Germline intergenic duplications at Xq26.1 underlie Bazex-Dupré-Christol basal cell carcinoma susceptibility syndrome.

BACKGROUND: Bazex-Dupré-Christol syndrome (BDCS; MIM301845) is a rare X-linked dominant genodermatosis characterized by follicular atrophoderma, congenital hypotrichosis and multiple basal cell carcinomas (BCCs). Previous studies have linked BDCS to an 11·4-Mb interval on chromosome Xq25-q27.1. However, the genetic mechanism of BDCS remains an open question. OBJECTIVES: To investigate the genetic aetiology and molecular mechanisms underlying BDCS. METHODS: We ascertained multiple individuals from eight unrelated families affected with BDCS (F1-F8). Whole-exome (F1 and F2) and genome sequencing (F3) were performed to identify putative disease-causing variants within the linkage region. Array comparative genomic hybridization and quantitative polymerase chain reaction (PCR) were used to explore copy number variations, followed by long-range gap PCR and Sanger sequencing to amplify the duplication junctions and to define the head-tail junctions. Hi-C was performed on dermal fibroblasts from two affected individuals with BDCS and one control. Public datasets and tools were used to identify regulatory elements and transcription factor binding sites within the minimal duplicated region. Immunofluorescence was performed in hair follicles, BCCs and trichoepitheliomas from patients with BDCS and sporadic BCCs. The ACTRT1 variant c.547dup (p.Met183Asnfs*17), previously proposed to cause BDCS, was evaluated with t allele frequency calculator. RESULTS: In eight families with BDCS, we identified overlapping 18-135-kb duplications (six inherited and two de novo) at Xq26.1, flanked by ARHGAP36 and IGSF1. Hi-C showed that the duplications did not affect the topologically associated domain, but may alter the interactions between flanking genes and putative enhancers located in the minimal duplicated region. We detected ARHGAP36 expression near the control hair follicular stem cell compartment, and found increased ARHGAP36 levels in hair follicles in telogen, in BCCs and in trichoepitheliomas from patients with BDCS. ARHGAP36 was also detected in sporadic BCCs from individuals without BDCS. Our modelling showed the predicted maximum tolerated minor allele frequency of ACTRT1 variants in control populations to be orders of magnitude higher than expected for a high-penetrant ultra-rare disorder, suggesting loss of function of ACTRT1 variants to be an unlikely cause for BDCS. CONCLUSIONS: Noncoding Xq26.1 duplications cause BDCS. The BDCS duplications most likely lead to dysregulation of ARHGAP36. ARHGAP36 is a potential therapeutic target for both inherited and sporadic BCCs. What is already known about this topic? Bazex-Dupré-Christol syndrome (BDCS) is a rare X-linked basal cell carcinoma susceptibility syndrome linked to an 11·4-Mb interval on chromosome Xq25-q27.1. Loss-of-function variants in ACTRT1 and its regulatory elements were suggested to cause BDCS. What does this study add? BDCS is caused by small tandem noncoding intergenic duplications at chromosome Xq26.1. The Xq26.1 BDCS duplications likely dysregulate ARHGAP36, the flanking centromeric gene. ACTRT1 loss-of-function variants are unlikely to cause BDCS. What is the translational message? This study provides the basis for accurate genetic testing for BDCS, which will aid precise diagnosis and appropriate surveillance and clinical management. ARHGAP36 may be a novel therapeutic target for all forms of sporadic basal cell carcinomas.

Direct Comparison of Real-world Effectiveness of Biologics for Psoriasis using Absolute and Relative Psoriasis Area and Severity Index Scores in a Prospective Multicentre Cohort.

