Trichothiodystrophy

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Trichothiodystrophy (TTD) is a rare genetic disorder characterized by brittle hair, intellectual disability, and a variety of other symptoms. The condition is named for the sulfur-deficient brittle hair that is a hallmark of the disorder. TTD is part of a group of disorders known as DNA repair disorders, which also includes xeroderma pigmentosum and Cockayne syndrome.

Signs and Symptoms

Individuals with trichothiodystrophy often exhibit a range of symptoms, which can vary widely in severity. Common features include:

• Brittle hair with a characteristic "tiger tail" banding pattern under polarized light microscopy
• Intellectual disability or developmental delay
• Short stature
• Ichthyosis (scaly skin)
• Photosensitivity
• Recurrent infections
• Premature aging

Genetics

Trichothiodystrophy is typically inherited in an autosomal recessive manner, meaning that an individual must inherit two copies of the defective gene, one from each parent, to be affected. Several genes have been implicated in TTD, including ERCC2, ERCC3, and GTF2H5, which are involved in the nucleotide excision repair pathway of DNA repair.

Diagnosis

Diagnosis of trichothiodystrophy is based on clinical features, hair analysis, and genetic testing. The characteristic brittle hair can be identified through microscopic examination, which reveals the "tiger tail" banding pattern. Genetic testing can confirm mutations in the genes associated with TTD.

Treatment

There is no cure for trichothiodystrophy, and treatment is primarily supportive and symptomatic. Management may include:

• Regular monitoring and treatment of infections
• Physical therapy and special education services for developmental delays
• Skin care for ichthyosis
• Sun protection for photosensitivity

Prognosis

The prognosis for individuals with trichothiodystrophy varies depending on the severity of symptoms. Some individuals may have a relatively mild form of the disorder, while others may experience significant health challenges and reduced life expectancy.

See Also

• DNA repair
• Xeroderma pigmentosum
• Cockayne syndrome
• Genetic disorder

External Links

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