ABSTRACT
Netherton syndrome (NS) is a rare genodermatosis with an autosomal recessive pattern of inheritance caused by pathogenic variants in the SPINK5 gene. It is characterized by a triad consisting of atopic diathesis, ichthyosis linearis circumflexa, and hair shaft abnormalities. Ichthyosis linearis circumflexa can be confused with atopic dermatitis leading to a delayed diagnosis. Furthermore, difficulty in making the differential diagnosis with other atopiform, erythrodermic, and ichthyosiform entities that exhibit hair shaft abnormalities represent a challenge. Trichoscopy is an accessible and noninvasive auxiliary diagnostic tool in these cases; the hair shaft abnormalities found in NS are bamboo, golf tee, and matchstick hairs. Identification of a pathogenic variant in the SPINK5 gene through genetic testing is necessary to confirm the diagnosis. Multiple treatment options are available including topical therapy with emollients, corticosteroids, calcineurin inhibitors, antiseptics, and narrowband UVB phototherapy. Systemic treatments comprehend intravenous immunoglobulins, and advances in the understanding of the pathophysiology of NS have led to more directed therapies with biologics such as infliximab, ixekizumab, secukinumab, ustekinumab, and dupilumab. Treatments currently under investigation include inhibitors of kallikrein 5, cathelicidins, drugs activating the transcription factor nuclear factor erythroid-derived 2-like 2, and gene therapy using autologous keratinocytes induced with a lentiviral vector encoding SPINK5.
ABSTRACT
The connection between Netherton syndrome and overactivation of epidermal/dermal proteases, particularly Kallikrein 5 (KLK5) has been well established and it is expected that a KLK5 inhibitor would improve the dermal barrier and also reduce the pain and itch that afflict Netherton syndrome patients. One of the challenges of covalent protease inhibitors has been achieving selectivity over closely related targets. In this paper we describe the use of structural insight to design and develop a selective and highly potent reversibly covalent KLK5 inhibitor from an initial weakly binding fragment.
Subject(s)
Benzamidines/chemistry , Kallikreins/antagonists & inhibitors , Netherton Syndrome/drug therapy , Serine Proteinase Inhibitors/chemistry , Amino Acid Sequence , Benzamidines/pharmacology , Binding Sites , Drug Evaluation, Preclinical , Humans , Isomerism , Models, Molecular , Molecular Structure , Mutation , Protein Binding , Serine Peptidase Inhibitor Kazal-Type 5/genetics , Serine Proteinase Inhibitors/pharmacology , Structure-Activity RelationshipABSTRACT
Syndromic ichthyosis is rare inherited disorders of cornification with varied disease complications. This disorder appears in seventeen subtypes associated with severe systematic manifestations along with medical, cosmetic and social problems. Syndromic ichthyosis with prominent hair abnormalities covers five major subtypes: Netherton syndrome, trichothiodystrophy, ichthyosis hypotrichosis syndrome, ichthyosis hypotrichosis sclerosing cholangitis and ichthyosis follicularis atrichia photophobia syndrome. These syndromes mostly prevail in high consanguinity states, with distinctive clinical features. The known pathogenic molecules involved in ichthyosis syndromes with prominent hair abnormalities include SPINK5, ERCC2, ERCC3, GTF2H5, MPLKIP, ST14, CLDN1 and MBTPS2. Despite underlying genetic origin, most of the health professionals solely rely on phenotypic expression of these disorders that leads to improper management of patients, hence making these patients living an orphanage life. After dermal features, association of other systems such as nervous system, skeletal system, hair abnormalities or liver problems may sometimes give clues for diagnosis but still leaving place for molecular screening for efficient diagnosis. In this paper, we have presented a review of ichthyosis syndrome with prominent hair abnormalities, with special emphasis on their updated genetic consequences and disease management. Additionally, we aim to update health professionals about the practice of molecular screening in ichthyosis syndromes for appropriate diagnosis and treatment.
Subject(s)
Hair Diseases/therapy , Hair/abnormalities , Ichthyosis/therapy , Photophobia/therapy , Rare Diseases/therapy , Consanguinity , Dermatologic Agents/therapeutic use , Exome/genetics , Genetic Testing/methods , Hair Diseases/diagnosis , Hair Diseases/etiology , Hair Diseases/mortality , High-Throughput Nucleotide Sequencing , Humans , Ichthyosis/diagnosis , Ichthyosis/etiology , Ichthyosis/mortality , Mutation , Phenotype , Photophobia/diagnosis , Photophobia/etiology , Photophobia/mortality , Phototherapy/methods , Rare Diseases/diagnosis , Rare Diseases/etiology , Rare Diseases/mortality , SyndromeABSTRACT
BACKGROUND: Ichthyosis linearis circumflexa is a rare form of ichthyosis characterized by polycyclic and annular lesions which are bordered by a double-edged scale. Netherton syndrome is a genodermatosis in which ichthyosis linearis circumflexa is accompanied by characteristic hair shaft abnormalities and atopic diathesis. Different treatment modalities such as emmolients, keratolytics, calcipotriene, topical corticosteroids, topical calcineurin inhibitors, systemic retinoids, phototherapy and photochemotherapy have been used with variable results. Topical therapies may result in considerable absorption because of the defective barrier function in ichthyosis linearis circumflexa/Netherton syndrome. MAIN OBSERVATION: A 12-year-old patient diagnosed as ichthyosis linearis circumflexa demonstrated considerable improvement with narrowband UVB phototherapy at the end of 30 sessions. CONCLUSION: Short-term narrowband-UVB may an effective treatment option in patients with ichthyosis linearis circumflexa/Netherton syndrome.