Real-world evidence, directly comparing the effectiveness of interleukin (IL)17-inhibitors, IL23-inhibitors, tumour necrosis factor alpha (TNF-α)-inhibitors and an IL12/23-inhibitor in psoriasis, is scarce. The aim of this study was to directly compare the first-year effectiveness of biologic therapies for psoriasis, corrected for confounders. This prospective, multicentre cohort study assessed BioCAPTURE data on etanercept, adalimumab, ustekinumab, secukinumab, ixekizumab, and guselkumab in 1,080 treatment episodes of 700 patients with psoriasis. The course of the mean absolute Psoriasis Area and Severity Index (PASI) and the proportion of patients who achieved PASI90/PASI75 were compared using linear mixed models and mixed logistic regression models respectively, corrected for baseline PASI, biologic naivety, and weight. Patients treated with adalimumab, ustekinumab, secukinumab, ixekizumab, or guselkumab all had a significantly lower mean PASI after 12 months compared with etanercept, and significantly higher overall odds of reaching PASI90 than those treated with etanercept. Patients treated with ixekizumab or guselkumab also had higher probabilities of reaching PASI90 than adalimumab, ustekinumab, and secukinumab. Relative to randomized controlled trials, the proportions of patients who reached PASI90/75 were lower in this real-world study.

Phenotype variability in tumor disorders of the skin appendages associated with mutations in the CYLD gene.

Mutations in the tumor suppressor gene CYLD underlie phenotypically heterogeneous hereditary tumor disorders of the skin appendages. These diseases are inherited autosomal dominantly and include Brooke-Spiegler syndrome (BSS; OMIM 605041), familial cylindromatosis (FC; OMIM 132700) and multiple familial trichoepithelioma (MFT; OMIM 601606). Clinically, cylindromas, trichoepitheliomas and spiradenomas can be found in affected individuals. We sought to elucidate the molecular genetic basis in individuals with newly diagnosed cylindromas, trichoepitheliomas and/or spiradenomas. Mutation analysis using polymerase chain reaction (PCR)-based techniques was performed in seven German patients and one Turkish patient. We detected two missense, two nonsense, two deletions and two duplication mutations in the CYLD gene, of which seven have not yet been reported. No genotype-phenotype correlation was detected amongst the patients. Our data provide additional information on the clinical and molecular genetic heterogeneity of disorders associated with CYLD mutations.

A novel therapeutic strategy for turban tumor: scalp excision and combined reconstruction with artificial dermis and split skin graft.

BACKGROUND: Brooke-Spiegler syndrome is a hereditary tumor predisposition disorder characterized by the development of cylindromas, trichoepitheliomas, and spiradenomas. Predilection sites of the disease are hair follicles and sweat glands of the head and neck. In some patients, the tumors can coalesce to so-called turban tumors, which then usually cause cosmetic, psychological, and functional impairment. A curative therapy is not yet available, and thus total scalp excision followed by split skin graft is evolving as a frequently applied therapy. However, this treatment can lead to the formation of a thin and vulnerable skin, which hampers wearing a wig. Therefore, a more robust and functional solution is preferable. Here, we report on a woman with a turban tumor who suffered enormously from the disease and had secluded herself from social life. METHODS: We treated her with a total scalp excision down to the periosteum, followed by sequential combined reconstruction with an artificial dermal template and split skin grafts. RESULTS: The treatment resulted in formation of a robust and flexible skin. CONCLUSION: Treatment of turban tumor is a challenge considering the localization and extensiveness of the tumor masses. This novel therapy for turban tumor leads to a very good cosmetic and functional outcome.

[A boy with small lumps on his shoulder]. / Een jongen met bultjes op zijn schouder.

A 17-year-old boy presented with small papules on his right shoulder and was diagnosed with syringocystadenoma papilliferum.

Basal cell carcinoma and trichoepithelioma: a possible matter of confusion.

Difficulty in differentiation between a solitary basal cell carcinoma, which is known as a malign skin lesion and a benign trichoepithelioma, is a frequent problem in all day dermatologic practice. Clinically as well as histopathologically there are a lot of resemblances between these skin tumors. By means of two real life cases, we give here an overview of the possible problems and appliances in distinguishing these two entities; at the end we do some recommendation about the policy.

Brooke-Spiegler syndrome complicated by unilateral hearing loss.

Brooke-Spiegler syndrome is an autosomal dominant tumor predisposition disorder. The disease is characterized by the occurrence of multiple skin appendage tumors, including cylindroma, trichoepithelioma, and spiradenoma. In some patients, tumors cover the entire head circumference, thereby causing disfigurement and other complications. Here, we report on a man with multiple cylindroma that were distributed in a turban tumor-like fashion. One of these neoplasms arose in the meatus externus of the right ear leading to unilateral hearing loss, a complication that has been documented only on few occasions in this disease.