Mechanical anisotropy of hair affected by genetic diseases highlights structural information related to differential crosslinking in keratins.

Previous work with Atomic Force Microscope (AFM) nanoindentation, on longitudinal and cross-sections of the human hair fibre, allowed for the derivation of a model for the mechanical behaviour of human hair, called the Anisotropic Index. Expanding that research further, and by applying this model, the nanomechanical behaviour of hairs from patients with the disease Trichothiodystrophy (TTD) has been examined and structural insights, gained from combining the AFM results with Differential Scanning Calorimetry (DSC) experiments and tensile measurements, suggests that TTD-affected hairs have a relatively increased amount of Keratin Intermediate Filaments, contained in compartments of differing crosslinking extent. The associated calculations of axial and transverse Young's Moduli deliver values in good agreement with the measured fibre mechanics. Furthermore, comparing these findings with the results previously obtained from the study of hairs from patients with the disease Monilethrix, it is shown that the Anisotropic Index correlates well with the known deficiencies in both hair types obtained from such patients and allows for discerning between the Control hair and from those affected by the two diseases. AFM nanoindentation along and across the fibre axis and the Anisotropic Index thus appear to reveal structural details of hair not otherwise acquirable, whilst DSC may offer a quick and simple method for distinguishing between different severities of TTD.

Gene detection in a family with monilethrix and treatment with 5% topical minoxidil.

OBJECTIVE: To determine the causative gene mutation in a family with monilethrix and observe the therapeutic effect of 5% topical minoxidil. METHOD: Clinical data from a family with monilethrix were collected. Peripheral blood samples were taken from the proband, the parents, and 100 unrelated healthy controls. Genomic DNA was extracted. The genetic variation sites were screened with exome sequencing and verified by Sanger sequencing. The proband was treated with 5% topical minoxidil (1 mL twice daily). Hair quality was examined by dermoscopy before and after treatment. RESULTS: The proband and her father have the heterozygous missense variant c.1204G > A (p.E402K) in exon 7 of the KRT86 gene. However, the mutation was not found in the mother and healthy controls. The proband was treated with 5% topical minoxidil. Hair density and hair shaft quality improved significantly after 6 months of treatment. No adverse events occurred during treatment. CONCLUSION: This study shows that p.E402K is a mutation "hot spot" in patients with autosomal dominant monilethrix in China. Treatment with 5% topical minoxidil, is safe and effective.

Autosomal recessive monilethrix: Novel variants of the DSG4 gene in three Chinese families.

BACKGROUND: Monilethrix is a rare hereditary hair loss disorder characterized by hair fragility and beaded hair shaft alterations. Monilethrix is classically inherited in an autosomal dominant (AD) fashion caused by variants in the hair keratin genes KRT81, KRT83, or KRT86. Interestingly, an autosomal recessive (AR) form of monilethrix with variants in DSG4 gene has also been reported in recent years. OBJECTIVE: To identify causative variants in Chinese patients with autosomal recessive (AR) form of monilethrix. METHODS: Three families with AR form of monilethrix were observed and sequence variant analysis of DSG4 was performed by polymerase chain reaction (PCR), quantitative real-time PCR, and DNA sequencing. RESULTS: All the patients had sparse, fragile hair involving the scalp, eyebrows, and eyelashes with keratotic follicular papules and pruritus since birth. Atypical-beaded hairs and broken hair shaft fragments were identified in all the patients under dermoscopy. Heterozygous variants c.837del and c. 2389C > T, a homozygous splice site variant c.2355 + 1G > A, and a homozygous 48,644 bp large deletion variant g.31381440_31430084del in the DSG4 gene were identified and verified in the families. CONCLUSION: This report provided further evidence for the phenotypic spectrum and clinical features of, and the expanded variant database of AR form of monilethrix.

Update of recent findings in genetic hair disorders.

Genetic hair disorders, although unusual, are not very rare, and dermatologists often have opportunities to see patients. Significant advances in molecular genetics have led to identifying many causative genes for genetic hair disorders, including the recently identified causative genes, such as LSS and C3ORF52. Many patients have been detected with autosomal recessive woolly hair/hypotrichosis in the Japanese population caused by founder mutations in the LIPH gene. Additionally, many patients with genetic hair disorders caused by other genes have been reported in East Asia including Japan. Understanding genetic hair disorders is essential for dermatologists, and the findings obtained from analyzing these diseases will contribute to revealing the mechanisms of hair follicle morphogenesis and development in humans.

Moniletrix of the scalp from almost normal aspect to total alopecia: variable intrafamilial expressiveness

Abstract Monilethrix is a rare defect of the hair shaft, with most cases showing an autosomal dominant pattern of inheritance and variable clinical expression. It is characterized by hypotrichosis secondary to hair fragility. The diagnosis is made through trichoscopy, detecting typical findings such as periodic narrowing at regular intervals, giving the hair the appearance of beads in a rosary. This article reports the case of six members of a family diagnosed with monilethrix with alopecia of varying degrees.

