What Is Björnstad Syndrome?

  • Geraint Duffy Master of Science - MSc, Medical Biotechnology and Business Management, University of Warwick
  • Bea Brownlee BSc (Hons), Medical Microbiology, University of Leeds

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Björnstad syndrome is a very rare genetic condition that mainly affects the hair and hearing. This usually causes abnormally flat and twisted hair (pili torti) and hearing loss.1,3,8 Björnstad syndrome was first identified in 1965, and less than 50 cases have been noted worldwide to this day.1,3,7 The severity of the symptoms can be different in each person with Björnstad syndrome.

It is important to understand and promptly receive treatment for Björnstad syndrome for many reasons, including to prevent further complications and improve quality of life by receiving appropriate help to manage the condition.

Causes and risk factors

The main cause and risk factor for Björnstad syndrome is genetics. The risk of having Björnstad syndrome is higher if both of your parents have a defective BCS1L gene.2,4,5 The normal BCS1L gene is important for the normal functioning of the mitochondria in our cells.5 Mitochondria are crucial in producing energy to ensure that our cells are working properly. 

When the mitochondria are not functioning properly, cells are vulnerable to oxidative stress caused by reactive oxygen species. It has been suggested that the hair follicles and tissues in the inner ears are sensitive and especially susceptible to damage from this.

It is important to note that having the risk factor does not mean you will 100% get the condition. If you have any questions or concerns, speak to your healthcare provider. 

Symptoms and complications 

Common signs and symptoms

The severity of symptoms can be different in each person with Björnstad syndrome. The abnormal signs are usually noticed in early childhood before the age of 2. There are three common signs and symptoms present in 80-99% of people with Björnstad syndrome, which are:1,2,3,7,8

  • Abnormally flat and twisted hair (pili torti) – hair may also be dry and fragile due to loss of keratin. Keratin is important to maintain the strength of our hair
  • Patchy hair loss (alopecia) – especially on the back and side of the head (eyelashes, eyebrows, armpit and pubic hair are usually not affected). Hair loss can be progressive
  • Hearing loss (sensorineural deafness) – This is caused by damage to the hair cells in the inner ear, which convert sound waves into electrical messages for our brain to understand. Hearing loss can be present at birth or may develop during early childhood, and it can vary from mild to severe. Some people may not hear a certain pitch of sounds or can have a complete loss of hearing

Studies have found that in most people with Björnstad syndrome, the severity of hair abnormalities and hearing loss go hand in hand.1,3,6

Although not common and not fully known why, the following may also develop:1,3

  • Delay in child growth
  • Hypogonadism (underdeveloped reproductive organs)
  • Delay in the development of secondary sexual features during puberty, for example, breasts and hair growth 
  • Intellectual disability
  • Skin changes – pigmentation or thinning
  • Muscle weakness
  • Loss of coordination
  • Eye abnormalities – crossed eyes or involuntary eye movements
  • Seizures

Possible complications 

There are several complications of Björnstad syndrome if left untreated; these are not limited and may include:1,2,3,7,10

  • Permanent hearing loss 
  • Delay in the development of reproductive organs 
  • Liver failure
  • Neonatal renal tubulopathy (a type of kidney disease in newborns)
  • Encephalopathy
  • GRACILE syndrome
  • Delay in child growth 
  • Aminoaciduria – where amino acids are present in the urine due to kidney problems 
  • Cholestasis – where a liquid called bile, which helps digest food, is not circulating in the liver properly, causing liver issues
  • Iron overload 
  • Lactic acidosis – where lactic acid accumulates in the body, which can cause further complications with metabolism, blood and tissues 
  • Early death – due to severe complications 

Diagnostic procedures

Early diagnosis is important for earlier treatment and addressing other potential complications. Björnstad syndrome is diagnosed by healthcare specialists and can include the following:1 

Clinical evaluation

Your healthcare professional will check your symptoms and any medical conditions you and your family may have. They will also perform a thorough physical examination. 

Electron microscope studies

The diagnosis of Björnstad syndrome can be confirmed by examination of twisted hair shafts under an electron microscope. The electron microscope allows us to see the hair in greater magnification and detail. 

Specialised hearing tests

Since most people with Björnstad syndrome have some degree of hearing loss, individuals will be recommended for thorough specialised hearing tests to evaluate or determine the degree of sensorineural deafness.

Genetic testing

Genetic testing may be recommended to confirm the genetic cause (BCS1L gene defect)

Other tests 

These depend on individual symptoms and presentations to check if the organs are working normally:

  • Neurological tests
  • Blood tests
  • Dermatological tests

Treatment options

There is currently no cure available for Björnstad syndrome. However, there are various treatments available to help manage the symptoms and effectively reduce the risk of getting worse. Treatment options are recommended by healthcare professionals after a thorough health check and discussion with the individual to select what is most appropriate for them. Paediatricians, audiologists, and dermatologists could be among the first to respond. Some of the treatments may include:1,2,3

Regular monitoring 

Healthcare professionals may recommend regular check-ups to check how you are managing the symptoms and address any further treatment plans.

Assisted hearing devices

Sensorineural deafness should be detected and treated early to avoid potential speech issues. Administration of hearing aids may treat hearing loss. 

Minimisation of hair trauma

Hair is fragile. Therefore, it is recommended to minimise vigorous shampooing, combing, hair styling treatments or perms. Wigs and other hair replacements may be offered. 

Supportive care 

To help manage the symptoms and adjust to life. These are not limited to and may include the following:

  • Physiotherapy 
  • Educational support
  • Speech and language therapy
  • Psychological therapy 
  • Occupational therapy
  • Genetic counselling

Emerging treatment 

There are various clinical trials, gene therapies and ongoing research that you may be eligible for. These can be discussed with your healthcare provider.


