Weakening of the hair associated with pili torti also causes alopecia in approximately 80% of patients.The severity of hearing loss associated with Björnstad syndrome varies. Some individuals are unable to hear sounds at certain frequencies, while others are completely deaf. Their hearing loss is caused by tissue damage of the inner ear. Genetics
Björnstad syndrome is caused by a mutation in the BCS1L gene (position 2pq35) and is inherited in an autosomal recessive pattern. BCS1L is a protein that adds Rieske Fe/S to complex III during oxidative phosphorylation of cellular respiration. Mutations of BCS1L gene prevents the protein product from aiding in complex III formation, which reduces oxidative phosphorylation and increases the production of reactive oxygen species.Two missense mutations linked to Björnstad syndrome have been documented, but several other variants are suspected to be pathogenic. The clinical severity of different BCS1L mutations may be caused by the varying production of reactive oxygen species. The symptoms of Björnstad syndrome may be attributed to a particular sensitivity of inner ear and hair tissues to reactive oxygen species, but more research is needed. Mutations of the BCS1L gene may also result in GRACILE syndrome, which is an inherited lethal metabolic disease. Diagnosis
Roar Theodor Björnstad first noticed a correlation between pilli torti and hearing loss in 1965, and subsequently diagnosed eight patients with Björnstad syndrome. Out of these eight patients with pili torti, five experienced sensorineural deafness.
Several SDS patient groups are advocating for better therapies for SDS, and one organization is focused on driving the therapy development efforts. The challenge is whether the SDS community can come together to support the required research, and whether the organizations can successfully execute a strategy that coordinates the efforts for new therapy development. Epidemiology
It is thought to have an estimated incidence of 1 in 75,000 people. History
The disease was first described as a coherent clinical entity in May 1964 by Bodian, Sheldon, and Lightwood. It was subsequently described by Shwachman, Diamond, Oski, and Khaw in November of the same year. In 2001, linkage analysis in SDS families indicated that affected gene mapped to a large region of human chromosome seven. In 2002, this interval was refined to a region on the long arm of the chromosome next to the centromere.In 2003, a team of researchers led by Johanna Rommens at the Hospital of Sick Children (SickKids) in Toronto, Canada, discovered mutations in the SBDS gene (Shwachman–Bodian–Diamond syndrome) were associated with disease. Eponym
Shwachman–Diamond syndrome, less commonly known as Shwachman–Bodian–Diamond syndrome, is named for Harry Shwachman (1910 – September 12, 1986), an American physician, Martin Bodian (1912 – May 12, 1994), a British ophthalmologist who worked in New York City, and Louis Klein Diamond (May 11, 1902 – June 14, 1999), an American pediatrician. References
Further reading
Foerster (2014). "Ch 37. Inherited Aplastic Anemia Syndromes". In John P. Greer; Daniel A. Arber; Bertil Glader; Alan F. List; Robert T. Means Jr.; Frixos Paraskevas; George M. Rodgers; John Foerster (eds.).