Splicing mutation in MVK is a cause of porokeratosis of Mibelli

Porokeratosis of Mibelli Treated With Topical 2% Lovastatin/2% Cholesterol Ointment

Porokeratosis is characterized by disruptions in the isoprenoid pathway, leading to the development of cornoid lamella, a unique skin lesion consisting of parakeratotic cells. The condition has a genetic foundation involving mutations affecting cholesterol synthesis, and new treatments aim to address these metabolic disruptions. This study examines a 56-year-old male with porokeratosis of Mibelli (PM) who presented with a non-healing erosion on his finger that persisted for two years. Previous therapies, including corticosteroids, antibiotics, and tacrolimus, proved ineffective. The patient then received a novel treatment with a topical 2% lovastatin/2% cholesterol ointment. After nine months, there was significant clinical improvement; the lesion was markedly reduced in size and appearance. This case underscores the potential of lovastatin/cholesterol ointment as an effective treatment for PM, indicating its promise for broader therapeutic applications.

Porokeratoses-A Comprehensive Review on the Genetics and Metabolomics, Imaging Methods and Management of Common Clinical Variants

Porokeratosis is a heterogeneous group of keratinising disorders characterised by the presence of particular microscopic structural changes, namely the presence of the cornoid lamella. This structure develops as a consequence of a defective isoprenoid pathway, critical for cholesterol synthesis. Commonly recognised variants include disseminated superficial actinic porokeratosis, disseminated superficial porokeratosis, porokeratosis of Mibelli, palmoplantar porokeratosis (including porokeratosis palmaris et plantaris disseminata and punctate porokeratosis), linear porokeratosis, verrucous porokeratosis (also known as genitogluteal porokeratosis), follicular porokeratosis and porokeratoma. Apart from the clinical presentation and epidemiology of each variant listed, this review aims at providing up-to-date information on the precise genetic background, introduces imaging methods facilitating the diagnosis (conventional and ultraviolet-induced fluorescence dermatoscopy, reflectance confocal microscopy and pathology), discusses their oncogenic potential and reviews the literature data on the efficacy of the treatment used, including the drugs directly targeting the isoprenoid-mevalonate pathway.

Explore the role of long noncoding RNAs and mRNAs in intracranial atherosclerotic stenosis: From the perspective of neutrophils

CONTEXT

Circulating neutrophils and long noncoding RNAs (lncRNAs) play various roles in intracranial atherosclerotic stenosis (ICAS).

OBJECTIVE

Our study aimed to detect differentially expressed (DE) lncRNAs and mRNAs in circulating neutrophils and explore the pathogenesis of atherosclerosis from the perspective of neutrophils.

METHODS

Nineteen patients with ICAS and 15 healthy controls were enrolled. The peripheral blood of the participants was collected, and neutrophils were separated. The expression profiles of lncRNAs and mRNAs in neutrophils from five patients and five healthy controls were obtained, and DE lncRNAs and mRNAs were selected. Six lncRNAs were selected and validated using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and ceRNA and lncRNA-RNA binding protein (RBP)-mRNA networks were constructed. Correlation analysis between lncRNAs and mRNAs was performed. Functional enrichment annotations were also performed.

RESULTS

Volcano plots and heat maps displayed the expression profiles and DE lncRNAs and mRNAs, respectively. The qRT-PCR results revealed that the four lncRNAs showed a tendency consistent with the expression profile, with statistical significance. The ceRNA network revealed three pairs of regulatory networks: lncRNA RP3-406A7.3-NAGLU, lncRNA HOTAIRM1-MVK/IL-25/GBF1/CNOT4/ANKK1/PLEKHG6, and lncRNA RP11-701H16.4-ZNF416. The lncRNA-RBP-mRNA network showed five pairs of regulatory networks: lncRNA RP11-701H16.4-TEK, lncRNA RP11-701H16.4-MED17, lncRNA SNHG19-NADH-ubiquinone oxidoreductase core subunit V1, lncRNA RP3-406A7.3-Angel1, and lncRNA HOTAIRM1-CARD16.

CONCLUSIONS

Our study identified and verified four lncRNAs in neutrophils derived from peripheral blood, which may explain the transcriptional alteration of neutrophils during the pathophysiological process of ICAS. Our results provide insights for research related to the pathogenic mechanisms and drug design of ICAS.

Spectrum of clinical features and genetic variants in mevalonate kinase (MVK) gene of South Indian families suffering from Hyperimmunoglobulin D Syndrome

Hyper-IgD syndrome (HIDS, OMIM #260920) is a rare autosomal recessive autoinflammatory disorder caused by pathogenic variants in the mevalonate kinase (MVK) gene. HIDS has an incidence of 1:50,000 to 1:5,000, and is thought to be prevalent mainly in northern Europe. Here, we report a case series of HIDS from India, which includes ten patients from six families who presented with a wide spectrum of clinical features such as recurrent fever, oral ulcers, rash, arthritis, recurrent diarrhea, hepatosplenomegaly, and high immunoglobulin levels. Using whole exome sequencing (WES) and/or Sanger capillary sequencing, we identified five distinct genetic variants in the MVK gene from nine patients belonging to six families. The variants were classified as pathogenic or likely pathogenic as per the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG-AMP) guidelines for annotation of sequence variants. Over 70% of patients in the present study had two recurrent mutations in MVK gene i.e. a nonsynonymous variant p.V377I, popularly known as the ‘Dutch mutation’, along with a splicing variant c.226+2delT in a compound heterozygous form. Identity by descent analysis in two patients with the recurrent variants identified a 6.7 MB long haplotype suggesting a founder effect in the South Indian population. Our analysis suggests that a limited number of variants account for the majority of the patients with HIDS in South India. This has implications in clinical diagnosis, as well as in the development of cost-effective approaches for genetic diagnosis and screening. To our best knowledge, this is the first and most comprehensive case series of clinically and genetically characterized patients with HIDS from India.

