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The Journal of Investigative Dermatology Nov 1998Monilethrix is an inherited hair dystrophy in which affected, fragile, hairs have an unique beaded morphology. Ultrastructural studies suggest a defect in filament... (Review)
Review
Monilethrix is an inherited hair dystrophy in which affected, fragile, hairs have an unique beaded morphology. Ultrastructural studies suggest a defect in filament structure in the cortex of the hair, and the hard keratins of hair and nail are thus candidate genes. In several families with autosomal dominant monilethrix, the disorder has been linked to the type II keratin gene cluster at chromosome 12q13. Recently, causative mutations in the critical helix termination motif in the 2B domain of the human hair basic keratin 6 (hHb6) have been identified. We now report the results of sequencing this domain in 13 unrelated families or cases with monilethrix. Five of the 13 had the same mutation as previously found, a G to A transversion leading to a lysine for glutamic acid substitution (E413K) in the 2B domain (residue 117 of the 2B helix) of hHb6. The mutation was confirmed by a restriction fragment length polymorphism assay developed for this purpose, and, as this mutation is evidently a common cause of the syndrome, for use in screening other cases. In eight families or cases, however, including three in whom linkage data are consistent with a defect at the type II keratin locus, no mutation was found in this domain of hHb6.
Topics: Family Health; Hair Diseases; Humans; Keratins; Pedigree; Polymorphism, Restriction Fragment Length; Protein Structure, Tertiary
PubMed: 9804356
DOI: 10.1046/j.1523-1747.1998.00362.x -
International Journal of Trichology 2018Hair loss is a common and distressing clinical complaint in the dermatology clinics. Common causes of hair loss in children include alopecia areata, tinea capitis,...
INTRODUCTION
Hair loss is a common and distressing clinical complaint in the dermatology clinics. Common causes of hair loss in children include alopecia areata, tinea capitis, traction alopecia, and trichotillomania. Newly, trichoscopy allows differential diagnosis of hair loss in most cases and allows visualization of hair shafts and scalps without the need of removing hair.
OBJECTIVE
The main objective is to compare the different trichoscopic features of common causes of patchy hair in children loss including tinea capitis, alopecia areata, traction alopecia, and trichotillomania.
PATIENTS AND METHODS
This study included 134 patients, 63 patients with tinea capitis, 38 patients with alopecia areata, 18 patients with traction alopecia, and 15 patients with trichotillomania. The diagnostic tools for the diagnosis of hair loss problem included a detailed history, evaluation of the child's hair and scalp, fungal scrapping, and trichoscopy.
RESULTS
Tinea capitis was the most common, and the trichoscopic features were comma-shaped hairs, corkscrew hairs, short broken hairs, and interrupted hairs. While in alopecia areata patients, the most specific features were yellow dots and black dots, microexclamation mark, hair shafts with variable thickness, and vellus hairs, with uncommon features included: monilethrix, coiled, zigzag, and tulip hairs. Trichoscopy of trichotillomania showed hair with fraying of ends, breakage at different lengths, short and coiled hairs, and amorphous hair residues. The trichoscopic features of traction alopecia were similar to those of trichotillomania. However, flame hairs and coiled hairs were less common.
CONCLUSIONS
Trichoscopy is a noninvasive method of examining hair and scalp. It allows differential diagnosis of hair loss in most cases.
PubMed: 30386074
DOI: 10.4103/ijt.ijt_101_17 -
The Journal of Investigative Dermatology Oct 1999Monilethrix is an hereditary hair dystrophy recently shown to be due to mutations in the helix termination motif of two type II (basic) human hair keratin genes, hHb1...