Moniletrix of the scalp from almost normal aspect to total alopecia: variable intrafamilial expressiveness.

Monilethrix is a rare defect of the hair shaft, with most cases showing an autosomal dominant pattern of inheritance and variable clinical expression. It is characterized by hypotrichosis secondary to hair fragility. The diagnosis is made through trichoscopy, detecting typical findings such as periodic narrowing at regular intervals, giving the hair the appearance of beads in a rosary. This article reports the case of six members of a family diagnosed with monilethrix with alopecia of varying degrees.

Nanomechanical properties of Monilethrix affected hair are independent of phenotype.

Utilising the AFM nanoindentation technique for the study of hair cross- and longitudinal sections, the mechanical anisotropy of human hair fibres affected by a rare congenital condition, Monilethrix, has been investigated for the first time. Supported by X-ray microdiffraction data, and applying a model based on an ideal composite material consisting of rods (KIFs) and matrix (KAPs) to Monilethrix affected fibres, it has been shown that the results could be grouped into clearly different classes, namely: almost isotropic behaviour for Monilethrix affected hairs and anisotropic behaviour for Control hair. Moreover, AFM nanoindentation of hair cross sections has demonstrated, also for the first time that hairs affected by Monilethrix have a continuous, and not periodic, weakness within the cortex. This has been attributed to disruptions in the KIF-KIF, KIF-intermacrofibrillar matrix or KIF-desmosome complexes within the hair shaft, as suggested by X-ray microdiffraction examination. Hairs from a patient exhibiting no obvious phenotype exhibited similar mechanical weakness despite the otherwise normal visual appearance of the fibre. This further supports a hypothesis that the beaded appearance of Monilethrix hair is a secondary factor, unrelated to the inherent structural weakness.

Monilethrix: A Report of Three Cases in Children Confirmed with Dermoscopy.

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.

Mutation analysis of the type Ⅱ hair keratin gene in a family of Han nationality with monilethrix / 中华皮肤科杂志

Objective To detect mutations of the type Ⅱ human basic hair keratin (hHb) gene in a family of Han nationality with monilethrix.Methods Clinical data were collected from a family of Han nationality with monilethrix.Dermoscopy was performed to observe hairs of the family members,and light microscopy and scanning electron microscopy (SEM) were conducted to investigate the features of lesional hairs.Blood samples were obtained from the proband,other family members and 100 healthy controls,and DNA was extracted from these blood samples.Polymerase chain reaction (PCR) was performed to amplify the exons 1 and 7 of the hHb1,hHb3 and hHb6 genes,and DNA sequencing results were compared with their sequences in the GenBank database.Results The proband was an 8-year-old girl,whose head hairs had become fragile and easy to pull out since 2 months after birth.Skin examination showed diffuse sparsehairs,most of which were 2-cm-long broken hairs with abnormal appearance.Moniliform hairs were scattered all over the head,especially on the occipital region,and follicular keratotic papules were observed on the back of the neck.The proband was diagnosed with monilethrix.There were a total of 15 members in the 3-generation family,and 4 were diagnosed with monilethrix.The hair shafts of the 4 patients all showed typical moniliform structures.After 9-month consecutive treatment with topical minoxidil 2％ solution,the hairs of the proband turned longer and denser.A heterozygous mutation c.1237G＞A (p.E413K) was identified in the exon 7 of the hHb6 gene in the 4 patients,but not in the other family members or 100 healthy controls.Conclusion The E413K mutation of the hHb6 gene was firstly found in the patients in a Chinese Han family with monilethrix,which may be responsible for moniliform hairs.

Desmoglein 4 gene mutation analysis in a pedigree with autosomal recessive hereditary monilethrix / 中华皮肤科杂志

A 3-year-old female proband presented with patchy follicular keratotic papules on the hairless scalp after birth. At about the age of 2 years, sparse hairs of non-uniform thickness began to grow, but they fell out intermittently and were broken easily. Some eyebrows and eyelashes of different lengths fell out or were broken. Physical examination revealed good condition of nutrition, normal height, weight and intelligence, with no obvious abnormalities in other systems. Skin examination showed sparse and broken hairs with follicular keratotic papules on the vertex and occiput. Teeth, nails, toenails and sweat glands were normal. Dermoscopy, optical microscopy and scanning electron microscopy all showed that affected hairs gave a beaded appearance. Gene sequencing showed that the proband carried heterozygous deletions of exons 2-16 in the desmoglein 4 (DSG4) gene, and a heterozygous mutation c.574T>C (p.S192p) (NM-177986) in the DSG4 gene, which were inherited from her father and mother respectively. None of the above mutations in the DSG4 gene were found in 100 healthy controls. According to the gene sequencing results and clinical phenotype, the patient was finally diagnosed with autosomal recessive hereditary monilethrix, and the c.574T>C mutation and heterozygous deletions of exons 2-16 of the DSG4 gene may contribute to autosomal recessive hereditary monilethrix in the child.