Identification of a novel mutation in the mechanoreceptor-encoding gene CXCR1 in patients with keloid

Keloids are skin fibroproliferative tumors characterized by locally invasive growth of fibroblasts and excessive collagen deposition. The objective of this study is to investigate the molecular basis of the keloid scar by studying the mutation of related genes. We performed gene screening of mechanoreceptors by quantitative polymerase chain reaction (qPCR), Sanger sequencing to detect the CXCR1gene mutation, and immuno-histochemistry to determine CXCR1 protein expression. Among the genes encoding mechanoreceptors, the expression of CXCR1 mRNA was significantly higher in keloid scar tissues than in the surrounding tissues of normal controls (P < 0.05). Sequencing analysis identified a novel missense mutation, c.574G > A (p.Gly192Glu). Immunohistochemistry showed heightened protein expression of CXCR1 in keloid scars as compared to controls. Our findings indicate that CXCR1 gene mutation and altered protein expression are associated with keloid scar development. Identification of the CXCR1 gene mutation might provide insights into the molecular mechanism underlying keloid scar and underscores the potential importance of mechanoreceptors in keloid scar pathogenesis.

Loss-of-function Mutation in PMVK Causes Autosomal Dominant Disseminated Superficial Porokeratosis

Disseminated superficial porokeratosis (DSP) is a rare keratinization disorder of the epidermis. It is characterized by keratotic lesions with an atrophic center encircled by a prominent peripheral ridge. We investigated the genetic basis of DSP in two five-generation Chinese families with members diagnosed with DSP. By whole-exome sequencing, we sequencing identified a nonsense variation c.412C > T (p.Arg138*) in the phosphomevalonate kinase gene (PMVK), which encodes a cytoplasmic enzyme catalyzing the conversion of mevalonate 5-phosphate to mevalonate 5-diphosphate in the mevalonate pathway. By co-segregation and haplotype analyses as well as exclusion testing of 500 normal control subjects, we demonstrated that this genetic variant was involved in the development of DSP in both families. We obtained further evidence from studies using HaCaT cells as models that this variant disturbed subcellular localization, expression and solubility of PMVK. We also observed apparent apoptosis in and under the cornoid lamella of PMVK-deficient lesional tissues, with incomplete differentiation of keratinocytes. Our findings suggest that PMVK is a potential novel gene involved in the pathogenesis of DSP and PMVK deficiency or abnormal keratinocyte apoptosis could lead to porokeratosis.

Genomic variations of the mevalonate pathway in porokeratosis

Porokeratosis (PK) is a heterogeneous group of keratinization disorders. No causal genes except MVK have been identified, even though the disease was linked to several genomic loci. Here, we performed massively parallel sequencing and exonic CNV screening of 12 isoprenoid genes in 134 index PK patients (61 familial and 73 sporadic) and identified causal mutations in three novel genes (PMVK, MVD, and FDPS) in addition to MVK in the mevalonate pathway. Allelic expression imbalance (AEI) assays were performed in 13 lesional tissues. At least one mutation in one of the four genes in the mevalonate pathway was found in 60 (98%) familial and 53 (73%) sporadic patients, which suggests that isoprenoid biosynthesis via the mevalonate pathway may play a role in the pathogenesis of PK. Significantly reduced expression of the wild allele was common in lesional tissues due to gene conversion or some other unknown mechanism. A G-to-A RNA editing was observed in one lesional tissue without AEI. In addition, we observed correlations between the mutations in the four mevalonate pathway genes and clinical manifestations in the PK patients, which might support a new and simplified classification of PK under the guidance of genetic testing.

DOI:http://dx.doi.org/10.7554/eLife.06322.001

Porokeratosis refers to a group of around twenty skin conditions that involve a build-up of a protein called keratin in skin cells. Keratin forms the tough fibres that give strength to hair and nails, and people suffering from porokeratosis develop hardened skin lesions. Porokeratosis is an uncommon condition; most cases are inherited and have been linked to exposure to ultraviolet light and having a weakened immune system.

Mutations in one gene called MVK are known to cause two forms of the disorder, but it is suspected that other genetic causes of porokeratosis will also be identified. The MVK gene encodes an enzyme that is involved in making chemicals called isoprenoids. This large and diverse class of chemicals provides the building blocks for making many other important molecules in all living species. Zhang, Li et al. have now analysed genetic material from 134 different porokeratosis patients to search for mutations in other genes involved in the production of isoprenoids. The patients examined include 61 people with a family history of the disorder, and 73 cases in which the condition seems to be a one-off occurrence.

This search identified mutations in three additional genes (called PMVK, MVD and FDPS) that are all linked to porokeratosis. Further analysis of these three genes and MVK revealed that about half of the patients with mutations in the MVK gene developed large lesions (that were over 5 centimetres in diameter). However, those with mutations in the other three genes did not develop such large lesions. Mutations in some of the newly identified genes were instead linked to porokeratosis affecting specific areas of the body; for example, PMVK and MVD mutations are linked to porokeratosis localized to the genitals and around the eyes, respectively. This means that, in the future, doctors might be able to simplify the diagnosis of the different varieties of porokeratosis based on information gained via genetic tests.

DOI:http://dx.doi.org/10.7554/eLife.06322.002

Hyper-IgD syndrome/mevalonate kinase deficiency: what is new?

Mevalonate kinase deficiency or hyper-IgD syndrome is a hereditary autoinflammatory syndrome caused by mutations in the mevalonate kinase gene. In this review, we will discuss new findings in this disorder that have been published in the last 2 years. This includes new insights into pathophysiology, treatment, and the clinical phenotype linked to the genetic defect.