Netherton Syndrome is a rare autosomal recessive genodermatosis characterized by congenital ichthyosiform erythroderma, an atopic diathesis, and a characteristic hair-shaft abnormality known as trichorrhexis invaginata. The condition begets the potential for severe complications for the affected individual, especially in the neonatal period. Chronic skin inflammation results in scaling and exfoliation, predisposing these patients to life-threatening infections, sepsis, and dehydration. Skin manifestations and associated symptoms may vary considerably among individuals with Netherton syndrome.
In 1937, Touraine and Solente  first noted the association between hair-shaft defects (bamboo node) and ichthyosiform erythroderma. Còmel  first coined the term ichthyosis linearis circumflexa in 1949, although more than two decades earlier Rille (Fruhwald  ) had previously recorded the distinctive features of ichthyosis linearis circumflexa. The condition is occasionally referred to as Còmel-Netherton syndrome.
In 1958, Netherton  described a young girl with generalized scaly dermatitis and fragile nodular hair-shaft deformities, which he termed trichorrhexis nodosa. Later, this was more appropriately renamed as trichorrhexis invaginata (bamboo hair) for a ball-and-socket–type hair-shaft deformity at the suggestion of Wilkinson et al. 
In 1974, Mevorah et al  established the clinical relationship between ichthyosis linearis circumflexa and Netherton syndrome, and an atopic diathesis was found to occur in approximately 75% of patients with Netherton syndrome.
The Netherton syndrome (Mendelian Inheritance in Man [MIM] #256500) is inherited as an autosomal recessive disorder due to mutations of both copies of the SPINK5 gene (localized to band 5q31-32),  which encodes the serine protease inhibitor LEKTI (lymphoepithelial Kazal-type-related inhibitor). LEKTI is expressed in epithelial and mucosal surfaces and in the thymus. It is crucial in regulating proteinases such as kallikreins, which degrade corneodesmosomes in the skin.  Each SPINK5 mutation leads to a different length of LEKTI protein, resulting in genotype/phenotype correlations in cutaneous severity, susceptibility to atopic dermatitis,  growth retardation, skin infection, increased stratum corneum protease activities, [10, 11] and elevated kallikrein levels in the stratum corneum. 
Trichorrhexis invaginata, or bamboo hair, is a hair shaft abnormality that occurs as a result of an intermittent keratinizing defect of the hair cortex. Incomplete conversion of the sulfhydryl –SH group onto S-S disulfide bonds in the protein of the cortical fibers leads to cortical softness and subsequent invagination of the fully keratinized distal hair shaft into the softer, abnormally keratinized proximal hair shaft. Intussusception of the distal hair shaft into the proximal hair shaft results in a distinctive ball-and-socket hair shaft deformity. The affected hairs are brittle and breakage is common, resulting in short hairs.
Migratory lesions of ichthyosis linearis circumflexa may be caused by a dermal influx of inflammatory cells that undergo phagocytosis and digestion by keratinocytes, resulting in disruption of keratinization.
Increased transepidermal water loss resulting from the disturbance of corneocyte barrier function in erythroderma may cause profound metabolic abnormalities and hypernatremia, [13, 14] particularly in neonates. 
The frequency of trichorrhexis invaginata (bamboo hair) is not known. Approximately 200 cases of trichorrhexis invaginata (bamboo hair) have been reported in the literature, but the true incidence is not known. The incidence of trichorrhexis invaginata (bamboo hair) may be as high as 1 case in 50,000 population. 
Netherton syndrome has been described in persons of all races.
Most cases of this condition have been reported in girls.
Children affected by Netherton syndrome present with erythroderma within 1-6 weeks of birth.
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