Salla disease is an extremely rare illness which is considered the mildest form of the free sialic acid accumulation disorders though its childhood form is considered an aggressive variant and people who suffer from it have mental retardation. It is an autosomic recessive disorder caused by a mutation of the chromosome 6. It mainly affects the nervous system  and it is caused by a lysosomal storage irregularity which comes from a deficit of a specific sialic acid carrier located on the lysosomal membrane Currently, there is no cure for this disease and the treatment is supportive, focusing on the control of symptoms.