EGFR mutations cause a lethal syndrome of epithelial dysfunction with progeroid features

Area of Science:

• Molecular Biology
• Genetics
• Developmental Biology

Background:

• Epidermal growth factor receptor (EGFR) signaling is crucial for normal tissue development.
• Aberrant EGFR activation is implicated in oncogenic transformation.
• EGFR is a receptor tyrosine kinase mediating extracellular signals.

Purpose of the Study:

• To investigate the role of novel EGFR mutations in a severe congenital disorder.
• To elucidate the functional consequences of identified EGFR mutations on EGF signaling.
• To confirm the pathogenicity of EGFR mutations in inherited disease.

Main Methods:

• Genetic analysis to identify homozygous mutations in the EGFR gene (c.1283G>A, p.Gly428Asp).
• Functional assays using patient-derived fibroblasts to assess EGF-induced receptor phosphorylation and downstream signaling.
• In vitro studies on heterologously expressed EGFR extracellular domain to evaluate stability and EGF binding.
• Cellular senescence assays (β-galactosidase, telomere length) in patient-derived cells.

Main Results:

• Identified homozygous EGFR mutations (p.Gly428Asp) in two siblings with premature birth, skin/hair abnormalities, multisystem organ failure, and neonatal death.
• Mutated EGFR failed to phosphorylate upon EGF stimulation in patient fibroblasts, suppressing downstream signaling.
• The extracellular domain of mutated EGFR showed impaired stability and EGF binding.
• Patient cells exhibited accelerated senescence with shortened telomeres.

Conclusions:

• Homozygous mutations in the EGFR gene can cause a severe, lethal congenital disease.
• The identified EGFR mutations impair receptor stability, EGF binding, and downstream signaling, leading to developmental failure and early senescence.
• These findings confirm the critical role of functional EGFR in human development and underscore the pathogenicity of these specific EGFR mutations.