The morbid cutaneous anatomy of the human genome revealed by a bioinformatic approach.

Computational approaches have been developed to prioritize candidate genes in disease gene identification. They are based on different pieces of evidences associating each gene with the given disease. In this study, 648 genes underlying genodermatoses have been compared to 1808 genes involved in other genetic diseases using a bioinformatic approach. These genes were studied at the structural, evolutionary and functional levels. Results show that genes underlying genodermatoses present longer CDS and have more exons. Significant differences were observed in nucleotide motif and amino-acid compositions. Evolutionary conservation analysis revealed that genodermatoses genes have less paralogs, more orthologs in Mouse and Dog and are less conserved. Functional analysis revealed that genodermatosis genes seem to be involved in immune system and skin layers. The Bayesian network model returned a rate of good classification of around 80%. This computational approach could help investigators working in the field of dermatology by prioritizing positional candidate genes for mutation screening.

Identification of a CDH12 potential candidate genetic variant for an autosomal dominant form of transgrediens and progrediens palmoplantar keratoderma in a Tunisian family.

Molecular diagnosis of rare inherited palmoplantar keratoderma (PPK) is still challenging. We investigated at the clinical and genetic level a consanguineous Tunisian family presenting an autosomal dominant atypical form of transgrediens and progrediens PPK to better characterize this ultrarare disease and to identify its molecular etiology. Whole-exome sequencing (WES), filtering strategies, and bioinformatics analysis have been achieved. Clinical investigation and follow up over 13 years of this Tunisian family with three siblings formerly diagnosed as an autosomal recessive form of Mal de Melela-like conducted us to reconsider its initial phenotype. Indeed, the three patients presented clinical features that overlap both Mal de Meleda and progressive symmetric erythrokeratoderma (PSEK). The mode of inheritance was also reconsidered, since the mother, initially classified as unaffected, exhibited a similar expression of the disease. WES analysis showed the absence of potentially functional rare variants in known PPKs or PSEK-related genes. Results revealed a novel heterozygous nonsynonymous variant in cadherin-12 gene (CDH12, NM_004061, c.1655C > A, p.Thr552Asn) in all affected family members. This variant is absent in dbSNP and in 50 in-house control exomes. In addition, in silico analysis of the mutated 3D domain structure predicted that this variant would result in cadherin-12 protein destabilization and thermal instability. Functional annotation and biological network construction data provide further supporting evidence for the potential role of CDH12 in the maintenance of skin integrity. Taken together, these results suggest that CDH12 gene is a potential candidate gene for an atypical presentation of an autosomal dominant form of transgrediens and progrediens PPK.

Matrix metalloproteinase-7 could be a predictor for acute inflammation in psoriatic patients.

PURPOSE: The pathogenesis of psoriasis is characterized by a disruption of extracellular matrix (ECM) in which matrix metalloproteinases (MMPs) participate actively. We aimed to determine MMP-7 level and its association with the inflammatory response in order to determine its usefulness as a biomarker for psoriasis prediction. We also aimed to determine its distribution in uninvolved and involved psoriatic skin to evaluate the probable role of MMP-7 in psoriasis pathogenesis. MATERIALS AND METHODS: We recruited 108 psoriatic patients and 133 healthy controls. MMP-7, tissue inhibitors of metalloproteinases (TIMPs) and interleukin-6 (IL-6) levels were measured by Enzyme-Linked Immunosorbent Assay (ELISA) assay. MMP-7 expression was detected by Immunohistochemistry (IHC) study. RESULTS: ECM turnover and inflammatory biomarker levels were significantly higher in psoriatic patients. MMP-7 revealed to be independently associated to psoriasis even after adjustment for different models. The area under the curve (AUC) of MMP-7 and inflammation Z-score were similar. MMP-7 was positively correlated with IL-6 and inflammation Z-score. Psoriasis severity (PASI) was correlated significantly with IL-6 (p = 0.007). The MMP-7 expression was detected in the epidermis of involved and uninvolved psoriatic skin. In involved skin, MMP-7 was expressed by basal and mostly suprabasal keratinocytes. In uninvolved skin, expression of MMP-7 was restricted to basal keratinocytes. CONCLUSION: MMP-7 is independently associated to psoriasis disease and to inflammatory response which make it a potential biomarker for this dermatosis.

Keratoacanthoma Centrifugum Marginatum: Response to Acitretin.

