Sialidosis, Type Ii

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 II, the more severe type of the disorder, is further divided into congenital, infantile, and juvenile forms. This type of sialidosis often begins during infancy or later during childhood and is characterized by cherry-red macules, mildly coarse facial features, skeletal malformations and mild cognitive impairment. Sialidosis type II is caused by mutations in the NEU1 gene. People with sialidosis type II have mutations that severely reduce or eliminate NEU1 enzyme activity. The condition is inherited in an autosomal recessive pattern.