Free sialic acid storage disease
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
Age of Onset
Autosomal dominant ?A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease
Autosomal recessive ?Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype
X-linked dominant ?X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.
X-linked recessive ?Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder
Mitochondrial or multigenic ?Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.
Multigenic or multifactor ?Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.
Other Names (AKA)
Sialic acid storage disease; N-Acetylneuraminic acid storage disease (former); NANA storage disease (former);
Congenital and Genetic Diseases
Free sialic acid storage diseases are
General symptoms of free sialic acid storage diseases include
Infants with the most severe form of free sialic acid storage disease have symptoms that usually appear before or at the time of birth. The signs and symptoms of infantile free sialic acid storage disease include:
• Abnormal fluid buildup before birth (hydrops
• Fluid in the stomach (ascites)
• Low muscle tone (
• Enlarged liver and spleen (
• Coarse facial features
• Failure to gain weight
• Bone abnormalities
• Enlarged heart (cardiomegaly)
• Kidney damage
• Low muscle tone (hypotonia)
• Developmental delay and intellectual impairment
• Abnormal movements
-Uncontrolled or uncoordinated movements (
-Stiff or rigid muscles (
-Involuntary, writhing movement (athetosis)
• Some coarsening of facial features
• Loss of motor and speech skills
Very few people have been diagnosed with the intermediate severe form of free sialic acid storage disease. The severity of the signs and symptoms of this condition tend to fall between the other two forms.
This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.
|Medical Terms||Other Names||
|80%-99% of people have these symptoms|
|Abnormal foot morphology||
Abnormal feet structure
Abnormality of the feet
Abnormality of the foot
[ more ]
|Abnormal pyramidal sign||0007256|
|Aplasia/Hypoplasia of the abdominal wall musculature||
Absent/small abdominal wall muscles
Absent/underdeveloped abdominal wall muscles
[ more ]
[ more ]
|Global developmental delay||0001263|
Mental retardation, nonspecific
[ more ]
Low or weak muscle tone
Involuntary, rapid, rhythmic eye movements
Involuntary muscle stiffness, contraction, or spasm
|30%-79% of people have these symptoms|
|Abnormal facial shape||
Unusual facial appearance
|Abnormality of skin pigmentation||
Abnormal skin color
Abnormal skin pigmentation
Abnormality of pigmentation
Pigmentary skin changes
[ more ]
|Abnormality of the upper limb||0002817|
Accumulation of fluid in the abdomen
Involuntary writhing movements in fingers, hands, toes, and feet
Difficulty articulating speech
|Failure to thrive in infancy||
Faltering weight in infancy
Weight faltering in infancy
[ more ]
Light eye color
|Recurrent respiratory infections||
Frequent respiratory infections
Multiple respiratory infections
respiratory infections, recurrent
Susceptibility to respiratory infections
[ more ]
|Reduced bone mineral density||
Low solidness and mass of the bones
Open skin sore
|5%-29% of people have these symptoms|
High urine protein levels
Protein in urine
[ more ]
Increased spleen size
Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
Hide and Seek Foundation for Lysosomal Storage Disease Research
6475 East Pacific Coast Highway
Long Beach, CA 90803
Toll-free: (844) 762-7672
These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.
- MedlinePlus Genetics contains information on Free sialic acid storage disease. This website is maintained by the National Library of Medicine.
- The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
- The Salla Treatment and Research Foundation offers a description of Salla disease and features stories of children living with this rare condition.
- GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
- The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
- Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
- PubMed is a searchable database of medical literature and lists journal articles that discuss Free sialic acid storage disease. Click on the link to view a sample search on this topic.
- Adams D, Gahl WA. Free Sialic Acid Storage Disorders. GeneReviews. Updated June 6, 2013; https://www.ncbi.nlm.nih.gov/books/NBK1470/.
- Free Sialic Acid Storage Disorders. National Organization for Rare Disorders (NORD). Updated 2016; https://rarediseases.org/rare-diseases/lysosomal-free-sialic-acid-storage-disorders/.
- Sialic acid storage disease. Genetics Home Reference. February 2008; https://ghr.nlm.nih.gov/condition/sialic-acid-storage-disease.
- Barmherzig R, Bullivant G, Cordeiro D, Sinasac DS, Blaser S, Mercimek-Mahmutoglu S. A new patient with intermediate severe Salla disease with hypomyelination: A literature review for Salla disease.. Pediatr Neurol. Sept 2017; 74:87-91.e2. https//www.ncbi.nlm.nih.gov/pubmed/28662915.