Consanguinity and Double Recessive Gene Pathology: Cutis Laxa (PYCR1) and Nephrotic Syndrome (PLCE1)

Clinical and molecular diagnosis of genodermatoses: Review and perspectives

Genodermatoses are a complex and heterogeneous group of genetic skin disorders characterized by variable expression and clinical and genetic heterogeneity, rendering their diagnosis challenging. DNA-based techniques, like whole-exome sequencing, can establish a diagnosis in 50% of cases. RNA-sequencing is emerging as an attractive tool that can obtain information regarding gene expression while integrating functional genomic data with regard to the interpretation of variants. This increases the diagnostic rate by an additional 10-15%. In the present review, we detail the clinical steps involved in the diagnosis of genodermatoses, as well as the current DNA-based technologies available to clinicians. Herein, the intention is to facilitate a better understanding of the possibilities and limitations of these diagnostic technologies. In addition, this review could guide dermatologists through new emerging techniques, such as RNA-sequencing and its applications to familiarizing them with future techniques. Currently, this multi-omics approach is likely the best strategy designed to promote the diagnosis of patients with genodermatoses and discover new skin disease genes that could result in novel targeted therapies.

Shikonin induces apoptosis and autophagy via downregulation of pyrroline-5-carboxylate reductase1 in hepatocellular carcinoma cells

Shikonin(SK) is a natural small molecule naphthoquinone compound, which has anti-cancer activity in various human malignant tumors. Pyrroline-5-carboxylate reductase 1(PYCR1) is involved in tumorigenesis and regulates various cellular processes, including growth, invasion, migration, and apoptosis. However, the effect of SK and PYCR1 on apoptosis and autophagy in hepatocellular carcinoma are unclear. Our goal is to determine the internal molecular mechanism of the interaction between SK and PYCR1 and its role in the occurrence and development of liver cancer. The CCK8 assay, wound healing assay, and transwell assays show that SK and siPYCR1(gene silence PYCR1) inhibited the malignant phenotype of HCC cells, including cell viability, colony formation, migration, and invasion, respectively. The flow cytometry assays and immunofluorescence show that SK and siPYCR1 activated apoptosis and autophagy, respectively. SK induces apoptosis and autophagy in a dose-dependent manner. In addition, HCC cells were transfected with small interference fragment PYCR1 siRNA to construct siPYCR1 and SK single treatment group and co-treatment group to verify the interaction between SK and PYCR1. The Western blot identified that PI3K/Akt/mTOR signal pathway protein expression was significantly downregulated in HCC cells treated with SK and siPYCR1 together. Collectively, SK may induce apoptosis and autophagy by reducing the expression of PYCR1 and suppressing PI3K/Akt/mTOR. Thus, SK may be a promising antineoplastic drug in Hepatocellular carcinoma (HCC). SK downregulating PYCR1 might supply a theoretical foundation for the potential therapeutic application in hepatocellular carcinoma.

New and Emerging Systemic Treatments for Atopic Dermatitis

Atopic dermatitis (AD) is a prevalent inflammatory skin condition that, depending on its severity, can cause enormous morbidity. Corticosteroids and systemic immunosuppression, traditionally standard of care for difficult-to-treat disease, have many undesirable side effects. The desire for targeted treatments along with an improved understanding of the pathophysiology of AD has spurred the development of novel treatments. In this article, we review promising new treatments and discuss how their targets—IL-13, IL-31, OX40 (CD134), and the Janus kinase family of proteins—participate in the pathogenesis of AD. We review the published phase II and III data for dupilumab, tralokinumab, lebrikizumab, nemolizumab, anti-OX40 antibody, baricitinib, abrocitinib, and upadacitinib. The introduction of new agents may offer new options, but it remains to be seen how narrow-acting agents, like single interleukin inhibitors, will compare in safety and efficacy to broad-acting agents such as JAK inhibitors.

Homozygous deletion of MYADML2 in cranial asymmetry, reduced bone maturation, multiple dislocations, lumbar lordosis, and prominent clavicles

A null mutation in a patient can facilitate phenotype assignment and uncovers the function of that specific gene. We present five sibs of a consanguineous Pakistani family afflicted with a new syndrome with an unusual combination of skeletal anomalies including cranial asymmetry, fused sagittal sutures deviating from the medial axis, mandibular prognathia, maxillary hypoplasia, misaligned and crowded teeth, delayed bone age, multiple dislocations, hypoplastic and malpositioned patellae, humeral intracondylar fissures, scapular dyskinesis, long limbs, lumbar lordosis, protruding chest, prominent clavicles, short 5th digital rays, and ventral transverse digital creases plus features of cutis laxa. We mapped the disease gene locus to a 3.62-Mb region at 17q25.3 and identified a homozygous deletion of maximal 7.3 kb deduced to totally inactivate MYADML2 and downstream gene PYCR1, biallelic variants in which cause autosomal recessive cutis laxa (ARCL). All five affected sibs had the most common features of ARCL but not many of the less common ones. We attributed the anomalies not typical for ARCL to MYADML2 deficit, because no other genetic defect possibly a candidate to underlie the skeletal phenotype was found. MYADML2 is a gene of unknown function, has not been studied, and has not been associated with disease. Our findings present a possible phenotype for MYADML2 deficit that includes impaired bone patterning and maturation, definitely show that the gene is not essential for survival, and provide a start point for future studies on the function of MYADML2 protein. Detection of new patients is needed to confirm and delineate MYADML2-deficiency phenotype.

A decade of next-generation sequencing in genodermatoses: the impact on gene discovery and clinical diagnostics

BACKGROUND

Discovering the genetic basis of inherited skin diseases is fundamental to improving diagnostic accuracy and genetic counselling. In the 1990s and 2000s, genetic linkage and candidate gene approaches led to the molecular characterization of several dozen genodermatoses, but over the past decade the advent of next-generation sequencing (NGS) technologies has accelerated diagnostic discovery and precision.

OBJECTIVES

This review examines the application of NGS technologies from 2009 to 2019 that have (i) led to the initial discovery of gene mutations in known or new genodermatoses and (ii) identified involvement of more than one contributing pathogenic gene in individuals with complex Mendelian skin disorder phenotypes.

METHODS

A comprehensive review of the PubMed database and dermatology conference abstracts was undertaken between January 2009 and December 2019. The results were collated and cross-referenced with OMIM.

RESULTS

We identified 166 new disease-gene associations in inherited skin diseases discovered by NGS. Of these, 131 were previously recognized, while 35 were brand new disorders. Eighty-five were autosomal dominant (with 43 of 85 mutations occurring de novo), 78 were autosomal recessive and three were X-linked. We also identified 63 cases harbouring multiple pathogenic mutations, either involving two coexisting genodermatoses (n = 13) or an inherited skin disorder in conjunction with other organ system phenotypes (n = 50).

CONCLUSIONS

NGS technologies have accelerated disease-gene discoveries in dermatology over the last decade. Moreover, the era of NGS has enabled clinicians to split complex Mendelian phenotypes into separate diseases. These genetic data improve diagnostic precision and make feasible accurate prenatal testing and better-targeted translational research.