Genomic Variant Correlation Analysis with Complex Joins

Design a PostgreSQL database schema to track genetic variants across multiple research studies, integrating data from whole genome sequencing, RNA-seq, and clinical outcomes. Create a complex query that can correlate variant frequencies with specific phenotypic expressions, accounting for population stratification and statistical significance. The solution must handle nested JSON data from sequencing results, support efficient indexing for large-scale genomic datasets, and implement row-level security to protect patient privacy.