Related Experiment Videos
Trichothiodystrophy: ultrastructural studies of two patients
S Calvieri1, A Rossi, B Amorosi
1Department of Dermatology, University of Rome La Sapienza, Italy.
Insights
Trichothiodystrophy (TTD) in two girls revealed characteristic hair abnormalities and reduced cystine levels. Skin biopsies showed unique cellular changes, suggesting a keratin synthesis disorder in TTD patients.
Area of Science:
- Dermatology
- Genetics
- Biochemistry
Background:
- Trichothiodystrophy (TTD) is a rare genetic disorder characterized by brittle hair with reduced sulfur content.
- Previous studies indicate TTD affects multiple organs, including skin and hair.
Observation:
- Two pediatric patients, aged 18 months and 8 years, presented with TTD.
- Hair examination revealed characteristic bright and dark bands under polarized light.
- Amino acid analysis showed significantly reduced cystine levels in the hair of both patients.
Findings:
- Both patients exhibited distinct skin lesions: diffuse follicular keratosis and ichthyosiform dermatitis.
- Electron microscopy of skin biopsies revealed perinuclear vacuoles in keratinocytes and abnormal tonofilament bundles.
- These ultrastructural findings suggest a generalized defect in sulfur-containing proteins, impacting keratin synthesis.
Implications:
- The observed skin and hair abnormalities in TTD patients point to a potential disturbance in keratin synthesis.
- Ultrastructural skin findings may serve as a diagnostic marker for ichthyotic skin in TTD.
- Further research into sulfur-containing protein abnormalities in TTD is warranted.
Abstract:
An 18-month-old and an 8-year-old girl had trichothiodystrophy (TTD). Microscopic observation of the hair under polarized light showed typical alternation of bright and dark bands; amino acid analysis of the hair demonstrated a marked reduction of cystine levels. Both patients had skin lesions consisting in the older child of diffuse follicular keratosis since birth, and in the younger of an ichthyosiform dermatitis on the lower legs that appeared at age 4 months. Ultrastructural studies of the skin showed striking similarities in both cases: perinuclear vacuoles with a unit membrane in the keratinocytes, and dispersed, irregularly arranged bundles of tonofilaments particularly at the desmosome junction. The origin of the vacuoles is unknown; the abnormalities of the tonofilaments could be explained on the basis of a generalized abnormality in sulfur-containing proteins, reflecting a disturbance in the synthesis of keratins. These electron microscopy findings could be considered as a peculiar feature of ichthyotic skin in patients with TTD.