Classic Galactosemia is a rare genetic metabolic disorder. The child with classic galactosemia inherits a gene for galactosemia from both parents, who are carriers. Patients who inherit the classic galactosemia gene from each parent are sometimes described as having the genetic makeup "G/G". Normally when a person consumes a product that contains lactose (e.g., dairy products such as milk, cheese, butter), the body breaks the lactose down into galactose and glucose. Glucose is the sugar used by the body for energy. Galactosemia means too much galactose in the blood caused by the individual "missing" the enzyme (known as GALT) to convert galactose into glucose. This accumulation of galactose is a poison to the body and can cause serious complications such as the following and if untreated, as high as 75% of infants will die:
Diagnosis is made usually within the first week of life by blood test from a heel prick as part of a standard newborn screening. Treatment requires the strict exclusion of lactose/galactose from the diet. Although galactosemic children are started on diet restriction at birth, there continues to be a high incidence of long-term complications involving speech and language, fine and gross motor skill delays and specific learning disabilities. Ovarian failure may occur in girls. Prenatal diagnosis by amniocentresis is also available.
Sufferers of galactosemia have cataracts. A cataract is a clouding of the lens of the eye. The lens is a crystal-clear, flexible structure near the front of the eyeball. It helps to keep vision in focus, and screens and refracts light rays. The lens has no blood supply. It is nourished by the vitreous (the watery substance that surrounds it). Cataracts may form in one or both eyes. If they form in both eyes, their growth rate may be very different. Cataracts are not cancerous.
Appropriate health care includes treatment by an ophthalmologist or surgery to remove the lens.
Cataracts are one of the possible complications of classic galactosemia. Cataracts are mostly observed in newborns but can also occur in adults. It is thought that 10-30% of newborns with classic galactosemia develop cataracts in the first few days or weeks of life. Once a newborn is put on a galactose-restricted diet, cataracts usually clear up on their own. Surgery is sometimes necessary in rarer cases.
It is believed that if the galactose restricted diet is followed, cataracts do not develop in galactosemic children.
Many patients have eye examinations to check for the presence of cataracts on a regular basis. More frequent during the first year of life (e.g every 3-4 months), such exams can be reduced in frequency (e.g. 1 or 2 times a year) in older children. It is a good idea to have an eye exam if for some reason Gal-1-P levels are observed to rise above a 'target' range.
Treatment for galactosemia is the elimination of galactose and lactose from the diet throughout life. A person with galactosemia will never be able to properly digest foods containing galactose. There is no chemical or drug substitute for the missing enzyme at this time. An infant diagnosed with galactosemia will simply be changed to a soy-based formula that does not contain galactose. Galactosemia is often confused with lactose intolerance, but please keep in mind that galactosemia is a disease. A person with galactosemia will not "grow out of" it.