with SCZ, we propose to longitudinally assess the medical history of individuals harboring deleterious variants in SCHEMA identified genes and known CNVs. We propose to do this by combining the largest schizophrenia study in Finland (the SUPER-Finland psychosis study (n=10,403 (all psychotic cases), n=5,519 (SCZ diagnosis)) with the largest schizophrenia study in Sweden (The Sweden Schizophrenia Study (n=4623 cases with WES data and ~6000 controls)). The combined dataset will provide increased power to identify phenotypic particularities in individuals with a PVT in certain genes. Both Finland and Sweden hold high quality medical health care registries with a long retrospective follow-up, unique to the Nordic countries, which we believe is key to investigate disease mechanisms in psychotic disorders. Significance: For the first time, loss-of-function variants in single genes have been confidently associated with schizophrenia by efforts from the Schizophrenia Exome Meta-Analysis Consortium (SCHEMA). Our study will apply these SCHEMA findings towards better understanding SCZ heterogeneity and will be the largest thus far, encompassing more than 10,000 individuals with schizophrenia with available sequencing data and longitudinal high-quality health care registry data. Together the Sweden Schizophrenia Study and the SUPER-Finland study can facilitate phenotypic characterization of these monogenic models for schizophrenia. The results hope to widen the understanding of psychotic disease, but also help to identify molecular targets for drug discovery.