There are currently no ways to prevent Björnstad syndrome. But the following steps may be considered if you have or are at a higher risk of having Björnstad syndrome:

Early detection 

Being aware of Björnstad syndrome can help with planning the best treatments for you and effectively minimise the risk of symptoms worsening.

Genetic counselling and family planning 

If you are considering having children, a genetic counsellor can provide you with information about the risks and further options. 

Prenatal testing

Prenatal testing (tests performed during pregnancy) may be available for families at higher risk of passing on the mutated BCS1L gene to their babies.


Björnstad syndrome is a rare genetic condition that is caused by an abnormal BCS1L gene that is normally required for the healthy functioning of the mitochondria. Defects in this BCS1L gene can cause various symptoms. The hair follicles on the scalp and inner hair cells in our inner ear are particularly vulnerable to these changes. Therefore, the majority of individuals with Björnstad syndrome experience abnormal hair shafts (known as pili torti) and hearing loss, which can be permanent. 

Although there is no current cure available, there are various treatment options to help manage the symptoms and prevent them from deteriorating. Research is still ongoing to better understand this condition and to enable the development of effective treatments. If you or anyone you know is concerned about Björnstad syndrome, please speak to your doctor for more thorough and personalised support.  


What is Björnstad syndrome?

Björnstad syndrome is a rare genetic condition caused by an abnormal BCS1L gene that is normally required for healthy and effective functioning of the mitochondria. Most people with Björnstad syndrome commonly have issues with hair (pili torti) and hearing loss.  

What causes Björnstad syndrome?

Björnstad syndrome is caused by a genetic mutation of the BCS1L gene. It is usually inherited in an autosomal recessive manner, which means that both parents must carry and pass on the mutated BCS1L to their child.  

What are the symptoms of Björnstad syndrome?

Over 80% of people with Björnstad syndrome have reported permanent hearing loss and abnormal hair shaft (pili torti) with hair loss.   

Why is the hearing affected? 

We have hair cells in our inner ear. This is important for converting sound vibrations from our environment into electrical signals to allow our brain to understand.

What age does the symptom first appear?

Most often, the symptoms are noticed by the age of 2.  

What is pili torti?

Pili torti is a hair abnormality where the hair is flattened with a twisted, weak, and fragile hair shaft. 

How is Björnstad syndrome diagnosed?

Björnstad syndrome is diagnosed by a combination of clinical evaluations, electron microscopy, genetic tests, and hearing tests to confirm. 

Is there a cure for Björnstad syndrome?

There is no specific cure for Björnstad syndrome at the moment. But there are treatments available such as hearing aids and hair care support to manage the symptoms. 

Who is more likely to get Björnstad syndrome?

Björnstad syndrome is rare, with less than 50 cases found so far worldwide. Individuals with a family history of the condition are more likely to be affected. All genders are prone to Björnstad syndrome, regardless of ethnicity.  

What is the outlook for individuals with Björnstad syndrome?

The prognosis for Björnstad syndrome is reported to be better with earlier diagnosis and appropriate treatment of the symptoms. 


  • Aggarwal D, Sardana K, Kumar P, Dewan V, Anand VK. Bjornstad syndrome. The Indian Journal of Pediatrics. 2004 Aug;71(8):759–61.
  • Hoffmann A, Waśkiel-Burnat A, Żółkiewicz J, Blicharz L, Rakowska A, Goldust M, et al. Pili Torti: A Feature of Numerous Congenital and Acquired Conditions. Journal of Clinical Medicine [Internet]. 2021 Aug 30 [cited 2023 Aug 17];10(17):3901. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8432236/
  • Richards KA, Mancini AJ. Three members of a family with pili torti and sensorineural hearing loss: The Bjornstad syndrome. Journal of the American Academy of Dermatology. 2002 Feb;46(2):301–3.
  • Falco M, Franzè A, Iossa S, De Falco L, Gambale A, Marciano E, et al. Novel compound heterozygous mutations in BCS1L gene causing Bjornstad syndrome in two siblings. American Journal of Medical Genetics Part A. 2017 Mar 21;173(5):1348–52.
  • Lubianca Neto JF, Lu L, Eavey RD, Flores MAM, Caldera RM, Sangwatanaroj S, et al. The Bjornstad Syndrome (Sensorineural Hearing Loss and Pili Torti) Disease Gene Maps to Chromosome 2q34-36. The American Journal of Human Genetics [Internet]. 1998 May 1 [cited 2023 Aug 19];62(5):1107–12. Available from: https://www.sciencedirect.com/science/article/pii/S0002929707615328
  • Voigtländer V. Pili Torti with Deafness (Bjørnstad Syndrome). Dermatology. 1979;159(1):50–4.
  • Della Marina A, Leiendecker B, Roesch S, Wortmann SB. Ketogenic diet for treating alopecia in BCS1l-related mitochondrial disease (Bjornstad syndrome). JIMD Reports. 2020 Feb 17;
  • Vakifahmetoglu-Norberg H, Ouchida AT, Norberg E. The role of mitochondria in metabolism and cell death. Biochemical and Biophysical Research Communications [Internet]. 2017 Jan [cited 2023 Aug 22];482(3):426–31. Available from: https://www.sciencedirect.com/science/article/pii/S0006291X16319519 

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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Nisha Gurung

Nisha is a current Medical Student at St George’s University of London. She completed her MSci degree in Cell Biology at UCL. She fulfils multiple responsibilities including as a research assistant, peer mentor for In2MedSchool and advocates for careers.

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