{{Short description|A rare genetic disorder affecting the skin, hair, and immune system}}
| synonyms = Comèl-Netherton syndrome
{{Use dmy dates|date=October 2023}}
| name = Netherton syndrome
| image = Autosomal recessive - en.svg
| caption = Netherton syndrome has an autosomal recessive pattern of [[Heredity|inheritance]].
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'''Netherton syndrome''' is a severe, [[autosome|autosomal]] [[dominance (genetics)|recessive]]<ref name="ns05">{{cite journal |vauthors=Chao SC, Richard G, Lee JY |title=Netherton syndrome: report of two Taiwanese siblings with staphylococcal scalded skin syndrome and mutation of SPINK5 |journal=Br J Dermatol |volume=152 |issue=1 |pages=159–165 |year=2005 |pmid=15656819 |doi=10.1111/j.1365-2133.2005.06337.x }}</ref> form of [[ichthyosis]] associated with mutations in the ''[[SPINK5]]'' gene.<ref name="pmid10835624">{{cite journal |vauthors=Chavanas S, Bodemer C, Rochat A |title=Mutations in SPINK5, encoding a serine protease inhibitor, cause Netherton syndrome |journal=Nat. Genet. |volume=25 |issue=2 |pages=141–142 |date=June 2000 |pmid=10835624 |doi=10.1038/75977 |s2cid=40421711 }}</ref><ref name="Fitz2"/> It is named after Earl W. Netherton (1910–1985), an American dermatologist who discovered it in 1958.<ref>Netherton, E. W. A unique case of trichorrhexis nodosa: 'bamboo hairs.'. Arch. Derm. '''78''': 483-487, 1958.</ref>
==Signs and symptoms==
'''Netherton syndrome''' is a rare [[genetic disorder]] characterized by skin, hair, and immune system abnormalities. It is an [[autosomal recessive]] condition, meaning that an individual must inherit two copies of the defective gene, one from each parent, to be affected by the disorder.
Netherton syndrome is characterized by chronic skin inflammation, universal pruritus (itch), severe dehydration, and stunted growth. Patients with this disorder tend to have a hair shaft defect ([[trichorrhexis invaginata]]), also known as "bamboo hair". The disrupted skin barrier function in affected individuals also presents a high susceptibility to [[infection]] and [[allergy]], leading to the development of scaly, reddish skin similar to [[atopic dermatitis]].<ref name="descargues">
{{cite journal |vauthors=Descargues P, Deraison C, Bonnart C, Kreft M, Kishibe M, Ishida-Yamamoto A, Elias P, Barrandon Y, Zambruno G, Sonnenberg A, Hovnanian A | title = Spink5-deficient mice mimic Netherton syndrome through degradation of desmoglein 1 by epidermal protease hyperactivity. | journal = Nat Genet | volume = 37 | issue = 1 | pages = 56–65 | date = January 2005 | pmid = 15619623| pmc = | doi = 10.1038/ng1493 | s2cid = 11404025 }}</ref> In severe cases, these atopic manifestations persist throughout the individual's life, and consequently post-natal mortality rates are high. In less severe cases, this develops into the milder [[ichthyosis linearis circumflexa]].<ref name="Fitz2">Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). Page 496. McGraw-Hill. {{ISBN|0-07-138076-0}}.</ref>
Netherton syndrome has recently been characterised as a primary immunodeficiency, which straddles the innate and acquired immune system, much as does [[Wiskott–Aldrich syndrome]]. A group of Netherton patients have been demonstrated to have altered immunoglobulin levels (typically high IgE and low to normal IgG) and immature [[natural killer cells]]. These Natural Killer cells have a reduced lytic function; which can be improved with regular infusions of immunoglobulin (see 'Treatment'); although the mechanism for this is not clear.<ref name="Renner">{{cite journal |vauthors=Renner E, Hartle D, Rylaarsdam S, Young M, Monaco-Shawver L, Kleiner G, Markert ML, Stiehm ER, Belohradsky B, Upton M, Torgerson T, Orange J, Ochs H | title = Comel-Netherton syndrome defined as primary immunodeficiency. | journal = The Journal of Allergy and Clinical Immunology | volume = 124 | issue = 3 | pages = 536–543 | date = August 2009 | doi = 10.1016/j.jaci.2009.06.009 | pmid=19683336 | pmc=3685174}}</ref>
==Genetics==
[[File:Autosomal recessive - en.svg|thumb|right|Diagram of autosomal recessive inheritance]]
Netherton syndrome is caused by mutations in the [[SPINK5]] gene, which encodes the protein [[LEKTI]] (lympho-epithelial Kazal-type-related inhibitor). This protein plays a crucial role in skin barrier function and immune regulation. The disorder follows an [[autosomal recessive]] pattern of inheritance, as illustrated in the diagram.