Monilethrix is an hereditary hair dystrophy recently shown to be due to mutations in the helix termination motif of two type II (basic) human hair keratin genes, hHb1 and hHb6. It has been suggested that mutation in hHb1 produces a less severe phenotype. We have studied hair keratin genes and clinical features in 18 unrelated pedigrees of monilethrix from Germany, Scotland, Northern Ireland, and Portugal, in 13 of which mutations have not previously been identified. By examining the rod domains of hHb1, hHb3 and hHb6, we have identified mutations in nine of the new pedigrees. We again found the glutamine-lysine substitution (E413K) in the helix termination motif of hHb6 in two families, and in another, the corresponding E413K substitution in the hHb1 gene. In four families a similar substitution E402K was present in a nearby residue. In addition two novel mutations within the helix initiation motif of hHb6 were found in Scottish and Portuguese cases, in whom the same highly conserved asparagine residue N114 was mutated to histidine (N114H) or aspartic acid (N114D) residues, respectively. In four other monilethrix pedigrees mutations in these domains of hHb1, hHb3, and hHb6 were not found. The mutations identified predict a variety of possible structural consequences for the keratin molecule. A comparison of clinical features and severity between cases with hHb1 and hHb6 mutations does not suggest distinct effects on phenotype, with the possible exception of nail dystrophy, commoner with hHb1 defects. Other factors are required to explain the marked variation in clinical severity within and between cases.
Topics: Amino Acid Sequence; Codon; Female; Genotype; Hair Diseases; Humans; Keratins; Male; Molecular Sequence Data; Mutation; Phenotype; Polymorphism, Restriction Fragment Length; Protein Structure, Secondary
PubMed: 10504448
DOI: 10.1046/j.1523-1747.1999.00722.x -
The Journal of Investigative Dermatology May 1965
Topics: Arginine; Citrulline; Hair; Histocytochemistry; Humans; Keratins; Metabolic Diseases; Monilethrix
PubMed: 14290311
DOI: No ID Found -
Ugeskrift For Laeger Sep 2017Monilethrix is a rare genodermatosis with high penetrance and variable expressivity. This is a case report of a Danish family with varying phenotypical presentations....
Monilethrix is a rare genodermatosis with high penetrance and variable expressivity. This is a case report of a Danish family with varying phenotypical presentations. The family members were diagnosed using dermatoscopy and microscopy, which were subsequently supported by gene sequence analysis. No cure of monilethrix exists, but a single case report shows promising results using low dosage of oral minoxidil. Reducing hair dressing trauma to diminish weathering remains the best prophylaxis.
Topics: Adult; Child; Child, Preschool; Family; Female; Genetic Testing; Humans; Male; Monilethrix
PubMed: 28918778
DOI: No ID Found -
Journal of Dermatological Case Reports Jul 2008Diagnosis of hair shaft abnormalities is based on light microscopic examination of more than 50 plucked hairs. The aim of this study was to verify whether hair shaft...
BACKGROUND
Diagnosis of hair shaft abnormalities is based on light microscopic examination of more than 50 plucked hairs. The aim of this study was to verify whether hair shaft abnormalities may be visualized by trichoscopy (hair and scalp videodermoscopy) and to analyze trichoscopic features of common genetic hair shaft dysplasias.
METHOD
Patients with known genetic hair shaft disorders were included into the study. Trichoscopy was performed with the use of Fotofinder II videodermoscope. Images performed at 20-fold and 70-fold magnification were analysed. In selected cases 160-fold magnification was used for better visualization of hair shafts.
RESULTS
Our results show that characteristic light microscopy features of Netherton syndrome, monilethrix, woolly hair syndrome, pili torti, pili annulati and trichothiodystrophy may be visualized by trichoscopy.
CONCLUSION
Genetic hair shaft abnormalities may be diagnosed by trichoscopy in a single diagnostic session without the need of plucking or cutting them for diagnostic purposes.
PubMed: 21886705
DOI: 10.3315/jdcr.2008.1009 -
The Journal of Investigative Dermatology Dec 1996Monilethrix is a rare inherited defect of the hair shaft resulting in hair fragility and dystrophic alopecia. In contrast to recent reports mapping monilethrix to the...
