G6PD = glucose-6-phosphate dehydrogenase deficiency.
GABA = gamma-aminobutyric acid.
Galactosaemia A condition which usually becomes evident in early infancy when the baby starts to vomit and is reluctant to feed. Lethargy, weight loss and jaundice follow. It is caused by deficiency of an enzyme necessary to convert galactose (found in milk) and galactose-1-phosphate to glucose in the body. As a result there is an accumulation of chemicals in the blood which damage the liver, kidneys, lens of the eye and brain. Galactose and a number of amino acids appear in the urine. If the condition is untreated liver damage, mental handicap and cataracts develop and death occurs early. If treated with a lactose-free diet soon after birth, physical health recovers and mental handicap may be prevented or reduced in severity. This condition is inherited from both parents who are carriers (recessive inheritance). The diagnosis may be made before birth using cells obtained by amniocentesis. The carrier state can also be detected from fibroblast culture. There are some rarer forms of this condition in which the person is less severely affected.