Somatic Double Inactivation of NF1 Associated with NF1-Related Pectus Excavatum Deformity

Area of Science:

• Genetics
• Molecular Biology
• Developmental Biology

Background:

• Neurofibromatosis type 1 (NF1) is a genetic disorder causing diverse symptoms, including skeletal anomalies.
• Pectus excavatum (PE) is an increasingly recognized skeletal manifestation associated with NF1.

Purpose of the Study:

• To investigate the pathogenic mechanism of NF1-related pectus excavatum.
• To explore the role of somatic NF1 mutations in the development of chest deformities.

Main Methods:

• Next-generation sequencing (NGS) of affected cartilage.
• Exome sequencing of patient DNA.
• Western blot analysis to detect NF1 protein expression.

Main Results:

• A germline pathogenic NF1 variant and a somatic second hit frameshift NF1 variant were identified in the affected cartilage.
• Absence of wild-type NF1 protein confirmed in patient cartilage.
• Findings support somatic double inactivation (SDI) of NF1 in NF1-related PE.

Conclusions:

• Somatic double inactivation (SDI) of the NF1 gene is a key mechanism in the pathogenesis of NF1-related pectus excavatum.
• This finding expands the understanding of molecular mechanisms underlying NF1 skeletal manifestations.