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.
Congenital and Genetic Diseases; Newborn Screening
Galactosemia, which means “galactose in the blood,” refers to a group of
- Classic galactosemia (type 1) the most common and severe type, caused by mutations in the GALT gene, and characterized by a complete deficiency of an enzyme called galactose-1-phosphate uridyl
transferase(GALT). Early signs and symptoms include liver dysfunction, susceptibilityto infections, failure to thrive, and cataracts. These can usually be prevented or improved by early diagnosis and treatment, but other progressive or long-term problems are common despite treatment. These include intellectual deficits, movement disorders, and premature ovarian failure (in females).
- Galactokinase deficiency (type 2) caused by mutations in the GALK1 gene and characterized by a deficiency of the enzyme galactokinase 1. This type typically causes only the development of cataracts, which may be prevented or resolved with treatment. Rarely, this type causes pseudotumor cerebri (a condition which mimics the symptoms of a large brain
tumorwhen no brain tumor is present).
- Galactose epimerase deficiency (type 3) caused by mutations in the GALE gene and characterized by a deficiency of the enzyme UDP-galactose-4-epimerase. Symptoms and severity of this type depend on whether the deficiency is confined to certain types of blood
cellsor is present in all tissues. Some people with this type have no signs or symptoms, while others have symptoms similar to those with classic galactosemia. Like in classic galactosemia, many symptoms can be prevented or improved with treatment.
There is also a "variant" of classic galactosemia called Duarte variant galactosemia, in which a person has mutations in the GALT gene but has only partial deficiency of the enzyme. Infants with this form may have
Inheritance of all types of galactosemia is
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|
Abnormality of cognition
[ more ]
|Failure to thrive in infancy||
Faltering weight in infancy
Weight faltering in infancy
[ more ]
|Feeding difficulties in infancy||0008872|
Mental retardation, nonspecific
[ more ]
Yellowing of the skin
[ more ]
|Nausea and vomiting||0002017|
|30%-79% of people have these symptoms|
|Abnormality of coagulation||0001928|
|Abnormality of the voice||
Accumulation of fluid in the abdomen
Clouding of the lens of the eye
[ more ]
[ more ]
Low or weak muscle tone
Fluid accumulation in lower limbs
Lower leg swelling
[ more ]
Infection in blood stream
|5%-29% of people have these symptoms|
Difficulty articulating speech
Low blood sugar
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference
[ more ]
Renal failure in adulthood
[ more ]
Loss of eyesight
[ more ]
Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.
- The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
- The Newborn Screening Coding and Terminology Guide has information on the standard codes used for
newborn screeningtests. Using these standards helps compare data across different laboratories. This resource was created by the National Library of Medicine.
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.
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 was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
- Genetics Home Reference (GHR) contains information on Galactosemia. 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 Screening, Technology And Research in Genetics (STAR-G) Project has a fact sheet on this condition, which was written specifically for families that have received a diagnosis as a result of newborn screening. This fact sheet provides general information about the condition and answers questions that are of particular concern to parents.
- 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.
Classic Galactosemia and Clinical Variant Galactosemia
Epimerase deficiency galactosemia
Duarte Variant Galactosemia
- 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 Galactosemia. Click on the link to view a sample search on this topic.
- Galactosemia. Genetics Home Reference. August, 2015; https://www.ghr.nlm.nih.gov/condition=galactosemia.
- Galactokinase deficiency. Baby's First Test. https://www.babysfirsttest.org/newborn-screening/conditions/galactokinase-deficiency. Accessed 10/9/2018.
- Sutton VR. Galactosemia: Clinical features and diagnosis. UpToDate. Waltham, MA: UpToDate; July 18, 2018; https://www.uptodate.com/contents/galactosemia-clinical-features-and-diagnosis.
- Pseudotumor Cerebri Information Page. National Institute of Neurological Disorders and Stroke (NINDS). June 20, 2018; https://www.ninds.nih.gov/Disorders/All-Disorders/Pseudotumor-Cerebri-Information-Page.
- Fridovich-Keil J, Bean L, He M, Schroer R. Epimerase Deficiency Galactosemia. GeneReviews. June 16, 2016; https://www.ncbi.nlm.nih.gov/books/NBK51671/.
- Sutton VR. Galactosemia: Management and outcome. UpToDate. Waltham, MA: UpToDate; March 13, 2017; https://www.uptodate.com/contents/galactosemia-management-and-outcome.
- Fridovich-Keil J, Gambello MJ, Singh RH, Sharer JD. Duarte Variant Galactosemia. GeneReviews. December 4, 2014; https://www.ncbi.nlm.nih.gov/books/NBK258640/.