De novo EDA mutations: Variable expression in two Egyptian families

Area of Science:

• Genetics and Molecular Biology
• Developmental Biology
• Human Disease Genetics

Background:

• Mutations in the EDA gene can cause overlapping phenotypes, including non-syndromic tooth agenesis (NTA) and hypohidrotic ectodermal dysplasia (HED).
• Investigating genetic variations in EDA and other candidate genes is crucial for understanding sporadic NTA and HED in affected individuals.

Observation:

• Two unrelated Egyptian male children with sporadic NTA and HED were analyzed.
• Direct sequencing of EDA, MSX1, PAX9, WNT10A, and EDAR genes was performed in the probands and their families.

Findings:

• A novel in-frame deletion in the EDA gene (c.663-680delTCCTCCTGGTCCTCAAGG, p.222-227delPPGPQG) was identified in a patient with NTA.
• A second EDA mutation (c.463C>T, p.Arg155Cys, rs132630312) was found in a patient with typical HED features.
• No pathogenic variants were detected in MSX1, PAX9, WNT10A, or EDAR genes, and the identified EDA mutations were absent in family members and controls.

Implications:

• These findings expand the known spectrum of EDA mutations associated with NTA and HED.
• The results support the hypothesis that X-linked HED and EDA-related NTA represent a spectrum of the same disease with varying severity.
• Understanding EDA mutations is vital for diagnosing and potentially managing these developmental disorders.