Desmoglein 4 gene mutation analysis in a pedigree with autosomal recessive hereditary monilethrix / 中华皮肤科杂志

A 3-year-old female proband presented with patchy follicular keratotic papules on the hairless scalp after birth.At about the age of 2 years,sparse hairs of non-uniform thickness began to grow,but they fell out intermittently and were broken easily.Some eyebrows and eyelashes of different lengths fell out or were broken.Physical examination revealed good condition of nutrition,normal height,weight and intelligence,with no obvious abnormalities in other systems.Skin examination showed sparse and broken hairs with follicular keratotic papules on the vertex and occiput.Teeth,nails,toenails and sweat glands were normal.Dermoscopy,optical microscopy and scanning electron microscopy all showed that affected hairs gave a beaded appearance.Gene sequencing showed that the proband carried heterozygous deletions of exons 2-16 in the desmoglein 4 (DSG4) gene,and a heterozygous mutation c.574T＞C(p.S192p)(NM-177986) in the DSG4 gene,which were inherited from her father and mother respectively.None of theabove mutations in the DSG4 gene were found in 100 healthy controls.According to the gene sequencing results and clinical phenotype,the patient was finally diagnosed with autosomal recessive hereditary monilethrix,and the c.574T ＞ C mutation and heterozygous deletions of exons 2-16 of the DSG4 gene may contribute to autosomal recessive hereditary monilethrix in the child.

Description of clinical aspects and microscopy of the hair shaft of a carrier of familial monilethrix / Descrição dos aspectos clínicos e da microscopia da haste capilar de um portador de monilétrix familiar

ABSTRACT Monilethrix is a genetic condition that affects the hair shaft. We describe a family with this disease, focusing on its clinical aspects and microscopic hair characteristics. The patient was a 10-year-old female with history of hypotrichosis. In addition to diffuse alopecia, there was brittle hair, with ruptures in the hair shaft at different levels. The hair had a nodular appearance at naked eye. Other family members had the same symptoms, what indicates an autosomal dominant pattern of inheritance. Microscopic analysis revealed capillary fibers with areas of elliptical nodular appearance interspersed with regions of dystrophic constriction.

RESUMO A monilétrix é uma condição genética que acomete a haste capilar. Descrevemos uma família com essa doença, enfocando seus aspectos clínicos e as características microscópicas do cabelo. A paciente era do sexo feminino, 10 anos de idade, e apresentava história de hipotricose. Além da alopecia difusa, notava-se um cabelo quebradiço, com rupturas na haste capilar em diferentes níveis. Os cabelos possuíam um aspecto nodular a olho nu. Outros membros da família apresentavam os mesmos sintomas, o que indica um padrão de herança autossômica dominante. A análise microscópica revelou fibras capilares com áreas de aparência nodular elíptica, intercaladas por regiões de constrição distrófica.

Journey toward unraveling the molecular basis of hereditary hair disorders.

Recent advances in molecular genetics have led to the identification of many genes expressed in hair follicle (HF), while the precise roles of these genes in the HF have not completely been disclosed. Using the methods of forward genetics, we and others have recently identified a series of genes responsible for hereditary hair disorders in humans, including monilethrix, woolly hair, and various ectodermal dysplasia syndromes. Furthermore, expression and functional analyzes have gradually revealed that these genes are directly or indirectly related with each other. As such, the journey toward unraveling the molecular basis of hereditary hair disorders will contribute to better understanding of the complex mechanisms for HF morphogenesis and development in humans.

Monilethrix with holt-oram syndrome: case report of a rare association.

Congenital hypotrichosis may be due to a number of causes and may have multiple systemic associations. A child born of second-degree consanguineous marriage was found to have monilethrix as the cause of congenital hypotrichosis. A detailed systemic evaluation in the child revealed atrial septal defect and a hypoplastic right thumb leading to a diagnosis of coexisting Holt-Oram syndrome.

Novel KRT83 and KRT86 mutations associated with monilethrix.

Monilethrix is an autosomal dominant hair disorder caused by mutations in the hard keratins KRT81, KRT83 and KRT86. The affected hairs are fragile and break easily, leading to scarring alopecia. Follicular hyperkeratosis in the neck and on extensor sides of extremities is a frequently associated finding. The disorder is rare, but probably underreported because its manifestations may be mild. Mutations in KRT81 and KRT86 are the most common. Here, we report new cases from Venezuela, the Netherlands, Belgium and France. The Venezuelan kindred is special for having patients with digenic novel nucleotide changes, a KRT86 mutation associated with monilethrix and a KRT81 variant of unknown clinical significance. In the French and Dutch patients, we found novel KRT86 and KRT83 mutations. Our findings expand the mutational spectrum associated with monilethrix.