Sjögren–Larsson syndrome

Not to be confused with Sjögren's syndrome, an autoimmune disorder which can cause many problems including dry skin.

Sjögren–Larsson syndrome is a rare autosomal recessive form of ichthyosis with neurological symptoms.^{[1]: 485 [2]: 564 [3]} It can be identified by a triad of medical disorders. The first is ichthyosis, which is a buildup of skin to form a scale-like covering that causes dry skin and other problems. The second identifier is paraplegia which is characterized by leg spasms. The final identifier is intellectual delay.

Sjögren–Larsson syndrome
Other names	SLS
Two brothers (21 and 25 years old) with generalized dryness of skin with fine scales mainly around the umbilicus and in the flexural folds, one of Sjögren–Larsson syndrome's characteristics
Specialty	Medical genetics

SLS is caused by a mutation in the fatty aldehyde dehydrogenase gene found on chromosome 17.^[4] In order for a child to receive SLS both parents must be carriers of the SLS gene. If they are carriers their child has a ⁠1/4⁠ chance of getting the disease. In 1957 Sjögren and Larsson proposed that the Swedes with the disease all descended from a common ancestor 600 years ago. Today only 30–40 persons in Sweden have this disease.^[5]

Signs and symptoms

T2-weighted MRI images of a 25-year-old male with Sjögren–Larsson syndrome revealing dysmyelination in the deep periventricular white matter and reduced brain volume in the frontal lobe

• Dry and scaly skin similar to all other ichtyosiforms (types of ichthyosis).
• Neurological problems – this can often cause mild paralysis in the legs
• Mild to moderate intellectual disability.
• Often associated ocular features, which include pigmentary changes in the retina.

The usual presentation of crystalline maculopathy is from the age of 1–2 years onwards.^{[citation needed]}

Causes

It is associated with a deficiency of the enzyme fatty aldehyde dehydrogenase (ALDH3A2) which is encoded on the short arm of chromosome 17 (17p11.2). At least 11 distinct mutations have been identified.^[6]

Without a functioning fatty aldehyde dehydrogenase enzyme, the body is unable to break down medium- and long-chain fatty aldehydes which then build up in the membranes of the skin and brain.^[4]

This condition is inherited in an autosomal recessive pattern.^[7]

Diagnosis

Diagnosis is made with a blood test which sees if the activity of the fatty aldehyde dehydrogenase enzyme is normal.^[4] Gene sequencing can also be used, which can additionally be used by would-be parents to see if they are carriers.^[4]

Treatment

The ichthyosis is usually treated with topical ointment.^[4] Anti-convulsants are used to treat seizures^[4] and the spasms may be improved with surgery.^[4]

Eponym

It was characterized by Torsten Sjögren and Tage Konrad Leopold Larsson (1905–1998), a Swedish medical statistician.^[8][9] It should not be confused with Sjögren's syndrome, which is a distinct condition named after a different person, Henrik Sjögren.^{[citation needed]}

See also

• Shabbir syndrome
• List of cutaneous conditions