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About pili torti and nerve deafness

What is pili torti and nerve deafness?

Bjornstad syndrome is an extremely rare inherited disorder characterized by the presence of abnormally flattened, twisted hair shafts (pili torti) and, in most cases, deafness (sensorineural hearing loss). Hearing loss typically affects both ears (bilateral). Individuals with this disorder usually have dry, fragile, lusterless, and/or coarse scalp hair as well as areas of patchy hair loss (alopecia). Both autosomal dominant and recessive inheritance have been reported in the medical literature.

What are the symptoms for pili torti and nerve deafness?

Bjornstad syndrome is characterized by the presence of abnormally flat and twisted hair shafts defined as pili torti. BS patients usually present with dry, fragile, lusterless, and/or coarse scalp hair. When studied under an electron microscope, hair shafts from the scalp appear flattened and/or twisted (torti) at regular intervals. Body hair may exhibit the same characteristic twisting (pili torti) as scalp hair. In some patients, patchy areas of hair loss (alopecia) may be present on the scalp as well as on other areas of the body. However, the eyebrows and eyelashes are typically not affected. Light colored eyes and hair could be associated with BS and some individuals may also experience a lack of Sweating (anhidrosis). Most BS patients have deafness due to an impaired ability of the auditory nerves to transmit sensory input to the brain (sensorineural hearing loss).

Hair loss typically begins during the first two years of life and, although severity of symptoms and age of onset are variable, the hair abnormality may become milder with age. Hearing loss typically develops by 3 or 4 years of age and hearing impairment may lead to speech difficulties. Intellectual disability is not a typical feature of the syndrome but has been reported occasionally.

Hypogonadism, characterized by underdevelopment of the ovaries in females and of testes in males, has been described in some BS patients, but this is not typical.

What are the causes for pili torti and nerve deafness?

Bjornstad syndrome is caused by changes (mutations) in the BCS1L gene. This gene codes for a chaperone protein that is a member of the AAA family of ATPases. An ATPase is an enzyme that uses ATP (adenosine triphosphate), the main energy source in cells, to drive chemical reactions. This particular ATPase is involved in the assembly of complex III in the mitochondrial electron transport chain. The electron transport chain is responsible for generating the energy that cells require. Complex III also produces reactive oxygen species. When present in high numbers, these reactive compounds will cause damage to tissue. Even though this abnormal protein leads to a decrease in the activity of complex III, the complex will produce more reactive oxygen species.

The hair follicles and cells of the inner ear are particularly sensitive to these reactive oxygen species. This is thought to be the reason why hair changes and hearing loss are part of this syndrome.

Bjornstad syndrome is inherited in an autosomal recessive pattern. Recessive genetic disorders occur when an individual inherits a non-working gene from each parent. If an individual receives one working gene and one non-working gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk for two carrier parents to both pass the non-working gene and, therefore, have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier, like the parents, is 50% for each pregnancy. The chance for a child to receive working genes from both parents is 25%. The risk is the same for males and females.

What are the treatments for pili torti and nerve deafness?

There is no specific therapy for BS patients. Treatment is symptomatic and supportive and directed toward the specific symptoms present in each child. Care may require the skills of a team of specialists. Pediatricians, specialists who assess and treat hearing loss (audiologists) and physicians who specialize in diagnosing and treating disorders involving the skin (dermatologists) may coordinate their efforts to ensure the comprehensive, systematic treatment of affected children.

The treatment of patchy hair loss (alopecia) may include the use of wigs and/or other hair replacement therapies. Early detection and treatment of sensorineural deafness is essential to help avoid possible speech problems and assisted hearing devices may be prescribed to treat hearing loss.

Genetic counseling is recommended for affected individuals and their families.

What are the risk factors for pili torti and nerve deafness?

Bjornstad syndrome is an extremely rare disorder. In theory, it affects males and females in equal numbers. However, in observed cases, more females than males have been identified. Less than 50 cases are reported in the medical literature.

Is there a cure/medications for pili torti and nerve deafness?

Early intervention is important in ensuring that children with BS reach their full potential. Services that may be beneficial may include special remedial education, special services for children with congenital sensorineural deafness, and other medical, social, and/or vocational services.

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