An atypical case of incontinentia pigmenti with a hypomorphic variant.

Incontinentia pigmenti (IP) is a rare X-linked dominant genodermatosis that affects skin, hair, teeth, eyes and central nervous system. We present the case of a female patient with mild IP caused by a hypomorphic pathogenic variant of the inhibitor of the kappa light polypeptide gene enhancer in B cells, kinase gamma (IKBKG) gene. This is the first report of a female IP patient with the hypomorphic variant, NM_001099856.6: c.1423dup, which is causative of anhidrotic ectodermal dysplasia with immune deficiency in males.

Proprotein Convertase Furin Regulates Melanogenesis via the Notch Signaling Pathway.

BACKGROUND: Furin is a calcium-dependent serine protease found in almost all mammals. It plays an important role in embryogenesis, tissue homeostasis, tumors pathogenesis, viral infectious diseases, and neurodegenerative diseases. However, whether furin directly regulates melanin synthesis and transport has rarely been evaluated yet. The present study aimed to investigate furin potential function and mechanisms in melanogenesis. METHODS: Short hairpin RNAs targeting furin gene (sh-furin RNAs) were used to inhibit furin gene expression in human melanoma cell line MNT-1 cells. Then, intracellular melanin content was measured using a sodium hydroxide method. Extracellular melanin content was measured determining cell culture medium absorbance at 450 nm. Levodopa (L-DOPA) oxidation rate was measured to assess the tyrosinase activity. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting (WB) were performed to measure melanogenesis-related genes and Notch pathway-related genes expression levels. Human primary melanocytes (MCs) were extracted from foreskin tissues and were stimulated with a furin inhibitor. Then, the extracellular and intracellular melanin content, tyrosinase activity and molecules related to melanogenesis and the Notch pathway expression were measured in MCs with or without a furin inhibitor. Additionally, morpholino technology was used to inhibit furin in zebrafish. Zebrafish pigmentary phenotypes in the control group and furin inhibition group were observed with a stereo microscope. Then, MCs number in the tail and head of the zebrafish were counted using Image J software (version 1.53t, National Institute of Health, Bethesda, MD, USA). Meanwhile, melanin content, tyrosinase activity, and molecules related to melanogenesis and the Notch pathway expression levels were measured. Subsequently, valproic acid (VPA), a Notch pathway agonist, was used in MNT-1 melanoma cells treated with or without sh-furin lentiviral vectors for rescue experiments. RESULTS: Furin inhibition enhanced intracellular and extracellular melanin content, and cellular tyrosinase activity in MNT-1 cells and MCs. Additionally, furin inhibition increased melanin synthesis-associated and transport-associated proteins expression levels while inhibiting Notch pathway-relevant proteins. After using VPA to activate the Notch pathway in MNT-1 cells transfected with a sh-furin RNA, the biological effects resulting from furin knockdown were reversed. In addition, the results of in vivo experiments using morpholino to knock down furin gene in zebrafish further confirmed that furin knockdown regulated melanogenesis and impaired the Notch pathway. CONCLUSIONS: This study clarified that furin affected the synthesis and transport of melanin via Notch pathway. Notch pathway may be a potential therapeutic target for pigmented skin diseases.

KRT5 mutation regulate melanin metabolism through notch signalling pathway between keratinocytes and melanocytes.

Dowling-Degos disease (DDD) is an autosomal dominant hereditary skin disease characterized by acquired reticular hyperpigmentation in flexural sites, and one of its causative genes is KRT5 gene. But the effect of KRT5, expressed only in keratinocytes, on melanocytes is unclear. Other pathogenic genes of DDD include POFUT1, POGLUT1 and PSENEN genes, which is involved in posttranslational modification of Notch receptor. In this study, we aim to determine the ablation of keratinocyte KRT5 affect melanogenesis in melanocyte through Notch signalling pathway. Here we found that KRT5 downregulation decreased the expression of the Notch ligand in keratinocytes and Notch1 intracellular domain in melanocytes, by establishing two cell models of ablation of KRT5 in keratinocytes based on CRISPR/Cas9 site-directed mutation and lentivirus-mediated shRNA. Treatment of melanocytes with Notch inhibitors had same effects with ablation of KRT5 on increase of TYR and decrease of Fascin1. Activation of Notch signalling reverses the effect of ablation of KRT5 on melanogenesis. Immunohistochemistry of DDD lesions with KRT5 gene mutation confirmed changes in the expression of relevant molecules in Notch signalling. Our research elucidates molecular mechanism of KRT5-Notch signalling pathway in the regulation of melanocytes by keratinocytes, and preliminary reveal the mechanism of DDD pigment abnormality caused by KRT5 mutation. These findings identify potential therapeutic targets of the Notch signalling pathway for the treatment of skin pigment disorders.

