Congenital Hyperglycinemia; Demonstration of a Minor Metabolic Defect in the Parents.

Idiopathic hyperglycinemia, first discovered by Childs et al.,l is thought to be an inherited metabolic disorder, because of onset of the clinical symptoms and presence of metabolic anomaly in the early period of life and probable familial occurrence of the disorder.1-3 In our preceding studies on this particular disorder,4 the following results were obtained: 1) The fasting serum level of glyeine was found to be slightly but significantly higher in the parents of a patient with hyperglycinemia than in controls. 2) In oral glycine loading test (0.5 g/kg), the parents showed significantly higher levels of serum glycine at 1. 2 and 3 hours following the test dose as com pared with those of controls. These results suggested that the parents were heterozygous for the disorder. Basing upon these results, we have suggested that the term "congenital hyperglycinemia" is more appropriate for this disorder rather than "idiopathic hyperglycinemia. 3,4 In this paper, further evidence of heterozygosity will be reported.