A previously healthy 70-year-old woman presented with a 5-month history of an asymptomatic keratotic, papulonodular plaque on her right forearm. The lesion started as a follicular papule followed by progressive peripheral proliferation. No record of trauma, contact with any chemicals, use of immunosuppressive drugs, or history of neoplasm was noted. Clinical examination showed an arciform plaque of 10×5 cm, with infiltrated raised borders and central atrophy (Figure 1). Drops of yellowish material exuded from the coalescent nodules constituting an elevated and indurate border. Results from physical and laboratory examinations revealed no internal organ malignancy. The remainder of the physical examination (x-ray of the forearm and serologies for HIV, hepatitis, and syphilis) was normal.

Prevalence, Etiology, and Risk Factors of Tinea Pedis and Tinea Unguium in Tunisia.

BACKGROUND: Foot mycoses are a frequent disease that represents a public health problem worldwide. OBJECTIVES: This study aims to evaluate the epidemiology of foot mycoses among Tunisian patients, in order to determine the fungal etiological agents and to identify possible risk factors. PATIENTS AND METHODS: A prospective study of three hundred and ninety-two patients was undertaken during one year (2013-2014). All subjects were asked to collect demographic data related to the risk factors of foot mycoses. A complete mycological diagnosis was carried out on all patients. RESULTS: A total of 485 samples were collected; tinea pedis and tinea unguium were confirmed in 88.2% of cases. Dermatophytes were isolated in 70.5% and the most frequent pathogen was Trichophyton rubrum (98.1%), followed by yeasts (17.7%) commonly Candida parapsilosis. Non-dermatophyte molds (NDMs) were observed in 8.02% cases and Fusarium sp. was the frequent genus (29.1%). The main predisposing factors of fungal foot infections were practicing ritual washing (56.6%) and frequentation of communal showers (50.5%). CONCLUSION: This is a recent survey of foot mycoses in Tunisia. Epidemiological studies can be useful to eradicate these infections and to provide further measures of hygiene and education.

Topical paromomycin with or without gentamicin for cutaneous leishmaniasis.

BACKGROUND: There is a need for a simple and efficacious treatment for cutaneous leishmaniasis with an acceptable side-effect profile. METHODS: We conducted a randomized, vehicle-controlled phase 3 trial of topical treatments containing 15% paromomycin, with and without 0.5% gentamicin, for cutaneous leishmaniasis caused by Leishmania major in Tunisia. We randomly assigned 375 patients with one to five ulcerative lesions from cutaneous leishmaniasis to receive a cream containing 15% paromomycin-0.5% gentamicin (called WR 279,396), 15% paromomycin alone, or vehicle control (with the same base as the other two creams but containing neither paromomycin nor gentamicin). Each lesion was treated once daily for 20 days. The primary end point was the cure of the index lesion. Cure was defined as at least 50% reduction in the size of the index lesion by 42 days, complete reepithelialization by 98 days, and absence of relapse by the end of the trial (168 days). Any withdrawal from the trial was considered a treatment failure. RESULTS: The rate of cure of the index lesion was 81% (95% confidence interval [CI], 73 to 87) for paromomycin-gentamicin, 82% (95% CI, 74 to 87) for paromomycin alone, and 58% (95% CI, 50 to 67) for vehicle control (P<0.001 for each treatment group vs. the vehicle-control group). Cure of the index lesion was accompanied by cure of all other lesions except in five patients, one in each of the paromomycin groups and three in the vehicle-control group. Mild-to-moderate application-site reactions were more frequent in the paromomycin groups than in the vehicle-control group. CONCLUSIONS: This trial provides evidence of the efficacy of paromomycin-gentamicin and paromomycin alone for ulcerative L. major disease. (Funded by the Department of the Army; ClinicalTrials.gov number, NCT00606580.).

Differential impact of consanguineous marriages on autosomal recessive diseases in Tunisia.

