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Background: Yellow nail syndrome (YNS) is a rare disorder characterized by a triad of yellow dystrophic nails, lymphedema, and chronic lung disease. Most patients present in adulthood, with only a few congenital or familial cases described. The cause of YNS remains largely unknown, although defects in lymphatic vessel development are suggested to play a significant role., Objective: To elucidate the genetic mechanisms underlying YNS., Design: Analysis of genetic sequencing data and gene and protein expression studies., Setting: A tertiary care academic medical center., Patients: 6 patients with congenital YNS (cYNS) and 5 with sporadic YNS (sYNS)., Measurements: Exome and genome sequencing were used to detect disease-causing variants, complemented by RNA analyses for intronic variants. Protein and gene expressions were studied by immunofluorescence staining and real-time reverse transcriptase quantitative polymerase chain reaction analyses., Results: Biallelic variants in CELSR1 ( n  = 5) or likely FZD6 ( n  = 1), both core molecules in the Wnt/planar cell polarity (PCP) pathway, were identified in all patients with cYNS; none of the patients with sYNS had candidate genetic variants. Immunofluorescence staining showed that CELSR1 colocalizes with lymphatic vessels in the skin but not in the lungs or the intestine. Moreover, levels of CELSR1 and FZD6 proteins were negligible to zero in patient tissues ( n  = 2) compared with control tissues. Gene expression of Wnt/PCP-related genes was reduced in patients with cYNS ( n = 3), and patients with sYNS ( n  = 4) showed milder gene expression impairments., Limitation: Small cohort size and limited sample availability., Conclusion: Defects in PCP organization may play a major role in the pathogenesis of YNS. To the authors' knowledge, this is the first demonstration of a mechanism explaining YNS development, mainly in its congenital form but also in patients with sporadic disease., Primary Funding Source: The Prof. Baum Research Fund of Israel Lung Association., Competing Interests: Disclosures: Disclosure forms are available with the article online.

Brain tumors comprise over 100 types of masses, differing in the following: location; patient age; molecular, histological, and immunohistochemical characteristics; and prognosis and treatment. Glioma tumors originate from neuroglia, cells supporting the brain. Palladin, a structural protein widely expressed in mammalian tissues, has a pivotal role in cytoskeletal dynamics and motility in health and disease. Palladin is linked to the progression of breast, pancreatic, and renal cancers. In the central nervous system, palladin is involved in embryonic development, neuronal maturation, the cell cycle, differentiation, and apoptosis. However, the role of palladin in brain tumors is unknown. In this work, we explored palladin's role in glioma. We analyzed clinical data, along with bulk and single-cell gene expression. We then validated our results using IHC staining of tumor samples, together with qRT-PCR of glioma cell lines. We determined that wild-type palladin-4 is overexpressed in adult gliomas and is correlated with a decrease in survival. Palladin expression outperformed clinically used prognostic markers and was most prominent in glioblastoma. Finally, we showed that palladin originates from the malignant cell population. Our findings indicate that palladin expression might be linked to adult glioma progression and is associated with prognosis., Competing Interests: The authors declare no conflict of interest.