The first sign of Sjögren-Larsson syndrome is often preterm birth. Apparent at birth, the ichthyosis associated with SLS often starts as thickened skin that is yellow-brown in color (hyperkeratosis). This thickened skin eventually progresses to full scaling, especially at the neck, lower abdomen, and underarms, groin, and back of knees (flexures). Unique to SLS is the itchy characteristic of the skin (pruritis).
The second feature of SLS is the stiffening of the muscles (spastic paresis). This affects the legs more often than the arms. Some individuals with SLS can walk without support, but as the stiffening worsens over time many individuals opt to use a wheelchair.
The other main clinical feature of SLS is intellectual disability. Most patients reach an average developmental age of 5-6 years of age.
Other features that could be seen include seizures, speech difficulty, short stature, spinal abnormalities (kyphoscoliosis), smaller head and brain (microcephaly), numbness in the hands and feet (peripheral neuropathy), widely spaced teeth, under-formed enamel of the teeth, widely spaced eyes, and uncontrolled movements of the eyes (nystagmus).
The symptoms of the condition can vary, even within families. However, Scaling skin (ichthyosis), intellectual disability, and Muscle stiffness (spastic paresis) are always seen. The average lifespan for affected males and females is 15 years and 26 years, respectively.