Paralog Studies Augment Gene Discovery: DDX and DHX Genes

Area of Science:

• Genetics
• Molecular Biology
• Neuroscience

Background:

• Paralogous genes with known disease associations are more likely to be implicated in human diseases.
• DHX30 and DDX3X pathogenic variants are known causes of neurodevelopmental disorders.
• The DExD/H-box RNA helicase superfamily plays crucial roles in cellular processes.

Purpose of the Study:

• To investigate the role of variants in DExD/H-box RNA helicase genes in neurodevelopmental disorders.
• To identify novel genetic causes for developmental delay and/or intellectual disability.
• To explore the spectrum of phenotypes associated with these genetic variants.

Main Methods:

• Exome sequencing was used to identify variants in affected individuals.
• Bioinformatic tools were employed to predict the pathogenicity of identified variants.
• Clinical data from 15 unrelated individuals with neurodevelopmental disorders were analyzed.

Main Results:

• Fifteen unrelated individuals with developmental delay and/or intellectual disability were found to have damaging variants in DExD/H-box RNA helicase genes.
• Variants in DHX37, DHX16, DDX54, and DHX34 were identified in these individuals.
• Phenotypes included central nervous system dysfunction, vertebral anomalies, dysmorphic features, and other organ system involvement.

Conclusions:

• DExD/H-box helicases are implicated in both dominant and recessive neurodevelopmental disorders.
• These findings expand the spectrum of genes associated with developmental delay and intellectual disability.
• The study highlights the genetic heterogeneity underlying neurodevelopmental phenotypes.