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The what, why and how of curly hair: a review.

ABSTRACT: An attempt to understand and explain a peculiarity that was observed for curly fibres during experimentation revealed disparate literature reporting on several key issues. The phenotypical nature of curly fibres is only accurately understood within the larger scope of hair fibres, which are highly complex biological structures. A brief literature search produced thousands of research items. Besides the large amount of information on the topic, there was also great variability in research focus. From our review, it appeared that the complexity of hair biology, combined with the variety of research subtopics, often results in uncertainty when relating different aspects of investigation. During the literature investigation, we systematically categorized elements of curly hair research into three basic topics: essentially asking why fibres curl, what the curly fibre looks like and how the curly fibre behaves. These categories were subsequently formalized into a curvature fibre model that is composed of successive but distinctive tiers comprising the elements in curly hair research. The purpose of this paper is twofold: namely to present (i) a literature review that explores the different aspects of curly human scalp hair and (ii) the curvature fibre model as a systemized approach to investigating curly hair.

SUBMITTER: Cloete E

PROVIDER: S-EPMC6894537 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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The what, why and how of curly hair: a review.

Cloete Elsabe E Khumalo Nonhlanhla P NP Ngoepe Malebogo N MN

Proceedings. Mathematical, physical, and engineering sciences 20191120 2231

An attempt to understand and explain a peculiarity that was observed for curly fibres during experimentation revealed disparate literature reporting on several key issues. The phenotypical nature of curly fibres is only accurately understood within the larger scope of hair fibres, which are highly complex biological structures. A brief literature search produced thousands of research items. Besides the large amount of information on the topic, there was also great variability in research focus. ...[more]

PMID: 31824224

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Project description:Hair types have been under strong targeted selection in domestic animals for their impact on skin protection, thermoregulation and exterior morphology, and subsequent economic importance. In pigs, a very special hair phenotype was observed in Mangalitza, who expresses a thick coat of curly bristles and downy hair. Two breed-specific missense variants in TRPM2 and CYP4F3 were suggested to be associated with the Mangalitza pig's hair shape due to their role in hair follicle morphogenesis reported for human and mice. However, the mechanism behind this expression of a curly hair type is still unclear and needs to be explored. In our study, hair shafts were measured and investigated for the curvature of the hair in Mangalitza and crossbreeds in comparison to straight-coated pigs. For molecular studies, hair roots underwent RNA sequencing for a differential gene expression analysis using DESeq2. The output matrix of normalized counts was then used to construct weighted gene co-expression networks. The resulting hair root gene expression profiles highlighted 454 genes to be significantly differentially expressed for initiation of curly hair phenotype in newborn Mangalitza piglets versus post-initiation in later development. Furthermore, 2,554 genes showed a significant differential gene expression in curly hair in comparison to straight hair. Neither TRPM2 nor CYP4F3 were identified as differentially expressed. Incidence of the genes in weighted co-expression networks associated with TRPM2 and CYP4F3, and prominent interactions of subsequent proteins with lipids and calcium-related pathways suggested calcium signaling and/or lipid metabolism as essential players in the induction of the curly hair as well as an ionic calcium-dependency to be a prominent factor for the maintenance of this phenotype. Subsequently, our study highlights the complex interrelations and dependencies of mutant genes TRPM2 and CYP4F3 and associated gene expression patterns, allowing the initiation of curly hair type during the development of a piglet as well as the maintenance in adult individuals.

Project description:BackgroundPathogenic variants in DSP associate with cardiac and cutaneous manifestations including arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy, curly or wavy hair, and palmoplantar keratoderma (PPK). Episodes of myocardial inflammation associated with DSP cardiomyopathy might be confused in clinical work with myocarditis of other etiologies such as viral. Cardiac magnetic resonance imaging (CMR) may help in differential diagnosis.Methods and resultsThis study comprised 49 Finnish patients: 34 participants from families with suspected DSP cardiomyopathy (9 index patients and 25 family members) and 15 patients with myocarditis. All 34 participants underwent genetic testing and cardiac evaluation, and 29 of them also underwent CMR. Participants with the DSP variant, numbering 22, were dermatologically examined. The 15 patients with myocarditis underwent CMR and were evaluated during their hospitalization.A heterozygous truncating DSP c.6310delA p.(Thr2104Glnfs*12) variant was confirmed in 29 participants. Only participants with the DSP variant had pacemakers and life-threatening ventricular arrhythmias. Of the participants with the DSP variant, 24% fulfilled cardiomyopathy criteria, and the median age at diagnosis was 53. Upon CMR, myocardial edema was found to be more common in patients with myocarditis. Both groups had a substantial percentage of late gadolinium enhancement (LGE). A ring-like LGE and increased trabeculation were observed only in participants with the DSP variant. All the studied participants with the DSP variant had PPK and curly or wavy hair. Hyperkeratosis developed before the age of 20 in most patients.ConclusionsThe DSP c.6310delA p.(Thr2104Glnfs*12) variant associates with curly hair, PPK, and arrhythmogenic cardiomyopathy with increased trabeculation. Cutaneous symptoms developing in childhood and adolescence might help recognize these patients at an earlier stage. CMR, together with dermatologic characteristics, may help in diagnosis.

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Dataset Information

The what, why and how of curly hair: a review.

Publications

The what, why and how of curly hair: a review.

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