Trichorrhexis invaginata is a distinctive hair shaft abnormality that may occur sporadically, either in normal hair or with other hair shaft abnormalities, or regularly as a marker for
Netherton's syndrome
Netherton syndrome is a severe, autosomal recessive form of ichthyosis associated with mutations in the ''SPINK5'' gene. It is named after Earl W. Netherton (1910–1985), an American dermatologist who discovered it in 1958.Netherton, E. W. A u ...
.
[Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. .][James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. .] The primary defect appears to be abnormal keratinization of the hair shaft in the keratogenous zone, allowing for intussusception of the fully keratinized and hard distal shaft into the incompletely keratinized and soft proximal portion of the shaft.
Genetics
"Bamboo hair" is a rare autosomal recessive
genodermatosis
Genodermatosis is a hereditary skin disease with three inherited modes including single gene inheritance, multiple gene inheritance and chromosome inheritance. There are many different types of genodermatosis, the prevalence of genodermatosis rang ...
characterized by congenital ichthyosiform erythroderma, trichorrhexis invaginata, and atopic
diathesis with failure to thrive. Chronic skin
inflammation
Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
results in scaling and
exfoliation, predisposing these patients to life-threatening infections,
sepsis
Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...
, and
dehydration
In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...
. The Netherton syndrome Mendelian Inheritance in Man is inherited as an autosomal recessive disorder due to mutations of both copies of the ''
SPINK5
Lympho-epithelial Kazal-type-related inhibitor (LEKTI) also known as serine protease inhibitor Kazal-type 5 (SPINK5) is a protein that in humans is encoded by the ''SPINK5'' gene.
Structure and function
LEKTI is a large multidomain serine prot ...
'' gene (localized to band 5q31-32), which encodes the serine protease inhibitor
LEKTI
Lympho-epithelial Kazal-type-related inhibitor (LEKTI) also known as serine protease inhibitor Kazal-type 5 (SPINK5) is a protein that in humans is encoded by the ''SPINK5'' gene.
Structure and function
LEKTI is a large multidomain serine prot ...
(lymphoepithelial Kazal-type-related inhibitor). LEKTI is expressed in epithelial and mucosal surfaces and in the
thymus
The thymus is a specialized primary lymphoid organ of the immune system. Within the thymus, thymus cell lymphocytes or ''T cells'' mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. ...
. Each ''SPINK5''
mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
leads to a different length of LEKTI protein, resulting in genotype/phenotype correlations in cutaneous severity, susceptibility to atopic
dermatitis
Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can v ...
,
growth retardation
Delayed milestone, also called developmental delays, is used to describe the condition where a child does not reach one of these stages at the expected age. However, in most cases, a wide variety of ages can be considered normal, and not a cause fo ...
,
skin infection
A skin infection is an infection of the skin in humans and other animals, that can also affect the associated soft tissues such as loose connective tissue and mucous membranes. They comprise a category of infections termed skin and skin structure ...
, increased stratum corneum protease activities, and elevated kallikrein levels in the stratum corneum.
Trichorrhexis invaginata, or bamboo hair, is a
hair shaft
Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals.
The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and fine ...
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
In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...
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
A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals.
Types
There is no designated classifi ...
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
Erythroderma is an inflammatory skin disease with redness and scaling that affects nearly the entire cutaneous surface.Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. p. 436. . This term applie ...
may cause profound metabolic abnormalities and hypernatremia, particularly in
neonates
An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...
.
Epidemiology
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. Girls are affected more often by trichorrhexis invaginata (bamboo hair) than boys, but is present in all races.
History
In 1937, Touraine and Solente first noted the association between hair-shaft defects (bamboo node) and ichthyosiform erythroderma. Còme first coined the term ichthyosis linearis circumflexa in 1949, although Rille had previously recorded the distinctive features of ichthyosis linearis circumflexa by 1922. 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
Ichthyosis linearis circumflexa is a distinctive skin condition of generalized hyperkeratosis and polycyclic and serpiginous erythematous plaques with a characteristic, migratory, double-edged scale at the margins, and is the typical cutaneous man ...
and Netherton syndrome, and an atopic diathesis was found to occur in approximately 75% of patients with Netherton syndrome.
[Mevorah B, Frenk E, Brooke EM. Ichthyosis linearis circumflexa comel. A clinico-statistical approach to its relationship with Netherton's syndrome. ''Dermatologica''. 1974.]
See also
*
Trichomegaly
Trichomegaly is a congenital condition in which the eyelashes are abnormally long, greater than 12mm in the central area and 8mm in the peripheral. The term was first used by H. Gray in 1944 in a publication in the Stanford Medical Bulletin, though ...
*
List of cutaneous conditions
Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against t ...
References
External links
{{Disorders of skin appendages
Conditions of the skin appendages