Sjogren-Larsson Syndrome

Gene : ALDH3A2

What is Sjogren-Larsson Syndrome?

Sjogren-Larsson Syndrome (SLS) is an inherited disorder caused by a defective enzyme called fatty aldehyde dehydrogenase. The most common symptoms of SLS are ichthyosis, which is thickened fish-like skin, muscle tightness in the legs, and intellectual disability. Ichthyosis often becomes progressively worse and is accompanied by itchiness of the skin). Infants with SLS are typically born prematurely. About half of individuals with SLS are never able to walk due to the abnormal muscle stiffness in their legs, and about 40% will have seizures. Intellectual disability varies from mild to severe, although rare individuals with normal intellect have been reported. The normal eye functions are also commonly impaired, but do not typically lead to complete vision loss. People with SLS usually survive until adulthood but require life-long care. No progression of the neurologic findings or intellectual disability occurs after puberty. Those with early symptoms tend to be more severely affected. Sjogren-Larsson Syndrome is caused by pathogenic variants in ALDH3A2 gene.

How is Sjogren-Larsson Syndrome inherited?

SLS is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant in the gene for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

What does it mean to be a carrier?

There are generally no signs or symptoms associated with being a carrier for SLS. However, the risk to have a child affected with SLS is increased. Testing of reproductive partners is recommended for carriers of SLS.

How common is Sjogren-Larsson Syndrome?

Sjogren-Larsson Syndrome occurs in 1 in 250,000 newborns in the general population, but the syndrome is more common in Sweden.

Family References and Resources
Clinician References
What is Analyzed?
  • Full gene sequencing
Affected Systems




Carrier Rates
Detection Rate
Carrier Frequency
General Population > 99% 1 in 223
Northern European Caucasian > 99% 1 in 223

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