Acquired cutis laxa: a clinical review

Acquired cutis laxa (ACL) is a rare, nonhereditary cutaneous disorder characterized by saggy inelastic skin. It has been associated with various inflammatory, autoimmune, and neoplastic diseases, in addition to certain infections and medication. This article reviews ACL the demographical, clinical, and histological features of ACL, focusing on all associated disorders. Additionally, this review article provides an in-depth discussion of all the mechanisms implicated in the pathogenesis of ACL and all therapeutic options available; we also present an algorithm for the workup of patients with ACL. A systematic literature review was performed on PubMed/Medline and EMBASE databases, searching for all available articles on ACL with no limits on participant age, race, sex, nationality, or publication date. Ninety-eight articles were included. The total number of included patients was 110, with a mean age of 36.4 years at presentation (range 0.25-78) and a M:F sex ratio of 1.24. ACL was most commonly associated with inflammatory disorders (43%) followed by neoplastic disorders (27%). In 73% of the neoplastic-associated cases, ACL occurred on average 2.4 years before malignancy onset. ACL occurs months to years after an underlying inflammatory disorder. In 10% of the cases, ACL was associated with a particular drug, and in 2%, it was associated with specific infections. Data were derived from case reports, case series, letters to editors, observational studies, and abstracts. Limitations include the accuracy of published data, potential patient selection, and reporting bias. Dermatologists should be alert to these associations to provide adequate screening and management of patients with ACL.

Acquired cutis laxa secondary to acute generalized exanthematous pustulosis: A case report and mini-review of literature

Cutis laxa presents as loose redundant skin folds and loss of dermal elastic tissue. Acquired cutis laxa (ACL) is characterized by later onset. It has been reported in association with various kinds of neutrophilic dermatoses, drugs, metabolic disorders, and autoimmune disorders. Acute generalized exanthematous pustulosis (AGEP) is usually classified as a severe cutaneous adverse reaction characterized by T cell-mediated neutrophilic inflammation. We previously reported a mild case of AGEP caused by gemcitabine in a 76-year-old man. Here, we report a case of ACL secondary to AGEP in this patient. He developed AGEP 8 days after gemcitabine administration. Four weeks after beginning chemotherapy, his skin had become atrophic, loose, and darkly pigmented in areas previously affected by AGEP. Histopathological examination revealed edema and perivascular lymphocytic infiltration but no neutrophilic infiltration in the upper dermis. Elastica van Gieson staining showed that the elastic fibers in all layers of the dermis were sparse and shortened. Electron microscopy showed elevated numbers of fibroblasts and altered elastic fibers with irregular surfaces. Finally, he was diagnosed with ACL secondary to AGEP. He was treated with topical corticosteroids and oral antihistamines. Skin atrophy decreased over 3 months. We summarize 36 cases (including our case) with ACL secondary to neutrophilic dermatosis. We discuss these clinical manifestations, causative neutrophilic disorders, treatments, and outcomes. The mean age of patients was 3.5 years. Five patients had an aortic lesion as systemic involvement. The most common causative neutrophilic disorders were Sweet syndrome (24 cases), followed by urticaria-like neutrophilic dermatosis (11 cases). There were no cases of AGEP except for our case. Although treatment for ACL secondary to neutrophilic dermatosis, such as dapsone, oral prednisolone, adalimumab, and plastic surgery were reported, ACL is generally refractory and irreversible. Our patient was considered reversibly cured due to the absence of continuous neutrophil-mediated elastolysis.

WDR72 Mutations Associated with Amelogenesis Imperfecta and Acidosis

Dental enamel malformations, or amelogenesis imperfecta (AI), can be isolated or syndromic. To improve the prospects of making a successful diagnosis by genetic testing, it is important that the full range of genes and mutations that cause AI be determined. Defects in WDR72 (WD repeat-containing protein 72; OMIM *613214) cause AI, type IIA3 (OMIM #613211), which follows an autosomal recessive pattern of inheritance. The defective enamel is normal in thickness, severely hypomineralized, orange-brown stained, and susceptible to attrition. We identified 6 families with biallelic WDR72 mutations by whole exome sequence analyses that perfectly segregated with the enamel phenotype. The novel mutations included 3 stop-gains [NM_182758.2: c.377G>A/p.(Trp126*), c.1801C>T/p.(Arg601*), c.2350A>T/p.(Arg784*)], a missense mutation [c.1265G>T/p.(Gly422Val)], and a 62,138-base pair deletion (NG_017034.2: g.35441_97578del62138) that removed WDR72 coding exons 3 through 13. A previously reported WDR72 frameshift was also observed [c.1467_1468delAT/p.(Val491Aspfs*8)]. Three of the affected patients showed decreased serum pH, consistent with a diagnosis of renal tubular acidosis. Percentiles of stature and body weight varied among 8 affected individuals but did not show a consistent trend. These studies support that WDR72 mutations cause a syndromic form of AI and improve our ability to diagnose AI caused by WDR72 defects.

From Structure to Phenotype: Impact of Collagen Alterations on Human Health

The extracellular matrix (ECM) is a highly dynamic and heterogeneous structure that plays multiple roles in living organisms. Its integrity and homeostasis are crucial for normal tissue development and organ physiology. Loss or alteration of ECM components turns towards a disease outcome. In this review, we provide a general overview of ECM components with a special focus on collagens, the most abundant and diverse ECM molecules. We discuss the different functions of the ECM including its impact on cell proliferation, migration and differentiation by highlighting the relevance of the bidirectional cross-talk between the matrix and surrounding cells. By systematically reviewing all the hereditary disorders associated to altered collagen structure or resulting in excessive collagen degradation, we point to the functional relevance of the collagen and therefore of the ECM elements for human health. Moreover, the large overlapping spectrum of clinical features of the collagen-related disorders makes in some cases the patient clinical diagnosis very difficult. A better understanding of ECM complexity and molecular mechanisms regulating the expression and functions of the various ECM elements will be fundamental to fully recognize the different clinical entities.