There are four different types of sialidosis. The types are distinguished by the age at which symptoms begin and the types of symptoms present. The effects of the disease may range from mild to severe.
Symptoms
There are two main types of sialidosis called type I and type II. Within type II there are three subtypes. The typical symptoms of the types are:
- Type I
- may begin any time between ages 8 and 25 years
- cherry red spots on the macula (part of the retina)
- jerking muscle contractions (myoclonus)
- lack of coordination (ataxia)
- Type II congenital form
- symptoms begin before birth and are present in the newborn
- may have hydrops fetalis (accumulation of fluid in the body) before birth
- may be stillborn or only live a short time after birth
- enlarged liver and spleen (hepatosplenomegaly)
- mental retardation
- coarse facial features
- dysostosis multiplex (defective bone formation)
- Type II infantile form
- begins within the first year of life
- coarse facial features
- enlarged liver (hepatomegaly)
- mental retardation
- dysostosis multiplex (defective bone formation)
- some individuals may have cherry-red spots on the macula (part of the retina)
- kidney problems
- Type II juvenile form
- may begin any time between ages 2 and 20 years
- mildly coarse facial features
- less severe bone changes than other forms
- mental retardation
- jerking muscle contractions (myoclonus)
- cherry red spots on the macula (part of the retina)
- angiokeratomas (dilated blood vessels under wart-like growths)
Diagnosis
The symptoms the child or young adult is experiencing will point to the diagnosis of sialidosis. A urine test would show the presence of a glycoprotein storage disease. This would be followed by a blood test or skin sample (biopsy), which would show deficiency of alpha-neuraminidase and confirm the specific diagnosis of sialidosis. X-rays can show the presence of dysostosis multiplex.
Treatment
There is at present no cure for sialidosis, so treatment focuses on the symptoms the individual is experiencing. Medications may be helpful in reducing myoclonus and managing seizures if they develop. An eye doctor (ophthalmologist), a neurologist, and a geneticist, among other specialists, will be involved in providing care.
Sources:
- Roth, Karl. "Sialidosis (Mucolipidosis I)." eMedicine 07 Jul 2006 <http://www.emedicine.com/ped/topic2093.htm>.
- "Sialidosis Fact Sheet." ISMRD: The Diseases. 2005. ISMRD. 9 Mar 2007 <http://www.mannosidosis.org/sialidosisFactSheet.htm>.
