Abstract: We report a patient with trichothiodystrophy associated with autism, mental retardation, and seizures. The diagnosis was based on the presence of brittle hair, with a marked decrease in sulfur-rich amino acid content, and characteristic features such as “tiger tail” under polarizing microscopy and trichoschisis under scanning electron microscopy. Macroscopic alterations were mostly observed in the frontal and occipital hair, with only microscopic abnormalities in the occipital hair. We consider this an unusual expression of this disease.