User:Joimes/sandbox

{{Infobox medical condition |name         = Hypotrichosis |synonym      = |image        = |image_size   = |alt          = |caption      = |pronounce    = |specialty    = |symptoms     = |complications = |onset        = |duration     = |types        = |causes       = Genetic |risks        = |diagnosis    = |differential = |prevention   = |treatment    = |medication   = |prognosis    = |frequency    = |death {TOC left}}

Hypotrichosis simplex
Is a form of hereditary hypotrichosis without any other abnormalities seen in other example of hypotrichosis. Hair is present but interspersed and thin and can be limited to the scalp (called scalp limited) or in the generalized form that affect all hair on the body.

Autosomal recessive hypotrichosis
Short, sparse and fragile hairs are on the scalp and other parts of the body. In rare cases, the disease is associated with the wooly (tightly curled) hair.

Aplasia cutis congenita
Arises from an absence of skin from birth resulting in no hair growth in this area.

Triangular alopecia
Is a genetic disease that usually affects the frontotemporal region as a lancet, oval or triangular region of hair loss on the scalp without any scarring. In rare cases, it may affect the temporoparietal or occipital regions of the scalp.

Signs and Symptoms
There are many examples of diseases that involve hypotrichosis with many symptoms. Most diseases involve sparse hair on the scalp.



Hypotrichosis simplex
Hypotrichosis simplex can be inherited as an autosomal dominant or autosomal recessive trait. Autosomal dominant hereditary hypotrichosis simplex is caused by hair follicle miniaturization in which terminal hair is replaced by vellus hair. In scalp limited form a hypotrichosis simplex, it is caused by a heterozygous nonsense mutation in the CDSN gene. This gene codes for corneodesmosin, which is expressed in the epithelium in structures called desmosomes during cornification. This area of expression suggests corneodesmosin is necessary for hair follicle integrity. Cases of generalized hypotrichosis are rarely reported.

Autosomal recessive hypotrichosis
Autosomal recessive hypotrichosis can be caused by mutations in LIPH, LPAR6, and DSG4 genes.


 * The DSG4 gene encodes for the desmolglein 4 protein. This protein is expressed in desmosomes in regions of the hair follicle and in cutaneous regions . This protein is involved in the proliferation and differentiation of cells in the skin and the hair follicle. Mutations in this gene cause structurally abnormal hair follicles or skin because DSG4 associated with the skin.
 * The LIPH gene encodes for lipase H which synthesises Lysophosphatidic acid (LPA). LPA regulates proliferation and differentiation, thus mutations in the LIPH gene cause abnormal hair follicles resulting in fragile hair due to the lack of functional lipase H. Additionally, it can also cause skin problems.

Aplasia cutis congenita
Aplasia cutis congenita is an autosomal dominant disease that includes hypotrichosis, caused by the absence congenital absence of skin mostly observed on the scalp but can occur on other parts of the body. Aplasia cutis congenita is caused by a mutation in the BMS1 gene. This is most commonly on the scalp but can be present on the limbs and other parts of the body.

Triangular alopecia
These regions will completely lack hair or have vellus hair present. The exact cause of Congenital triangular alopecia is unclear however, some believe it is caused by a loss of heterozygosity as phakomatosis pigmentovascularis is associated with the disease. Alternatively, congenital triangular alopecia may be caused by mosaicism in which the disease arises from a postzygotic loss of the wild-type allele from a heterozygous state, resulting in a paradominant inheritance pattern.

Treatment
There are no current treatments for hypotrichosis as it is mostly caused by genetics. However, it can be managed by hiding hair loss with wigs, toupees, or accessories such as hats and beanies. Hypotrichosis of eyebrows, seen in autosomal recessive hypotrichosis can be managed through makeup, micropigmentation or embroidery. Furthermore, hair transplantation is a surgical option for individuals affected by hypertrichosis in which donor sites such as thicker parts of the scalp, hair from other parts of the body and transplanting it into areas that are needed.

Aplasia cutis congenita can be treated by keeping affected area cleaned to avoid infection. Smaller areas will usually heal over.

In animals
Hypotrichosis in animals implies the presence of less than normal amounts of hair as opposed to alopecia which is the complete absence of hair in animals. It can be congenital or tardive. It may be associated with defects of ectodermal origin such as anodontia, and in other ectodermal structures.

Calves with hypotrichosis are more prone to infection and the environment as they are born with no hair that grows into a woolly (short and curly) coat as it matures. Hypotrichosis within cattle is associated with, hypotrichosis with anodontia in German Holstein cattle, poorly developed horns in Ayrshire calves , and inherited epidermal dysplasia in cattle of Holstein-Friesian ancestry.