NSD1 mutations generate a genome-wide DNA methylation signature

Area of Science:

• Epigenetics
• Genomics
• Developmental Biology

Background:

• Sotos syndrome (SS) is an overgrowth and intellectual disability disorder linked to mutations in the NSD1 gene, a histone methyltransferase.
• Epigenetic modifications are interdependent, suggesting NSD1 mutations may affect DNA methylation (DNAm) globally.
• Understanding these epigenetic changes is crucial for elucidating SS pathophysiology.

Purpose of the Study:

• To investigate the genome-wide impact of pathogenic NSD1 mutations on DNA methylation in Sotos syndrome.
• To identify a DNA methylation signature specific to SS that can differentiate it from controls and related disorders.
• To explore the functional implications of identified DNAm alterations in relation to SS phenotypes.

Main Methods:

• Genome-wide DNA methylation profiling of patients with Sotos syndrome and relevant control groups.
• Bioinformatic analysis to identify statistically significant DNA methylation patterns specific to NSD1 mutations.
• Validation of the identified DNA methylation signature in independent patient cohorts.

Main Results:

• A highly significant, genome-wide DNA methylation signature specific to NSD1 mutations (+/-) was identified in Sotos syndrome patients.
• This signature accurately differentiated SS from controls, benign NSD1 variants, and Weaver syndrome with 100% accuracy in validation studies.
• The identified DNAm alterations were associated with genes involved in cellular morphogenesis and neuronal differentiation.

Conclusions:

• Pathogenic NSD1 mutations induce genome-wide DNA methylation alterations in Sotos syndrome.
• The identified SS-specific DNA methylation signature offers a sensitive and specific biomarker for diagnosis.
• These findings advance the understanding of SS molecular mechanisms and pave the way for improved diagnostic tools.