Valinemia is a very rare metabolic disorder characterized by abnormally high levels of the amino acidvaline in the blood and urine. Infants with valinemia reportedly experience lack of appetite, vomiting, and failure to thrive. In some cases, the condition may be life-threatening. Low muscle tone (hypotonia), excessive drowsiness, hyperactivity, and developmental delay have also been reported. Valinemia is caused by a deficiency of the enzyme valine transaminase, which is needed for the breakdown (metabolism) of valine in the body. It is inherited in an autosomal recessive manner, although the gene responsible for the condition is not yet known. Treatment includes a diet low in valine (introduced during early infancy) which usually improves symptoms and brings valine levels to normal.

Valinemia is thought to be extremely rare and has been described in only a few people. The condition is reportedly present from birth. Symptoms in the newborn period include lack of appetite, protein intolerance, metabolic acidosis, frequent vomiting, failure to thrive, and/or coma. The condition can become life-threatening. Abnormally low muscle tone (hypotonia); hyperkinesia; hyperactivity; excessive drowsiness; and delayed mental and physical development have also been reported.

Due to the rarity of valinemia, information about treatment in the medical literature is very limited. A diet low in valine introduced during early infancy is thought to improve symptoms of the condition and lower valine concentrations in the blood to normal levels.