[Oculocutaneous and ocular albinism]

Human Hair Graying Revisited: Principles, Misconceptions, and Key Research Frontiers

Hair graying holds psychosocial importance and serves as an excellent model for studying human pigmentation and aging in an accessible miniorgan. Current evidence suggests that graying results from an interindividually varying mixture of cumulative oxidative and DNA damage, excessive mTORC1 activity, melanocyte senescence, and inadequate production of pigmentation-promoting factors in the hair matrix. Various regulators modulate this process, including genetic factors (DNA repair defects and IRF4 sequence variation, peripheral clock genes, P-cadherin signaling, neuromediators, HGF, KIT ligand secretion, and autophagic flux. This leads to reduced MITF- and tyrosinase-controlled melanogenesis, defective melanosome transfer to precortical matrix keratinocytes, and eventual depletion of hair follicle (HF) pigmentary unit (HFPU) melanocytes and their local progenitors. Graying becomes irreversible only when bulge melanocyte stem cells are also depleted, occurring later in this process. Distinct pigmentary microenvironments are created as the HF cycles: early anagen is the most conducive phase for melanocytic reintegration and activation, and only during anagen can the phenotype of hair graying and repigmentation manifest, whereas the HFPU disassembles during catagen. The temporary reversibility of graying is highlighted by several drugs and hormones that induce repigmentation, indicating potential target pathways. We advise caution in directly applying mouse model concepts, define major open questions, and discuss future human antigraying strategies.

Issues in the surgical management of skin squamous cell cancers in albinos-experience of two surgical oncology units in Burkina Faso

BACKGROUND AND OBJECTIVES

Skin cancers in albinos are frequent in sunny countries. The surgeon plays a crucial role in their treatment. The objective was to describe the challenges of surgical management of skin cancer in albinos.

METHODS

Retrospective, descriptive, and multicenter study on skin cancer surgery in albinos performed over the past 14 years in Ouagadougou. We were interested in surgery indications, techniques, and results. Survival was assessed using the Kaplan-Meier method. Comparisons of proportions were made by Student's t-test.

RESULTS

The cancers were multiple synchronous in 41.3%. We identified 46 albinos with 71 skin cancers. Surgery was performed in 93%. Lesions were located on the back, upper limbs, and head and face in 40.9%, 30.3%, and 16.7%, respectively. Precancerous lesions were treated concomitantly in 23.6%. The surgery consisted of a lumpectomy. Direct suturing and mobilization of flaps allowed skin coverage in 17.9% and 34.3%, respectively. Lymph node dissection was associated with the limbs in 73.1% of localizations. The average number of lymph nodes removed was 11, with extremes of 7 and 14. Node invasion was noted in 16 out of 19 cases. The resection margins were invaded in 7.5% and required surgical revision. Recurrences were noted in 8.9% of cases. Overall 2-year survival rate was 55.8%.

CONCLUSIONS

Surgery must meet the triple challenge of treating single or multiple synchronous cancers, precancerous lesions, and allowing good healing. Early diagnosis would reduce the rate of secondary healing and improve survival. The absence of extemporaneous histology and the large size of the tumors associated with the delay in diagnosis meant that surgery, whenever possible, was limited to wide and deep resection, to ensure healthy margins.

Human equivalent doses of L-DOPA rescues retinal morphology and visual function in a murine model of albinism

L-DOPA is deficient in the developing albino eye, resulting in abnormalities of retinal development and visual impairment. Ongoing retinal development after birth has also been demonstrated in the developing albino eye offering a potential therapeutic window in humans. To study whether human equivalent doses of L-DOPA/Carbidopa administered during the crucial postnatal period of neuroplasticity can rescue visual function, OCA C57BL/6 J-c2J OCA1 mice were treated with a 28-day course of oral L-DOPA/Carbidopa at 3 different doses from 15 to 43 days postnatal age (PNA) and for 3 different lengths of treatment, to identify optimum dosage and treatment length. Visual electrophysiology, acuity, and retinal morphology were measured at 4, 5, 6, 12 and 16 weeks PNA and compared to untreated C57BL/6 J (WT) and OCA1 mice. Quantification of PEDF, βIII-tubulin and syntaxin-3 expression was also performed. Our data showed impaired retinal morphology, decreased retinal function and lower visual acuity in untreated OCA1 mice compared to WT mice. These changes were diminished or eliminated when treated with higher doses of L-DOPA/Carbidopa. Our results demonstrate that oral L-DOPA/Carbidopa supplementation at human equivalent doses during the postnatal critical period of retinal neuroplasticity can rescue visual retinal morphology and retinal function, via PEDF upregulation and modulation of retinal synaptogenesis, providing a further step towards developing an effective treatment for albinism patients.

