[P3-74] Clinical and molecular genetic study of nonketotic hyperglycinemia in a Chinese family
Nonketotic hyperglycinemia (NKH) is a rare, inborn errors of metabolism. In this case report, a Chinese male infant was diagnosed with nonketotic hyperglycinemia caused by GLDC gene mutation. The clinical characteristics and the genetic defects were investigated. The infant presented with an onset of early metabolic encephalopathy and Ohtahara syndrome. Both blood and urinary levels of metabolites were in the normal range. Brain MRI images indicated a poor development of corpus callosum, and a burst suppression pattern was found in the EEG. Results of target gene sequencing technology combined with other methods of molecular genetics identified a heterozygous missense mutation of c.1786 C> T (p.R596X) in maternal exon 15 and a loss of heterozygosity of 4-15 exon gross deletions in paternal GLDC gene. These definite pathogenic mutations confirmed the diagnosis of nonketotic hyperglycinemia. The infant's clinical condition was not improved after treatment with ACTH, topiramate and dextromethorphan, and finally died at 4 month of age. Patients with nonketotic hyperglycinemia often exhibit complicated clinical phenotypes; and are lack of specific symptoms. NKH could be diagnosed by using metabolic screening and molecular genetic analysis.