Sjögren-Larsson syndrome

Sjögren-Larsson syndrome (SSL) is a neurocutaneous disease characterized by congenital ichthyosis, intellectual disability and spasticity. This syndrome is due to mutations in the ALDH3A2 gene, which encodes for the protein aldehyde dehydrogenase, an enzyme necessary for lipid metabolism.

The prevalence of SSL is estimated at 1 case per 250,000 population and is highest in Sweden.

The first symptoms may appear in the prenatal period and during infancy. Patients are usually born prematurely and present with mild hyperkeratosis that progresses to generalized ichthyosis, more developed on the flexural areas, nape of the neck, trunk and extremities. Unlike other forms of ichthyosis, pruritus or itching sensation is usually present.

Neurological signs appear during the first or second year of life. Psychomotor retardation occurs, usually due to cerebral palsy (spastic diplegia). Approximately half of the patients are unable to walk and seizures may occur. They often have motor speech difficulty or dysarthria resulting in speech delay. Intellectual disability varies from moderate to severe, although a few cases with normal intelligence have been reported. The neurological symptoms and intellectual deficit do not progress further after puberty.

Management involves the intervention of a multidisciplinary team of neurologists, dermatologists, ophthalmologists, orthopedic surgeons and physiotherapists. Available treatments focus on symptom relief, e.g., topical keratolytics may be used for ichthyosis and anticonvulsant drugs if required. Patients usually live to adulthood, but require lifelong care. Patients with early symptoms usually have more severe disease.