Development and usability evaluation of a mHealth application for albinism self-management

BACKGROUND

Reduced or absence of melanin poses physical, social, and psychological challenges to individuals with albinism. Mobile health (mHealth) applications have the potential to improve the accessibility of information and services while reducing time and costs. This study aimed to develop and evaluate a mHealth application for self-management of albinism.

METHODS

This applied study was conducted in two stages (development and evaluation) in 2022. Initially, the functional requirements were determined, and the conceptual model of the application was then developed using Microsoft Visio 2021. In the second phase, the application was evaluated using the Mobile Application Usability Questionnaire (MAUQ) involving patients with albinism to reflect their views on the usability of the application.

RESULTS

The key capabilities of the application included: reminders, alerts, educational content, useful links, storage and exchange of images of skin lesions, specialist finder, and notifications for albinism-relevant events. Twenty-one users with albinism participated in the usability testing of the application. The users were predominantly satisfied with the application (5.53 ± 1.10; Max: 7.00).

CONCLUSIONS

The findings of this study suggest that the developed mobile application could assist individuals with albinism to effectively manage their condition by considering the users' requirements and services that the application should deliver.

The genetic basis and potential molecular mechanism of yellow-albino northern snakehead (Channa argus)

Body colour is an important economic trait for commercial fishes. Recently, a new colour morph displaying market-favoured yellow skin (termed as yellow-mutant, YM) of northern snakehead (Channa argus) was discovered in China. We confirmed that YM snakehead is an albino with complete loss of melanin in the skin and eyes by histological and ultrastructural observations, and inherited as a recessive Mendelian trait. By applying genomic analysis approaches, in combination with gene knockdown and rescue experiments, we suggested a non-sense mutation in slc45a2 (c.383G > A) is the causation for the YM snakehead. Notably, significantly higher levels of key melanogenesis genes (tyr, tyrp1, dct and pmel) and phospho-MITF protein were detected in YM snakehead than those in wild-type individuals, and the underlying mechanism was further investigated by comparative transcriptomic analysis. Results revealed that differential expressed genes involved in pathways like MAPK, WNT and calcium signalling were significantly induced in YM snakehead, which might account for the increased amount of melanogenesis elements, and presumably be stimulated by fibroblast-derived melanogenic factors in a paracrine manner. Our study clarified the genetic basis of colour variation in C. argus and provided the preliminary clue indicating the potential involvement of fibroblasts in pigmentation in fish.

[The history of skin color is the history of mankind!]

In the early days of mankind, at a time when various other human species populated the earth coexisting with Homo sapiens, the genetic mixing of mankind had already begun. Today, paleogenetics-as a branch of human genetic research-can prove that individuals from the most diverse human species already produced offspring together long before our era. This intermixing was supported from the beginning by massive migratory movements that started in East Africa and led first Homo neanderthalensis and much later also Homo sapiens to as far as Europe-two human species of which we know today that they were lighter-skinned than their ancestors. The adaptation to life in different climatic zones led to development of specific characteristics, which, in addition to physique and physiognomy, also affect specific features of the skin and the integumentary system. The most striking feature among these is the skin color and all associated skin-specific characteristics. These characteristics ensure special protection, but can also be the origin for specific diseases. Any division of Homo sapiens into races has been scientifically refuted. Due to ongoing genetic mixing of mankind, skin color, hair color and all associated characteristics should always be considered individually.

Clinical and Mutation Spectrum of Autosomal Recessive Non-Syndromic Oculocutaneous Albinism (nsOCA) in Pakistan: A Review

Oculocutaneous albinism (OCA) is an autosomal recessive syndromic and non-syndromic defect with deficient or a complete lack of the melanin pigment. The characteristics of OCA appears in skin, hair, and eyes with variable degree of pigmentation. Clinical manifestations of OCA include nystagmus, photophobia, reduced visual acuity, hypo-plastic macula, and iris trans-illumination. There are eight OCA types (OCA1–8) documented with non-syndromic characteristics. Molecular studies identified seven genes linked to the OCA phenotype (TYR, OCA2, TYRP1, SLC45A2, SLC24A5, C10orf11, and DCT) and one locus (OCA5) in consanguineous and sporadic albinism. The complications of OCA result in skin cancer and variable syndromes such as Hermansky–Pudlak syndrome (HPS) Chediak–Higashi syndrome (CHS). In the Pakistani population, autosomal recessive non-syndromic OCA is common and is associated with a large number of consanguineous families, and mutations in genes of non-syndromic types are reported. This review highlights the updates on the genetic mutation of OCA genes reported from Pakistani families. Several studies reported the genetic mutations in OCA1, OCA2, OCA3, OCA4, and OCA6 albinism in Pakistani families. A locus, OCA5, was also reported from the Pakistani population, but the gene has not been identified. A new type of OCA8 was identified due to the DCT gene mutation, and it is also reviewed here.