Acquired latent tuberculosis infection in psoriasis patients treated with etanercept in the People's Republic of China.

BACKGROUND: TNF-α plays a key role in host defense against mycobacterial infection, and patients receiving TNF-α blocker treatment have increased susceptibility to tuberculosis disease. In the People's Republic of China, an intermediate tuberculosis-burden country, the latent tuberculosis infection (LTBI) risk in patients with psoriasis who are treated with etanercept, the safest kind of TNF-α blocker, is unknown. OBJECTIVES: This study reports the LTBI risk in patients with psoriasis after etanercept treatment and aims to answer the question of how often rescreening for LTBI should be done in order to reduce active tuberculosis infection of patients and further reduce the incidence of active tuberculosis disease. PATIENTS AND METHODS: This retrospective review evaluated patients with moderate-to-severe chronic plaque psoriasis between 2009 and 2013. All patients were excluded tuberculosis infection and received etanercept 25 mg twice weekly, then the patients were checked for LTBI 3 months after etanercept treatment to observe the incidence of LTBI and assess the need for rescreening for LTBI every 3 months. RESULTS: We retrospectively analyzed 192 patients with psoriasis with moderate-to-severe chronic plaque whose tuberculin skin test and chest X-rays were negative and who received etanercept 25 mg twice weekly. Eighteen of them were excluded because they received less than 3 months of etanercept therapy. After treatment with etanercept, four patients were found to have LTBI. CONCLUSION: In this study, the incidence of LTBI after 3 months was four in 192 (2.1%), which is higher than the annual incidence of LTBI in the People's Republic of China (0.72%), so LTBI could be expected to occur within 3 months in psoriasis patients on etanercept. Periodic screening for LTBI in the therapy course, as well as before initiating treatment, is necessary in those patients who use a TNF-α blocker. We recommend rescreening for LTBI every 3 months.

A novel missense KIT mutation causing piebaldism in one Chinese family associated with café-au-lait macules and intertriginous freckling.

Piebaldism is a rare autosomal dominant genodermatosis, manifesting as congenital and stable depigmentation of the skin and white forelock. It has been found to be associated with mutations in the KIT or SLUG genes. We report a Chinese piebaldism family including a 28-year-old woman and her 3-year-old son with characteristics of white patches and forelock associated with numerous brown macules and patches. Genomic DNA samples of the proband and her son were extracted from their peripheral blood. One hundred unrelated healthy individuals were used as controls. All coding regions of KIT, SLUG, and NF1 genes were amplified by polymerase chain reaction using exon flanking intronic primers and Sanger sequencings were performed. DNA sequencing revealed heterozygous missense c.2431T>G mutation in exon 17 of the KIT gene in the proband and the affected son. No potentially pathogenic variant was identified in SLUG or NF1 genes. The nucleotide substitution was not found in 100 unrelated control individuals. This study reveals a novel KIT mutation in piebaldism, and it further supports that café-au-lait macules and intertriginous freckling of piebaldism are parts of pigmented anomaly in piebaldism, which does not necessarily represent coexistence of neurofibromatosis type 1 (NF1).

Patchy alopecia areata sparing gray hairs: a case series.

Alopecia areata is an unpredictable, non-scarring hair loss condition. Patchy alopecia areata sparing gray hairs is rare. Here we present 4 cases with patchy non-scarring hair loss, which attacked pigmented hairs only and spared gray hairs. It should be differentiated from vitiligo, colocalization of vitiligo and alopecia areata, and depigmented hair regrowth after alopecia areata.