GALT rs111033624: Understanding the Duarte Variant
The rs111033624 variant in the GALT gene, commonly known as the p.Asn314Asp or N314D mutation, is a genetic change associated with the Duarte variant of galactosemia. While often considered benign when present in isolation, it is monitored in clinical settings for its potential to interact with other GALT mutations.
What each genotype means
Typical enzyme activity
You carry two copies of the common reference allele at this position in the GALT gene. This genotype is associated with normal baseline galactose-1-phosphate uridylyltransferase activity and does not indicate carrier status for the Duarte 2 (D2) hypomorphic allele. In the absence of other pathogenic mutations, this result confers standard galactose processing.
Carried by approximately 85% to 90% of individuals of European descent and over 95% of individuals of East Asian or African ancestry.
Duarte 2 carrier
You have one copy of the Duarte 2 (D2) variant, which typically yields around 75% of baseline GALT enzyme function on its own. While single carriers usually do not experience metabolic symptoms, research notes potential clinical relevance if combined in trans with a classical galactosemia mutation (forming compound heterozygous Duarte galactosemia). The evidence connecting isolated heterozygous status to diminished ovarian reserve remains limited and inconclusive.
Carried by roughly 10% to 14% of people of European ancestry, but present in less than 3% of East Asian populations.
Duarte 2 homozygote
You carry two copies of the Duarte 2 (D2) variant, which typically reduces overall GALT enzyme activity to approximately 50% of reference levels. Homozygous Duarte individuals generally process galactose adequately without developing classic galactosemia symptoms, though reproductive and carrier panels sometimes monitor this genotype. Current scientific evidence regarding long-term impacts on ovarian function or fertility is limited, with studies largely showing no clear adverse clinical outcome.
Found in less than 1% of individuals across most global populations, occurring most frequently in populations of European descent.
What is the rs111033624 Variant?
The rs111033624 variant is a single nucleotide polymorphism (SNP) located within the GALT gene, which provides instructions for making the enzyme galactose-1-phosphate uridylyltransferase. In scientific literature, this specific change is frequently referred to as p.Asn314Asp or N314D, indicating that the amino acid asparagine has been replaced by aspartic acid at position 314 of the protein. This variant is a key component of what is known as the Duarte 2 (D2) haplotype, a group of genetic changes that often occur together on the same chromosome. Because it is a common variant, it is frequently identified during newborn screening programs. While historically labeled as pathogenic in some contexts, modern research often classifies the variant itself as having unclear or benign clinical significance when found alone, as it is frequently found in healthy individuals.
The Role of the GALT Gene
The GALT gene is essential for the body's ability to process galactose, a simple sugar found in milk and other dairy products. The enzyme produced by this gene, galactose-1-phosphate uridylyltransferase, performs a critical step in converting galactose into glucose, which the body uses for energy. When the GALT gene is significantly impaired, galactose can build up to toxic levels, leading to a condition called classic galactosemia. The Duarte variant is distinct because it does not completely eliminate the enzyme's activity. Instead, it typically results in a partial reduction of enzyme function, often retaining 5% to 20% of normal activity. Because some function remains, individuals with the Duarte variant generally experience much milder symptoms compared to those with classic galactosemia, and many remain asymptomatic throughout their lives.
Research and Clinical Associations
Research into rs111033624 focuses heavily on its interaction with other, more severe GALT mutations. Clinical concern arises when an individual inherits the Duarte variant from one parent and a severe, loss-of-function GALT mutation from the other. This combination, known as compound heterozygosity, can lead to Duarte galactosemia. In these cases, the residual activity provided by the Duarte allele is insufficient to prevent the accumulation of galactose metabolites, leading to milder clinical features than those seen in classic galactosemia. Because of this, the variant is monitored in clinical genetics to assess the risk of galactosemia in newborns. However, when the variant is present in isolation, it is generally not associated with significant health complications. Studies have also investigated potential links to other conditions, such as ovarian cancer, but current evidence has not established a clear or significant association.
Population Frequency
The rs111033624 variant is relatively common, particularly in populations of European descent, where the allele frequency is estimated to be between 5% and 9%. It is also observed in other populations, though frequencies vary significantly; for instance, some data suggests higher frequencies in certain South Asian cohorts. Because it is a common variant, it is frequently detected in large-scale genomic databases like gnomAD. The prevalence of the Duarte variant is estimated to be approximately ten times higher than that of classic galactosemia, making it a frequent finding in newborn screening programs. Its widespread presence in the general population supports the understanding that, in the absence of other severe GALT mutations, this variant is typically compatible with normal health and development.
Interpreting Your Information
If you have received information regarding your status for the rs111033624 variant, it is important to understand that this is a common genetic finding. In many cases, carrying this variant does not result in any health issues. This information is not a medical diagnosis and should not be used to make decisions about your diet or health. If you are concerned about your GALT status or have questions about newborn screening results, you should consult with a qualified healthcare provider or a genetic counselor. They can help interpret your results in the context of your personal and family health history. If you are taking any medications or have specific dietary concerns, always discuss these with your clinician or a registered dietitian before making any changes to your lifestyle or medical management.
How common is this variant?
The rs111033624 variant is common in European populations with a minor allele frequency of approximately 5% to 9%, while it is less frequent in East Asian populations.
Frequently asked questions
Is the Duarte variant the same as classic galactosemia?
No, the Duarte variant is distinct from classic galactosemia. While classic galactosemia involves a severe deficiency of the GALT enzyme, the Duarte variant typically results in only a partial reduction of enzyme activity and generally causes much milder or no symptoms.
What should I do if I am a carrier of the Duarte variant?
Being a carrier of the Duarte variant is a common finding and is often considered benign. You should discuss your results with a healthcare provider or genetic counselor who can provide context based on your specific health history.
Does the Duarte variant require a special diet?
In most cases, individuals with the Duarte variant do not require a special diet. However, medical management is determined by a clinician based on individual enzyme activity levels and clinical symptoms.
Can the Duarte variant cause health problems later in life?
When present in isolation, the Duarte variant is generally not associated with long-term health complications. Clinical monitoring is typically reserved for cases where it is inherited alongside other, more severe GALT mutations.
Sources & further reading
Educational information only, last refreshed 10/28/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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