[Method of surgical treatment of patients with oculocutaneous albinism using artificial iris]

Oculocutaneous albinism is a group of autosomal recessive disorders that directly affect the hypopigmentation of the skin, hair, and eyes. According to the World Health Organization, albinism occurs in 1 out of 20 000 people in Europe and North America. Congenital changes in the organ of vision in albinism lead to a significant decrease in the visual functions of patients, worsening their quality of life.

PURPOSE

To study the results of surgical treatment with implantation of an artificial iris as a diaphragm element in patients with albinism.

MATERIAL AND METHODS

This article was based on the examination and treatment of 2 patients suffering from oculocutaneous albinism, which is characterized by hypopigmentation of the iris and retinal pigment epithelium of the retina, foveolar hypoplasia, low visual acuity, nystagmus, strabismus and excruciating photophobia. The patients were implanted an artificial iris in both eyes with fixation in the capsular bag in the first patient, and in the ciliary sulcus in the second.

RESULTS

In both patients, complaints of photophobia and optical phenomena have ceased. Visual acuity increased to 0.2 and remained without regression throughout the entire period of observation. Intraocular pressure and hydrodynamic parameters also remained stable throughout the observation period. The artificial irises were observed by ultrabiomicroscopy to remain in a stable position both when it was implanted in the capsule bag, and when it was seamlessly fixed in the ciliary sulcus.

CONCLUSION

The surgical interventions relieved patients from glare, at the same time improving visual acuity without correction, as well as achieving a pronounced cosmetic effect and visual rehabilitation. Artificial irises have proven to be a safe and effective way to treat patients with oculocutaneous albinism.

Genetic Causes of Oculocutaneous Albinism in Pakistani Population

Melanin pigment helps protect our body from broad wavelength solar radiation and skin cancer. Among other pigmentation disorders in humans, albinism is reported to manifest in both syndromic and nonsyndromic forms as well as with varying inheritance patterns. Oculocutaneous albinism (OCA), an autosomal recessive nonsyndromic form of albinism, presents as partial to complete loss of melanin in the skin, hair, and iris. OCA has been known to be caused by pathogenic variants in seven different genes, so far, according to all the currently published population studies. However, the detection rate of alleles causing OCA varies from 50% to 90%. One of the significant challenges of uncovering the pathological variant underlying disease etiology is inter- and intra-familial locus heterogeneity. This problem is especially pertinent in highly inbred populations. As examples of such familial locus heterogeneity, we present nine consanguineous Pakistani families with segregating OCA due to variants in one or two different known albinism-associated genes. All of the identified variants are predicted to be pathogenic, which was corroborated by several in silico algorithms and association with diverse clinical phenotypes. We report an individual affected with OCA carries heterozygous, likely pathogenic variants in TYR and OCA2, raising the question of a possible digenic inheritance. Altogether, our study highlights the significance of exome sequencing for the complete genetic diagnosis of inbred families and provides the ramifications of potential genetic interaction and digenic inheritance of variants in the TYR and OCA2 genes.

Melanosome transport and regulation in development and disease

Melanosomes are specialized membrane-bound organelles that synthesize and organize melanin, ultimately providing color to the skin, hair, and eyes. Disorders in melanogenesis and melanosome transport are linked to pigmentary diseases, such as Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, and Griscelli syndrome. Clinical cases of these pigmentary diseases shed light on the molecular mechanisms that control melanosome-related pathways. However, only an improved understanding of melanogenesis and melanosome transport will further the development of diagnostic and therapeutic approaches. Herein, we review the current literature surrounding melanosomes with particular emphasis on melanosome membrane transport and cytoskeleton-mediated melanosome transport. We also provide perspectives on melanosome regulatory mechanisms which include hormonal action, inflammation, autophagy, and organelle interactions.