Patients are more prone than healthy people to infections of all types, especially recurrent skin infections with staphylococcus. They may have more severe infections; but are not as vulnerable to opportunistic pathogens as patients with true Natural Killer cell deficiency-type SCID.
==Clinical Features==
The clinical presentation of Netherton syndrome is highly variable but typically includes the following features:
== Cause ==
===Skin Abnormalities===
Patients often present with [[ichthyosis linearis circumflexa]], a condition characterized by red, scaly skin with a distinctive double-edged scale. [[Atopic dermatitis]]-like symptoms are also common, leading to chronic skin inflammation and irritation.
Netherton syndrome is an autosomal [[recessive]] disorder associated with mutations in the ''SPINK5'' gene, which encodes the [[serine protease]] inhibitor lympho-epithelial Kazal-type-related inhibitor ([[LEKTI]]).<ref name="pmid10835624"/> These mutations result in a dysfunctional protein that has a reduced capacity to inhibit serine proteases expressed in the skin. Potential endogenous targets of LEKTI include [[KLK5]], [[KLK7]] and [[KLK14]].<ref name="Ovaere2009">
===Hair Abnormalities===
{{cite journal |vauthors=Ovaere P, Lippens S, Vandenabeele P, Declercq W | title = The emerging roles of serine protease cascades in the epidermis | journal = Trends Biochem Sci | volume = 34 | issue = 9 | pages = 453–63 | date = August 2009 | pmid = 19726197 | pmc = | doi =10.1016/j.tibs.2009.08.001 }}
A hallmark of Netherton syndrome is [[trichorrhexis invaginata]], also known as "bamboo hair," where the hair shaft is fragile and prone to breakage. This can lead to sparse and brittle hair.
</ref> These enzymes are involved in various aspects of epidermal remodelling, including [[desquamation]], [[PAR-2]] activation and degradation of lipid hydrolases, suggesting a potential mechanism for the development of atopic manifestations characteristic of Netherton syndrome.<ref name="pmid16601670">
{{cite journal |vauthors=Hachem JP, Wagberg F, Schmuth M, Crumrine D, Lissens W, Jayakumar A, Houben E, Mauro TM, Leonardsson G, Brattsand M, Egelrud T, Roseeuw D, Clayman GL, Feingold KR, Williams ML, Elias PM |title=Serine protease activity and residual LEKTI expression determine phenotype in Netherton syndrome |journal=J Invest Dermatol |volume=126 |issue=7 |pages=1609–21 |date=April 2006 |pmid=16601670 |doi= 10.1038/sj.jid.5700288}}
</ref>
Disease severity is determined by the level of LEKTI expression and, consequently, serine protease activity. Complete SPINK5 gene deletions have been linked to severe cases, while mutations which induce [[alternate splicing]] or create [[premature stop codon]]s may lead to varying levels of severity.<ref name="pmid16601670" /> Furthermore, LEKTI-knockout mice exhibit a phenotype similar to Netherton syndrome in humans.<ref name="descargues" />
===Immune System Abnormalities===
Individuals with Netherton syndrome may experience recurrent infections due to an impaired immune response. They are also at increased risk for [[atopy]], including [[asthma]], [[allergic rhinitis]], and [[food allergies]].
==Diagnosis==
==Diagnosis==
* Netherton syndrome is diagnosed based on the symptoms and confirmed by [[genetic testing]] for changes in the''' SPINK5 gene'''.
