A Young Boy with Brittle Hair

Area of Science:

• Genetics
• Dermatology
• Medical Diagnostics

Background:

• Trichothiodystrophy (TTD) is a rare autosomal recessive disorder.
• It presents with diverse symptoms, including hair abnormalities and developmental delays.
• Mutations in DNA repair genes are implicated in TTD pathogenesis.

Observation:

• A 5-year-old boy with sparse, brittle hair, born to consanguineous parents, was evaluated.
• Standard trichoscopy and light microscopy showed broken hairs without specific shaft defects.
• A bedside technique using a polarized dermatoscope and mirror was employed for hair shaft transillumination.

Findings:

• The bedside technique revealed distinct bright and dark bands, the "tiger tail" sign.
• This sign is pathognomonic for Trichothiodystrophy.
• Polarizing microscopy confirmed the clinical diagnosis, validating the bedside method.

Implications:

• This study introduces a feasible bedside method for diagnosing TTD.
• The technique expands the clinical diagnostic toolkit for Trichothiodystrophy.
• Early and accessible diagnosis can potentially improve patient management and outcomes.