SNP Shot: Genomic Insights

Deoxyguanosine kinase (dGK) deficiency is a genetic condition that can lead to liver disease and neurological issues. There are two known types of dGK deficiency. The more common and severe type is known as the hepatocerebral form because it significantly impacts both the liver and the brain.

Infants born with the hepatocerebral form of dGK deficiency may develop lactic acidosis (a buildup of lactic acid) shortly after birth. Other early symptoms can include weakness, changes in behavior such as difficulty feeding and reduced activity, and vomiting. Some affected newborns experience low blood sugar (hypoglycemia) due to liver problems. Within the first few weeks of life, they start to show other signs of liver disease that can lead to liver failure. They also develop worsening neurological problems, including very poor muscle tone (severe hypotonia), involuntary eye movements (nystagmus), and loss of previously learned skills (developmental regression). Sadly, children with this severe form usually do not live beyond two years of age.

A milder form of dGK deficiency exists, where individuals do not experience severe neurological issues. In this form, liver disease is the main symptom, typically appearing in infancy or childhood. Sometimes, the liver problems first become apparent after an illness, such as a viral infection. Kidney problems can also occur in these individuals. Mild hypotonia is the only neurological symptom associated with this less severe form.

Inheritance:

dGK deficiency follows an autosomal recessive inheritance pattern. This means that a person must inherit two copies of the mutated gene (one from each parent) to develop the condition. The parents, who each carry only one copy of the mutated gene, are usually unaffected by the condition.