Characterising and predicting haploinsufficiency in the human genome

Area of Science:

• Genomics
• Human Genetics
• Computational Biology

Background:

• Haploinsufficiency (HI) is a key mechanism in dominant genetic diseases, with hundreds of HI genes identified.
• Understanding the distinction between haplosufficient (HS) and HI genes is crucial for interpreting genetic variations.

Purpose of the Study:

• To systematically identify haplosufficient (HS) genes in healthy individuals.
• To compare genomic, evolutionary, functional, and network properties of HS and HI genes.
• To develop a predictive model for identifying potential HI genes and assessing deletion pathogenicity.

Main Methods:

• Compiled a map of 1,079 HS genes from 8,458 healthy individuals based on copy number variation.
• Contrasted genomic, evolutionary, functional, and network features between HS and HI genes.
• Built a predictive model for haploinsufficiency probability and validated it using disease gene enrichment and mouse models.

Main Results:

• HI genes are typically longer, possess more conserved coding sequences and promoters, show higher early developmental expression, and greater tissue specificity than HS genes.
• HI genes exhibit more interaction partners and greater network proximity in human functional networks.
• The predictive model successfully identified genes implicated in dominant diseases and abnormal phenotypes in heterozygous knockout mice.

Conclusions:

• Distinct properties differentiate HI and HS genes, enabling the development of a robust predictive model for haploinsufficiency.
• Haploinsufficiency scores for deletions improve the discrimination between pathogenic and benign deletions.
• These findings aid in the clinical interpretation of loss-of-function variants and prioritize genes for further research.