OBJECTIVES: Consanguinity is common in Tunisia. However, little information exists on its impact on recessive disorders. In this study, we evaluate the impact of consanguineous marriages on the occurrence of some specific autosomal recessive disorders and consider how other factors, such as population substructure and mutation frequency, may be of equal importance in disease prevalence. METHODS: Consanguinity profiles were retrospectively studied among 425 Tunisian patients suffering from autosomal recessive xeroderma pigmentosum, dystrophic epidermolysis bullosa, nonsyndromic retinitis pigmentosa, Gaucher disease, Fanconi anemia, glycogenosis type I, and ichthyosis, and compared to those of a healthy control sample. RESULTS: Consanguinity was observed in 341 cases (64.94%). Consanguinity rates per disease were 75.63, 63.64, 60.64, 61.29, 57.89, 73.33, and 51.28%, respectively. First-cousin marriages were the most common form of consanguinity (48.94%) with the percentages of 55.46, 45.46, 47.87, 48.39, 45.61, 56.66, and 35.90%, respectively. A very high level of geographic endogamy was also observed (93.92%), with the values by disease ranging between 75.86 and 96.64%. We observed an overall excess risk associated to consanguinity of nearly sevenfold which was proportional to the number of affected siblings and the frequency of disease allele in the family. Consanguinity was significantly associated with the first five cited diseases (odds ratio = 24.41, 15.17, 7.5, 5.53, and 5.07, respectively). However, no meaningful effects were reported among the remaining diseases. CONCLUSIONS: This study reveals a variation in the excess risk linked to consanguinity according to the type of disorder, suggesting the potential of cryptic population substructure to contribute to disease incidence in populations with complex social structure like Tunisia. It also emphasizes the role of other health and demographic aspects such as mutation frequency and reproductive replacement in diseases etiology.

Immunohistological study of tight junction protein expression in mal de Meleda.

Mal de Meleda (MdM, MIM: 248300) is a rare autosomal recessive skin disorder characterized by diffuse palmoplantar keratoderma and transgressive keratosis with onset in early infancy. The gene responsible for MdM, ARS, encodes for Secreted Lys6/Plaur domain-containing protein 1 which is essential for epidermal homeostasis. Tight junctions have been proposed to have two mutually exclusive functions: a fence function which prevents the mixing of membrane proteins between the apical and basolateral membranes; and a gate function which controls the paracellular passage of ions and solutes between cells. In this study we report immunohistochemical investigations of tight junction proteins claudin-1 and occludin in MdM Tunisian families. Nine skin biopsies from patients with MdM were analyzed. The control group was formed by skin biopsies belonging to healthy individuals. Immunohistochemical study was performed on fixed sections from biopsies of four microns with the following polyclonal antibodies: anti-claudin-1 and anti-occludin. In control skin, claudin-1 exhibited membrane expression throughout the epidermis with increasing and upward intensity, whereas occludin was detected in the cell membrane of keratinocytes of the stratum granulosum. In MdM skin, claudin-1 was expressed throughout the thickness of the spinous layers with membrane staining, and occludin had cytoplasmic staining in the granular layer. The immunohistochemical expression of TJ proteins in MdM patients harbors premature expression of occludin and decreased expression of claudin-1, highlighting further evidence for disorders in epidermal homeostasis.

Lipomembranous Panniculitis Associated With Venous Insufficiency, Morphea, and Psoriasis.

A 45-year-old obese woman diagnosed with morphea on her leg, presented with a 7-year history of cutaneous depressions on her thigh, chest, and back. She recalled that the lesions followed a three-phase course: edema, hardening, and atrophy. Clinical examination revealed a cutaneous indurated depression localized to the thigh, chest, and the back (Figure 1).

Methotrexate-induced necrolysis in tumoral-stage mycosis fungoides: a challenging diagnosis.

Methotrexate-induced cutaneous ulceration is a rare but potentially serious drug adverse reaction. This adverse reaction of methotrexate therapy has been initially described in psoriasis patients and is unusual in patients with cutaneous T-cell lymphoma. In 1978, Mc Donald et al reported the first three cases of cutaneous ulcerations in patients treated for a mycosis fungoides with intravenous infusions of methotrexate. Since then, few cases of methotrexate-induced skin ulcers in patients with mycosis fungoides have been published. We report an additional patient with erythrodermic mycosis fungoides who developed cutaneous ulcerations as a sole manifestation of methotrexate toxicity.

Proliferative fasciitis in the abdominal region.

A 30-year old man with no trauma history presented to our department of dermatology with a 2-year history of abdominal painful masses. The spontaneous pain and tenderness in the abdominal region gradually worsened. Physical examination revealed 3 firm, irregular subcutaneous nodules measuring 1 x 0.5 cm, which were movable and unattached to the overlying skin. One of the nodules was ulcerated (Figure 1). Histopathologic examination showed spindle-shaped fibroblast cells intermingled with gangliocyte-like giant cells in the hypodermis with an infiltrate made of lymphocytes and histiocytes (Figure 2 and Figure 3). The immunohistochemical staining showed the negativity of the fusiform cells and the gangliocyte-like cells to anti-S100 protein and to anti-smooth muscle actin.

