Galactosemia
Galactosemia is also a metabolic enzyme deficiency/absence condition which is transmitted through a recessive genetic trait. Riordan and Auerbach state the incidence of galactosemia as one in every 85,000 births or about 47 infants per year in the US. Infants lacking a critical liver enzyme (responsible for converting galactose to glucose) risk severe mental retardation and liver damage. The symptoms of galactosemia are vague, especially since the newborn appears normal.
However, soon after birth mothers report that their infants have profuse vomiting, poor weight gain, wasting and lethargy. This usually prompts them to seek medical attention and testing (or perhaps phone La Leche League first). As stated in the BREASTFEEDING ANSWER BOOK, page 308, this enzyme is heat-sensitive and results may be skewed if the sample sits in a hot mailbox. Failing to identify galactosemia may have dire results while false-positive test results can lead to unnecessary weaning. Practitioners often err on the side of weaning when there is doubt. Thus, mothers should be encouraged to request an immediate retest with special handling. Such testing may be difficult in areas where there is no reliable way of protecting the sample from heat. There is no intermediate or partial breastfeeding option for these infants. They must be totally weaned promptly and fed a galactose-free formula such as Nutramigen. A bottle or cup must be used; use of a supplemental nursing system is not possible because it could allow ingestion of human milk. Note that this is a very different situation than PKU, so a clear diagnosis is critical.