Trichothiodystrophy
Trichothiodystrophy | |
---|---|
Other names | Amish brittle hair syndrome, BIDS syndrome, brittle hair–intellectual impairment–decreased fertility–short stature syndrome[1] |
This condition is inherited in an autosomal recessive manner.[1] | |
Specialty | Dermatology, medical genetics |
Trichothiodystrophy (TTD) is an
Presentation
Features of TTD can include photosensitivity, ichthyosis, brittle hair and nails, intellectual impairment, decreased fertility and short stature. A more subtle feature associated with this syndrome is a "tiger tail" banding pattern in hair shafts, seen in microscopy under polarized light.[3] The acronyms PIBIDS, IBIDS, BIDS and PBIDS give the initials of the words involved. BIDS syndrome, also called Amish brittle hair brain syndrome and hair-brain syndrome,[4] is an autosomal recessive[5] inherited disease. It is nonphotosensitive. BIDS is characterized by brittle hair, intellectual impairment, decreased fertility, and short stature.[6]: 501 There is a photosensitive syndrome, PBIDS.[7]
BIDS is associated with the gene
IBIDS syndrome is nonphotosensitive.Cause
The photosensitive form is referred to as PIBIDS, and is associated with
Photosensitive forms
All photosensitive TTD syndromes have defects in the nucleotide excision repair (NER) pathway, which is a vital DNA repair system that removes many kinds of DNA lesions. This defect is not present in the nonphotosensitive TTD's.[17] These type of defects can result in other rare autosomal recessive diseases like xeroderma pigmentosum and Cockayne syndrome.[18]
DNA repair
Currently, mutations in four genes are recognized as causing the TTD phenotype, namely TTDN1, XPB, XPD and TTDA.[19] Individuals with defects in XPB, XPD and TTDA are photosensitive, whereas those with a defect in TTDN1 are not. The three genes, XPB, XPD and TTDA, encode protein components of the multi-subunit transcription/repair factor IIH (TFIIH). This complex factor is an important decision maker in NER that opens the DNA double helix after damage is initially recognized. NER is a multi-step pathway that removes a variety of different DNA damages that alter normal base pairing, including both UV-induced damages and bulky chemical adducts. Features of premature aging often occur in individuals with mutational defects in genes specifying protein components of the NER pathway, including those with TTD[20] (see DNA damage theory of aging).
Diagnosis
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Treatment
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See also
- Skin lesion
- List of cutaneous conditions
References
- ^ a b "Trichothiodystrophy". Genetics Home Reference. Retrieved 19 February 2018.
- PMID 20687499.)
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: CS1 maint: multiple names: authors list (link - PMID 15692466.
- ^ Online Mendelian Inheritance in Man (OMIM): 234050
- PMID 984047.
- ^ ISBN 0-07-138076-0.
- ^ Hashimo S, and Egly JM. Trichothiodystrophy view from the molecular basis of DNA repair transcription factor TF11H.www.oxfordjournals.org/content/18/R2/R224
- PMID 15645389.
- PMID 5120162.
- ^ a b Online Mendelian Inheritance in Man (OMIM): 601675
- ISBN 978-1-4160-2999-1.
- ^ Hashimoto S, and Egly JM, www.oxfordjournals.org/content/18/R2/R224
- PMID 19931493.
- ISBN 978-0-7216-2921-6.
- S2CID 23534246.
- ^ Online Mendelian Inheritance in Man (OMIM): 616390
- ^ Hashimoto S, and Egly JM http://www.oxfordjournals.org/content/18/R2/R224[permanent dead link]
- S2CID 31063628.
- PMID 25016283.
- PMID 26287260.