[Severe childhood atopic dermatitis]. / La dermatite atopique severe de I'enfant.

BACKGROUND: Atopic dermatitis (AD) is a chronic relapsing eczematous skin disease. It represents one of the symptoms of atopic diathesis. DA affects usually infants and children. aim : The aim of our study is to draw up the epidemiological, clinical features, treatment and outcome of severe childhood AD through a hospital series. methods: A retrospective study of 24 cases of severe childhood AD hospitalized in the Dermatology Department of La Rabta hospital of Tunis was conducted during a 28 year-period (1981 - 2009). results: The hospital incidence of severe childhood AD was 0,085‰. Patient's mean age at the beginning was 14 months. The sex ratio H/F was 1.66. Cutaneous manifestations occurred preferentially in face (75%). Generalized eczema was observed in 37.5% of cases. Pruritus and xerosis were constant. The mean duration of hospitalization was 11 days. Topical corticosteroids was the most effective method of treating severe DA, associated with antiseptic solutions emollient and antihistaminic drugs. Infectious complications were noted in 50% of cases. Ocular complications were observed in 16.7% of cases. Recurrences were reported in 9 cases. Conclusion :AD is an inflammatory, chronically relapsing, and pruritic skin disorder developing in a xerotic skin. Severe AD in childhood is rare in Tunisia. It requires a good understanding of therapeutic modalities by the patient and his family. It is a cause of important morbidity and it may have a bad impact on quality of life.

Facial Hyperpigmentation: A Rare Side Effect of Adalimumab.

This report describes a case of facial hyperpigmentation in a patient with Crohn's disease receiving adalimumab, a tumor necrosis factor (TNF)-alpha inhibitor. The onset of hyperpigmentation coincided with adalimumab administration, and its discontinuation resulted in significant improvement. Histopathological findings suggest a postinflammatory process at the dermo-epidermal junction. However, the precise mechanism remains unclear.

Becker Nevus Syndrome: A Rare Entity but Important to Recognize.

Becker's nevus syndrome is defined by the association of a Becker nevus with homolateral breast hypoplasia or more rarely skeletal cutaneous or muscle deformities. Early diagnosis is important, especially in female patients to prevent and treat breast hypoplasia. We report two cases of Becker nevus syndrome with serious functional impairment and discuss possible treatment options.

Corrigendum: Current phenotypic and genetic spectrum of syndromic deafness in Tunisia: paving the way for precision auditory health.

[This corrects the article DOI: 10.3389/fgene.2024.1384094.].

Current phenotypic and genetic spectrum of syndromic deafness in Tunisia: paving the way for precision auditory health.

Hearing impairment (HI) is a prevalent neurosensory condition globally, impacting 5% of the population, with over 50% of congenital cases attributed to genetic etiologies. In Tunisia, HI underdiagnosis prevails, primarily due to limited access to comprehensive clinical tools, particularly for syndromic deafness (SD), characterized by clinical and genetic heterogeneity. This study aimed to uncover the SD spectrum through a 14-year investigation of a Tunisian cohort encompassing over 700 patients from four referral centers (2007-2021). Employing Sanger sequencing, Targeted Panel Gene Sequencing, and Whole Exome Sequencing, genetic analysis in 30 SD patients identified diagnoses such as Usher syndrome, Waardenburg syndrome, cranio-facial-hand-deafness syndrome, and H syndrome. This latter is a rare genodermatosis characterized by HI, hyperpigmentation, hypertrichosis, and systemic manifestations. A meta-analysis integrating our findings with existing data revealed that nearly 50% of Tunisian SD cases corresponded to rare inherited metabolic disorders. Distinguishing between non-syndromic and syndromic HI poses a challenge, where the age of onset and progression of features significantly impact accurate diagnoses. Despite advancements in local genetic characterization capabilities, certain ultra-rare forms of SD remain underdiagnosed. This research contributes critical insights to inform molecular diagnosis approaches for SD in Tunisia and the broader North-African region, thereby facilitating informed decision-making in clinical practice.