Christianson syndrome

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Christianson syndrome
Specialty	Medical genetics
Causes	Mutation in SLC9A6 gene

Christianson syndrome is an X linked syndrome associated with intellectual disability, microcephaly, seizures, ataxia and absent speech.

Presentation[]

Onset of symptoms is normally within the first year of life with truncal ataxia and seizures. The head is small (microcephaly). Common facial abnormalities include^{[citation needed]}

• Long narrow face
• Prominent nose
• Prominent jaw
• Large ears
• Open mouth
• Thick eyebrows

Other common features include^{[citation needed]}

• Uncontrolled drooling
• Abnormal eye movements

The associated intellectual disablity is usually in the profound range.

Those affected often have a happy demeanor with frequent smiling and spontaneous laughter.

Genetics[]

This condition is caused by mutations in the SLC9A6 gene. This gene is located on the long arm of the X chromosome (Xq26.3).The gene encodes a sodium/hydrogen exchanger located in the endosomes. Mutations in this gene cause a rise in the pH of the endosomes.^{[citation needed]}

How this causes the clinical features is not known presently. The inheritance of this condition is X-linked dominant.

Diagnosis[]

The diagnosis may be suspected on clinical grounds.It is made by sequencing the SLC9A6 gene.^{[citation needed]}

Differential diagnosis[]

• Angelman syndrome
• Spinocerebellar ataxia type 29

Management[]

There is presently no curative treatment. Management is supportive.^{[citation needed]}

Epidemiology[]

The prevalence is not known but this is considered to be a rare disease.

History[]

This condition was first described in 1999.^[1] The causative mutation was discovered in 2008.^[2]

References[]