Christianson syndrome

Genetics

• This is caused by mutations in the SCL9A6 gene
• The gene encodes endosomal Na+/H+ exchanger (NHE-6) protein
• It is a cause of X-linked mental retardation (XLMR)
• There are tau deposits pathologically

Dysmorphic features

Developmental features

Epileptic features

Other features

Symptomatic female features

Differential diagnosis

Magnetic resonance imaging (MRI) brain: features

Electroencephalogram (EEG): features

References

1. Christianson AL, Stevenson RE, van der Meyden CH, et al. X linked severe mental retardation, craniofacial dysmorphology, epilepsy, ophthalmoplegia, and cerebellar atrophy in a large South African kindred is localised to Xq24-q27. J Med Genet 1999; 36:759-766.
2. Masurel-Paulet A, Piton A, Chancenotte S, et al. A new family with an SLC9A6 mutation expanding the phenotypic spectrum of Christianson syndrome. Am J Med Genet A 2016; 170:2103-2110.
3. Zanni G, Barresi S, Cohen R, et al. A novel mutation in the endosomal Na+/H+ exchanger NHE6 (SLC9A6) causes Christianson syndrome with electrical status epilepticus during slow-wave sleep (ESES). Epilepsy Res 2014; 108: 811-815. 
4. Garbern JY, Neumann M, Trojanowski JQ, et al. A mutation affecting the sodium/proton exchanger, SLC9A6, causes mental retardation with tau deposition. Brain 2010; 133:1391-1402. 
5. Padmanabha H, Saini AG, Sahu JK, Singhi P. Syndrome of X linked intellectual disability, epilepsy, progressive brain atrophy and large head associated with SLC9A6 mutation. BMJ Case Rep 2017; pii: bcr-2017-222050. 
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