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Genetics Library / Genes / GALK1

GENE REFERENCE / HGNC:4118

GALK1

galactokinase 1

protein-coding gene17q25.1Gene information

What does this gene do?

The GALK1 gene provides instructions for making an enzyme called galactokinase 1. This enzyme enables the body to process a simple sugar called galactose, which is present in small amounts in many foods. Galactose is primarily part of a larger sugar called lactose, which is found in all dairy products and many baby formulas.

Galactokinase 1 is responsible for one step in a chemical process that converts galactose into other molecules that can be used by the body. Specifically, this enzyme modifies galactose to create a similar molecule called galactose-1-phosphate. A series of additional steps converts galactose-1-phosphate to another simple sugar called glucose, which is the main energy source for most cells. Galactose-1-phosphate can also be converted to a form that is used to build galactose-containing proteins and fats. These modified proteins and fats play critical roles in chemical signaling, building cellular structures, transporting molecules, and producing energy.

Source: MedlinePlus, National Library of Medicine. Source publication: 2020-08-18. Source review: 2008-01.

Related condition topics

MedlinePlus mentions this gene in the condition pages below. These links alone do not show that the gene causes a condition.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

ConditionInheritanceEvidence
galactokinase deficiencyMONDO:0009255 · Evaluated 2021-09-30Autosomal recessiveDefinitiveGeneral Inborn Errors of Metabolism Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles
1,207
Submissions for variants in or overlapping this gene
1,813
Submissions explicitly reporting this gene
887
Alleles reported pathogenic / likely pathogenic
189
VariationIDs with uncertain significance
331
VariationIDs with conflicting classifications
21

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about GALK1?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 189 alleles in GALK1 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in GALK1.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

Sources and dates

The source information on this page last changed on 2026-10-17.

HGNC Source details

Open source record ↗

Source release: Fri, 16 Oct 2026 13:36:12 GMT
Source record updated: 2023-01-20

SHA-256: 72bfe0c05800163c040a2cf663c70501f9ac9236469fbd0b552f2cd37a4d7f67

MedlinePlus Source details

Open source record ↗

Source release: Sat, 17 Oct 2026 05:15:49 GMT
Source publication: 2020-08-18
Source review: 2008-01

SHA-256: fdc8bd614310c12718379cef6569962e5d0e791cecabcc355b53a72816ac263a

ClinVar Source details

Open source record ↗

Source release: Sun, 11 Oct 2026 06:36:01 GMT

SHA-256: b21584f8ebc89a636ce9706023fa9052460587e2ab0fe6d0edf4b9db34336c02

ClinGen Source details

Open source record ↗

Source release: Sat, 17 Oct 2026 07:46:29 GMT

SHA-256: 46d4c75fcae7dd62a9dea4988bbbd440bdc68f2db452fea1556d47b0406de60e

About the library sources · Latest validated release · Record f11ab0593c18