Christianson syndrome is an X-linked syndrome associated with intellectual disability, microcephaly, seizures, ataxia, and absent speech. Many individuals with this condition have a happy demeanor with frequent smiling and unprovoked laughter, similar to those with Angelman syndrome. Christianson syndrome is caused by mutations in the SLC9A6gene, which is located within the q24-q27 interval of the X chromosome. There appears to be a range of phenotypes in carrier females, from intellectual disability to absence of symptoms.
Last updated: 1/26/2015
How many people have been diagnosed with Christianson syndrome?
In 1999, Christianson et al. described a 5-generation South African family with X-linked mental retardation, comprising 16 affected males and 10 carrier females. In 2008, Gilfillan et al. reported 3 additional families with the disorder: a Norwegian family with 3 affected males; a Swedish family with 1 affected son; and a family from the United Kingdom with 3 affected boys. In 2010, Schroer et al. reported a large family with 6 additional confirmed cases.
In 2014, 12 additional families with boys affected by Christianson syndrome were identified in a large study. At present medical researchers believe Christianson syndrome may be one of the most common causes of X-linked brain development disorders. Medical researchers estimate the condition may affect between 1 in 16,000-100,000 people worldwide.
Last updated: 12/21/2015
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Mental Retardation, X-Linked, Syndromic, Christianson Type. Online Mendelian Inheritance in Man (OMIM). February 24, 2015; http://omim.org/entry/300243. Accessed 12/21/2015.
Gilfillan GD, Selmer KK, Roxrud I, Smith R, Kyllerman M, Eiklid K, Kroken M, Mattingsdal M, Egeland T, Stenmark H, Sjøholm H, Server A, Samuelsson L, Christianson A, Tarpey P, Whibley A, Stratton MR, Futreal PA, Teague J, Edkins S, Gecz J, Turner G, Raymond FL, Schwartz C, Stevenson RE, Undlien DE, Strømme P. Am J Hum Genet. 2008; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2427207/?tool=pubmed. Accessed 1/6/2010.
Pescosolido MF, Stein DM, Schmidt M, El Achkar CM, Sabbagh M, Rogg JM, Tantravahi U, McLean RL,Liu JS, Poduri A, & Morrow EM. Genetic and phenotypic diversity of NHE6 mutations in Christianson syndrome. Ann Neurol. Oct 2014; 76(4):581-93. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4304796/. Accessed 12/21/2015.