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Blond hair is controlled by an allele that is recessive to most alleles responsible for darker hair, [1] but it is not a disappearing gene.. The "disappearing blonde gene" refers to a hoax that emerged in parts of the Western world in the early 2000s, claiming that a scientific study had estimated that blonds would become extinct within the next two centuries.
The shaft of normal hair (left) and hair in uncombable hair syndrome (right). The hair is normal in quantity and is usually silvery-blond or straw-colored. It is disorderly, stands out from the scalp, and cannot be combed flat, but it can be controlled by braiding methods. This is caused by mutations in one of three possible genes; PADI3, TGM ...
Mutations in PAX3 were first linked to this phenotype in 1992. [2] The comorbidity with Hirschsprung's disease, which would later constitute type 4, was first noticed in various studies in the 1970s. Indian paediatrician Krishnakumar Shah and his associates first outlined the syndrome as a possible variant of Waardenburg syndrome in 1981. [43]
Diagnosing ED usually involves a clinical examination focused on core symptoms, such as lack of sweating, specific dental and hair abnormalities, and characteristic facial features. Genetic testing can confirm the diagnosis, especially when there is a family history of ED or when prenatal screening is considered.
The vast majority of cases are thought to be due to spontaneous genetic mutations. [1] It can be associated with mutations affecting the cohesin complex. [4] [5]As of 2018, it was confirmed that 500 genetic mutations have been associated with the condition, occurring on seven different genes.
OCA1 is caused by mutations of the tyrosinase gene, and can occur in two variations. The first is OCA1a, and means that the organism cannot synthesize melanin whatsoever. [6] The hair is usually white (often translucent) and the skin is very pale. Vision usually ranges from 20/200 to 20/400. The second is OCA1b, which has several subtypes itself.
Birt–Hogg–Dubé syndrome (BHD), also Hornstein–Birt–Hogg–Dubé syndrome, Hornstein–Knickenberg syndrome, and fibrofolliculomas with trichodiscomas and acrochordons [1] is a human, adult onset, autosomal dominant genetic disorder caused by a mutation in the folliculin (FLCN) gene.
Hair diseases are illnesses that impact the persistence and regular growth of hair. Types of hair diseases include folliculitis , hirsutism , hypertrichosis , hypotrichosis ( alopecia ), Menkes kinky hair syndrome , monilethrix , and piedra .