Diagnosis of Netherton syndrome is based on clinical evaluation, family history, and genetic testing to identify mutations in the [[SPINK5]] gene. Skin biopsy and hair shaft analysis can also aid in diagnosis by revealing characteristic features of the disorder.
* Other types of testing, such as close examination of the hair and a skin [[biopsy]] to obtain a small skin sample for examining under the microscope can also be helpful for diagnosis.
== Treatment ==
==Management==
There is no known cure at the moment but there are several things that can be done to relieve the symptoms. Moisturising products are very helpful to minimize the scaling/cracking, and anti-infective treatments are useful when appropriate because the skin is very susceptible to infection. Extra protein in the diet during childhood is also beneficial, to replace that which is lost through the previously mentioned "leaky" skin.
There is no cure for Netherton syndrome, and management focuses on alleviating symptoms and preventing complications. Treatment strategies may include:
Steroid and retinoid products have been proven ineffective against Netherton syndrome, and may in fact make things worse for the affected individual.{{Citation needed|date=June 2010}}
* Topical and systemic therapies to manage skin inflammation and dryness
* Regular monitoring and treatment of infections
* Nutritional support to address growth and development issues
* Genetic counseling for affected families
Intravenous immunoglobulin has become established as the treatment of choice in Netherton's syndrome.<ref name="Renner"/> This therapy reduces infection; enables improvement and even resolution of the skin and hair abnormalities, and dramatically improves quality of life of the patients; although exactly how it achieves this is not known. Given this; it is possible that the reason Netherton's usually is not very severe at or shortly after birth is due to a protective effect of maternal antibodies; which cross the placenta but wane by four to six months.
==Prognosis==
The prognosis for individuals with Netherton syndrome varies depending on the severity of symptoms and the effectiveness of management strategies. With appropriate care, many individuals can lead relatively normal lives, although they may require ongoing medical support.
{{Congenital malformations and deformations of integument}}
[[Category:Autosomal recessive disorders]]
[[Category:Genodermatoses]]
[[Category:Rare diseases]]
[[Category:Syndromes affecting the skin]]
Revision as of 06:42, 16 February 2025
A rare genetic disorder affecting the skin, hair, and immune system
Netherton syndrome is a rare genetic disorder characterized by skin, hair, and immune system abnormalities. It is an autosomal recessive condition, meaning that an individual must inherit two copies of the defective gene, one from each parent, to be affected by the disorder.
Netherton syndrome is caused by mutations in the SPINK5 gene, which encodes the protein LEKTI (lympho-epithelial Kazal-type-related inhibitor). This protein plays a crucial role in skin barrier function and immune regulation. The disorder follows an autosomal recessive pattern of inheritance, as illustrated in the diagram.
Clinical Features
The clinical presentation of Netherton syndrome is highly variable but typically includes the following features:
Skin Abnormalities
Patients often present with ichthyosis linearis circumflexa, a condition characterized by red, scaly skin with a distinctive double-edged scale. Atopic dermatitis-like symptoms are also common, leading to chronic skin inflammation and irritation.
Hair Abnormalities
A hallmark of Netherton syndrome is trichorrhexis invaginata, also known as "bamboo hair," where the hair shaft is fragile and prone to breakage. This can lead to sparse and brittle hair.
Immune System Abnormalities
Individuals with Netherton syndrome may experience recurrent infections due to an impaired immune response. They are also at increased risk for atopy, including asthma, allergic rhinitis, and food allergies.
Diagnosis
Diagnosis of Netherton syndrome is based on clinical evaluation, family history, and genetic testing to identify mutations in the SPINK5 gene. Skin biopsy and hair shaft analysis can also aid in diagnosis by revealing characteristic features of the disorder.
Management
There is no cure for Netherton syndrome, and management focuses on alleviating symptoms and preventing complications. Treatment strategies may include:
Topical and systemic therapies to manage skin inflammation and dryness
Regular monitoring and treatment of infections
Nutritional support to address growth and development issues
Genetic counseling for affected families
Prognosis
The prognosis for individuals with Netherton syndrome varies depending on the severity of symptoms and the effectiveness of management strategies. With appropriate care, many individuals can lead relatively normal lives, although they may require ongoing medical support.
