PHF8 gene
The PHF8 gene plays a crucial role in gene regulation within brain cells, and its dysfunction is linked to intellectual disability and craniofacial abnormalities.
Normal Function
The PHF8 gene provides instructions for creating a protein found in the cell nucleus, particularly in developing brain cells. The PHF8 protein is a zinc finger protein that helps regulate gene expression through chromatin remodeling. Chromatin is the complex of DNA and proteins (histones) that packages DNA into chromosomes.
The PHF8 protein binds to chromatin and uses its Jumonji C (JmjC) domain to remove methyl groups from histones (demethylation). This process causes chromatin to become loosely packed, which generally turns genes "on" and increases their expression. This regulation is vital for normal brain development.
Health Conditions Related to Genetic Changes
X-linked intellectual disability, Siderius type
Mutations in the PHF8 gene cause X-linked intellectual disability, Siderius type, a condition affecting only males. Symptoms include:
- Mild to moderate intellectual disability
- Cleft lip
- Cleft palate
Most mutations result in an abnormally short protein that cannot enter the nucleus, or they impair the protein's ability to remove methyl groups from histones. This failure in chromatin remodeling disrupts the expression of genes necessary for intellectual function and the formation of skull structures, leading to the condition's characteristic features.
Genomic Location
The PHF8 gene is located on the X chromosome.