Monilethrix is a rare inherited defect of the hair shaft resulting in hair fragility and dystrophic alopecia. In contrast to recent reports mapping monilethrix to the type II epithelial and trichocyte keratin gene cluster on 12q13, we strongly excluded these candidate genes in another family with autosomal dominant monilethrix. Moreover, there was no evidence for linkage of the disease to the keratin gene cluster on chromosome 17q12-q21, thus excluding defects in all known trichocyte and epithelial keratins as the cause of monilethrix in this family. Likewise, several other genes known to play an important role in hair shaft formation (trichohyalin and involucrin, ultra-high sulfur matrix proteins, and transglutaminases 1, 2, and 3) did not provide any evidence for linkage. Our results indicate genetic heterogeneity in monilethrix and suggest that aberrations in at least one other gene result in a similar phenotype.
Topics: Age Factors; Chromosome Mapping; Chromosomes, Human, Pair 12; Female; Hair; Humans; Keratins; Male; Pedigree; Phenotype; Transglutaminases
PubMed: 8941666
DOI: 10.1111/1523-1747.ep12330568 -
Indian Dermatology Online Journal 2020Monilethrix is a rare hereditary disorder affecting hair resulting in hair fragility and alopecia. We report three patients of monilethrix who presented with complaints...
Monilethrix is a rare hereditary disorder affecting hair resulting in hair fragility and alopecia. We report three patients of monilethrix who presented with complaints of sparse and brittle hair from early childhood. All three patients had multiple discrete hyperkeratotic papules over the scalp. Dermoscopy revealed beaded appearance of hair with the presence of elliptical nodes and intermittent constrictions on the hair shafts as well as broken hairs, which were confirmed with routine microscopic examination of hair. Dermoscopy helps in easier and faster diagnosis of monilethrix.
PubMed: 32055512
DOI: 10.4103/idoj.IDOJ_93_19 -
Journal of Visualized Experiments : JoVE Mar 2011The homeostasis of all self-renewing tissues is dependent on adult stem cells. As undifferentiated stem cells undergo asymmetric divisions, they generate daughter cells...
The homeostasis of all self-renewing tissues is dependent on adult stem cells. As undifferentiated stem cells undergo asymmetric divisions, they generate daughter cells that retain the stem cell phenotype and transit-amplifying cells (TA cells) that migrate from the stem cell niche, undergo rapid proliferation and terminally differentiate to repopulate the tissue. Epithelial stem cells have been identified in the epidermis, hair follicle, and intestine as cells with a high in vitro proliferative potential and as slow-cycling label-retaining cells in vivo (1-3). Adult, tissue-specific stem cells are responsible for the regeneration of the tissues in which they reside during normal physiologic turnover as well as during times of stress (4-5). Moreover, stem cells are generally considered to be multi-potent, possessing the capacity to give rise to multiple cell types within the tissue (6). For example, rodent hair follicle stem cells can generate epidermis, sebaceous glands, and hair follicles (7-9). We have shown that stem cells from the human hair follicle bulge region exhibit multi-potentiality (10). Stem cells have become a valuable tool in biomedical research, due to their utility as an in vitro system for studying developmental biology, differentiation, tumorigenesis and for their possible therapeutic utility. It is likely that adult epithelial stem cells will be useful in the treatment of diseases such as ectodermal dysplasias, monilethrix, Netherton syndrome, Menkes disease, hereditary epidermolysis bullosa and alopecias (11-13). Additionally, other skin problems such as burn wounds, chronic wounds and ulcers will benefit from stem cell related therapies (14,15). Given the potential for reprogramming of adult cells into a pluripotent state (iPS cells)(16,17), the readily accessible and expandable adult stem cells in human skin may provide a valuable source of cells for induction and downstream therapy for a wide range of disease including diabetes and Parkinson's disease.
Topics: 3T3 Cells; Adult; Adult Stem Cells; Animals; Cell Culture Techniques; Epithelial Cells; Humans; Mice; Skin
PubMed: 21490579
DOI: 10.3791/2561 -
JAAD Case Reports May 2016
PubMed: 27284572
DOI: 10.1016/j.jdcr.2016.02.011