Sialidosis is a severe inherited disorder that affects many organs and tissues, including the nervous system. This disorder is divided into two types, which are distinguished by the age at which symptoms appear and the severity of features. Sialidosis type I
is the less severe form of this condition. People with this condition typically develop signs and symptoms of sialidosis in their teens or twenties. Characteristic features may include sudden involuntary muscle contractions (myoclonus), distinctive red spots (cherry-red macules) in the eyes, and sometimes additional neurological findings. Sialidosis type I is caused by mutations in the NEU1 gene. Individuals with sialidosis type I have mutations that result in some functional NEU1 enzyme. The condition is inherited in an autosomal recessive pattern. It does not affect intelligence or life expectancy. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.