Pre-therapy and post-therapy MRI and MRS findings in non-ketotic hyperglycinemia

Abstract

Non-ketotic hyperglycinemia (NKH) is an uncommon metabolic disorder with an autosomal recessive inheritance due to abnormal glycine metabolism. We present the pre-therapy and post-therapy magnetic resonance imaging, biochemical and clinical features of a child with NKH with manifestation in the early neonatal period. The initial diagnosis of NKH was made on the biochemical evidence of elevated cerebrospinal fluid (CSF) glycine levels and CSF: plasma glycine ratio. Pre-therapy magnetic resonance imaging revealed thinned out corpus callosum, intracranial hemorrhages, prominent ventricular system, few cystic changes in bilateral gangliocapsular region and abnormal T2 hyperintensities in the white matter. Magnetic resonance spectroscopy did not reveal glycine peak in our case. Post-therapy, there was clinical improvement and reduction in CSF glycine levels. In the follow up scan, myelination had progressed with residual leukomalacic changes and volume loss of white matter.