Hierarchical Genomic Analysis of Susceptibility to Schizophrenia in Sudanese multi-case families

Background

Schizophrenia, with its diverse and complex presentation, is a prime candidate for genetic investigation. Its heritability in both familial and sporadic cases, clinical overlap with other psychiatric conditions, and individual variations in response to treatment contribute to its complexity. Numerous genes and associated biochemical pathways show significant differences at the population, familial, and individual levels. Additionally, schizophrenia may represent an evolutionary trade-off for human brain development, creativity, and intellectual performance.

Material and Methods

This case pseudo-control study analyzed the whole genomes/exomes of seven Sudanese families with multiple siblings affected by schizophrenia. We examined shared variants among family members, including both cases and controls, and unique variants shared between patients but not controls. These variants were filtered based on their impact on protein function, expression levels, allele frequencies, ACMG classification for rare variants, and disease associations. Networks were created to identify central genes and common biological pathways.

Results and Discussion

The examination of this complex disorder in Sudanese families revealed numerous variants, both common and rare, showing differences between families and between our population and those reported in the literature. This highlights the challenge of accounting for the known heritability of the disease. Our hierarchical approach demonstrates that schizophrenia’s etiology involves the cumulative effect of various interacting variants in an ascending order of influence. Common variants are shared among all samples, while rare variants are shared among two or three families, most of which are associated with schizophrenia.

In Conclusion

The significance lies not merely in the number of detected variants but in understanding their interactive roles, step by step, to reveal the complete picture of the disease’s phenotype.