Galactose (urine) | Laboratory research

Galactose is a sugar found in milk (including breast milk).

Galactosemia is a rare genetic disease in which, due to the deficiency of enzymes involved in galactose metabolism, the process of converting galactose into glucose is disrupted, followed by an increase in the concentration of galactose in the blood.

The disease is quite rare, 1 case occurs in about 45000 people.

Timely diagnostics of the disease is important, because galactosemia causes life-threatening complications in newborns.

As the concentration of galactose in the blood increases, alternative decomposition processes begin. As a result, galactose is transformed into galactitol, which is an organic alcohol derivative, very toxic and damages tissues and organs. Without treatment, galactosemia is accompanied by such complications as:

• Cataract
• Impairment of physical and mental development
• speech disorder
• Violation of gross and fine motor skills
• Various neurological pathologies
• Kidney diseases
• Ovarian dysfunction
• Liver failure
• sepsis and others

Against the backdrop of early disease diagnostics and timely treatment, the child grows and develops normally. However, small deviations may still be observed, because despite limiting galactose in the diet, it cannot be completely removed, besides, a small amount of galactose is synthesized endogenously in our body. Despite treatment, children with galactosemia often have:

• Delay in speech development
• learning difficulties
• behavioral disorders
• balance problems (ataxia)
• Tremor
• Lack of sex hormones, especially in girls, due to which pubertal processes are delayed

As adults, people with galactosemia may lead normal lives, but symptoms seen in childhood persist throughout life. Depending on the control of the diet, the symptoms may be expressed in different intensities. Manifestations such as complications associated with hormone deficiency are persistent despite treatment.

Symptoms

Classical signs of galactosemia in newborns begin to appear a few days after birth:

• Loss of appetite
• Drowsiness
• Vomiting
• Diarrhea
• Rapid weight loss
• weakness
• Jaundice
• Abdominal bloating and sometimes ascites (accumulation of fluid)
• neurological disorders

These signs require urgent medical intervention.

There are three clinical types of galactosemia:

Type I

Classical galactosemia is more frequent and severe than cheese. It is caused by a mutation in the GALT gene. This gene is involved in the synthesis of the enzyme - galactose-1-phosphate uridylyl transferase, through which galactose is transformed into glucose and is involved in the process of energy production. In the case of enzyme deficiency, galactose quickly accumulates in the blood, is broken down in an alternative way, and the toxic effects of metabolites are revealed.

Type II

A mutation in the GALK1 gene leads to the development of type II galactosemia. The mutation of the mentioned gene causes a deficiency of the enzyme galactokinase, which is important in the metabolism of galactose. This form is less characterized by symptoms of classical galactosemia. Cataract formation is typical.

Type III

As a result of the mutation of the GALE gene, it is the result of a deficiency of the enzyme - galactose epimerase. The Gase enzyme converts modified galactose into a modified form of glucose. Its deficiency leads to the accumulation of galactose in the blood. Symptoms can be manifested in different degrees. In severe cases, the same complications that characterize classic galactosemia (development delay, cataracts, liver and kidney pathologies) are frequent.

Duarte's galactosemia

It is the result of a mutation in the GALT gene, as in classical (type I) galactosemia. In this form, enzyme deficiency is expressed to a lesser degree. People with Duarte's galactosemia have mild discomfort when consuming milk and dairy products, but complications do not develop at this time. It is not necessary to exclude galactose from the diet.

Diagnosis

Screening for genetic metabolic diseases, including galactosemia, is an accepted practice for disease diagnostics in many countries. Both blood from the newborn's heel and urine can be used for screening. The study is conducted at least 24-48 hours after birth. In case of a positive answer, genetic research is necessary to identify the mutation and, accordingly, the type of disease.

Disease management and treatment

The only method of treating galactosemia is to exclude galactose-containing products from the diet, which means limiting milk and dairy products. In children and adults, it is often necessary to determine calcium and vitamin D and provide them as supplements to prevent deficiency.

In children, with complications of galactosemia, additional intervention in the form of occupational, behavioral, and speech therapies is often necessary.

In female patients during puberty, it is necessary to study sex hormones and hormone replacement therapy to prevent ovarian failure.

Adults diagnosed with galactosemia do not require special intervention, however, periodic visits to the doctor are necessary for early detection of possible complications, such as: cataracts, neurological disorders (tremors, ataxia), osteoporosis, hormonal disorders, and others.

Galactosemia is a rare but genetic screening-predictable disease. Prenatal screening of pregnant women provides the opportunity to detect a number of genetic diseases.

Postnatal extended screening of newborns is also important for timely diagnostics of the disease and appropriate measures.