The biology of human hair greying

Hair greying (canities) is one of the earliest, most visible ageing-associated phenomena, whose modulation by genetic, psychoemotional, oxidative, senescence-associated, metabolic and nutritional factors has long attracted skin biologists, dermatologists, and industry. Greying is of profound psychological and commercial relevance in increasingly ageing populations. In addition, the onset and perpetuation of defective melanin production in the human anagen hair follicle pigmentary unit (HFPU) provides a superb model for interrogating the molecular mechanisms of ageing in a complex human mini-organ, and greying-associated defects in bulge melanocyte stem cells (MSCs) represent an intriguing system of neural crest-derived stem cell senescence. Here, we emphasize that human greying invariably begins with the gradual decline in melanogenesis, including reduced tyrosinase activity, defective melanosome transfer and apoptosis of HFPU melanocytes, and is thus a primary event of the anagen hair bulb, not the bulge. Eventually, the bulge MSC pool becomes depleted as well, at which stage greying becomes largely irreversible. There is still no universally accepted model of human hair greying, and the extent of genetic contributions to greying remains unclear. However, oxidative damage likely is a crucial driver of greying via its disruption of HFPU melanocyte survival, MSC maintenance, and of the enzymatic apparatus of melanogenesis itself. While neuroendocrine factors [e.g. alpha melanocyte-stimulating hormone (α-MSH), adrenocorticotropic hormone (ACTH), ß-endorphin, corticotropin-releasing hormone (CRH), thyrotropin-releasing hormone (TRH)], and micropthalmia-associated transcription factor (MITF) are well-known regulators of human hair follicle melanocytes and melanogenesis, how exactly these and other factors [e.g. thyroid hormones, hepatocyte growth factor (HGF), P-cadherin, peripheral clock activity] modulate greying requires more detailed study. Other important open questions include how HFPU melanocytes age intrinsically, how psychoemotional stress impacts this process, and how current insights into the gerontobiology of the human HFPU can best be translated into retardation or reversal of greying.

Determining the Topic Evolution and Sentiment Polarity for Albinism in a Chinese Online Health Community: Machine Learning and Social Network Analysis

BACKGROUND

There are more than 6000 rare diseases in existence today, with the number of patients with these conditions rapidly increasing. Most research to date has focused on the diagnosis, treatment, and development of orphan drugs, while few studies have examined the topics and emotions expressed by patients living with rare diseases on social media platforms, especially in online health communities (OHCs).

OBJECTIVE

This study aimed to determine the topic categorizations and sentiment polarity for albinism in a Chinese OHC, Baidu Tieba, using multiple methods. The OHC was deeply mined using topic mining, social network analysis, and sentiment polarity analysis. Through these methods, we determined the current situation of community construction, identifying the ongoing needs and problems experienced by people with albinism in their daily lives.

METHODS

We used the albinism community on the Baidu Tieba platform as the data source in this study. Term frequency-inverse document frequency, latent dirichlet allocation models, and naive Bayes were employed to mine the various topic categories. Social network analysis, which was completed using the Gephi tool, was employed to analyze the evolution of the albinism community. Sentiment polarity analysis was performed using a long short-term memory algorithm.

RESULTS

We identified 8 main topics discussed in the community: daily sharing, family, interpersonal communication, social life and security, medical care, occupation and education, beauty, and self-care. Among these topics, daily sharing represented the largest proportion of the discussions. From 2012 to 2019, the average degree and clustering coefficient of the albinism community continued to decline, while the network center transferred from core communities to core users. A total of 68.43% of the corpus was emotional, with 35.88% being positive and 32.55% negative. There were statistically significant differences in the distribution of sentiment polarity between topics (P<.001). Negative emotions were twice as high as positive emotions in the social life and security topic.

CONCLUSIONS

The study reveals insights into the emotions expressed by people with albinism in the Chinese OHC, Baidu Tieba, providing health care practitioners with greater appreciation of the current emotional support needed by patients and the patient experience. Current OHCs do not exert enough influence due to limited effective organization and development. Health care sectors should take greater advantage of OHCs to support vulnerable patients with rare diseases to meet their evidence-based needs.

Comorbidity of sickle cell trait and albinism: a cross-sectional survey in the Democratic Republic of the Congo

INTRODUCTION

Sickle Cell Disease (SCD) and albinism are both recessive hereditary diseases in human kind with a high prevalence in sub-Saharan Africa. This study aimed to determinate the prevalence of sickle cell trait in people living with albinism (PLA).

METHODS

a cross-sectional descriptive survey was conducted in PLA attending the "Hôpital du Cinquantenaire de Kisangani". In total, by non-probabilistic convenience sampling, 82 albinos and 139 non-albinos and without any antecedents of albinism in their family were included, selected from students in the Faculty of Medicine and Pharmacy at the University of Kisangani. Blood samples were collected on "dried blood spot" and analyzed by mass spectrometry at CHU of Liège. Data were entered into an Excel file and analysed on SPSS 20.0 (Chicago, IL).

RESULTS

forty-six of the 82 albinos (56.1%) were female and 43.9% male with a sex ratio of 1.28. Among albinos, 18.3% had hemoglobin AS (HbAS) and 81.7% hemoglobin AA (HbAA) compared to 18% of subjects with hemoglobin AS and 82% hemoglobin AA in the control group. The difference was not statistically significant (Chi-square=0.003, ddl=1, p=0.9544).

CONCLUSION

this study highlighted that the prevalence of the sickle cell trait is high among people living with albinism, but does not differ from that observed in non-albinos in the Democratic Republic of the Congo. It is therefore important to raise awareness among this category of people about sickle cell disease and the importance of its premarital screening.