title: Sequential magnetic resonance spectroscopic changes in a patient with nonketotic hyperglycinemia.
abstract: Nonketotic hyperglycinemia (NKH) is a rare inborn error of amino acid metabolism. A defect in the glycine cleavage enzyme system results in highly elevated concentrations of glycine in the plasma, urine, cerebrospinal fluid, and brain, resulting in glycine-induced encephalopathy and neuropathy. The prevalence of NKH in Korea is very low, and no reports of surviving patients are available, given the scarcity and poor prognosis of this disease. In the current study, we present a patient with NKH diagnosed on the basis of clinical features, biochemical profiles, and genetic analysis. Magnetic resonance spectroscopy (MRS) allowed the measurement of absolute glycine concentrations in different parts of the brain that showed a significantly increased glycine peak, consolidating the diagnosis of NKH. In additional, serial MRS follow-up showed changes in the glycine/creatinine ratios in different parts of the brain. In conclusion, MRS is an effective, noninvasive diagnostic tool for NKH that can be used to distinguish this disease from other glycine metabolism disorders. It may also be useful for monitoring NKH treatment.
authors.affiliation: Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Ji Hun
authors.initials: JH
authors.lastname: Shin
authors.forename: So Yoon
authors.initials: SY
authors.lastname: Ahn
authors.forename: Jeong Hee
authors.initials: JH
authors.lastname: Shin
authors.forename: Se In
authors.initials: SI
authors.lastname: Sung
authors.forename: Ji Mi
authors.initials: JM
authors.lastname: Jung
authors.forename: Jin Kyu
authors.initials: JK
authors.lastname: Kim
authors.forename: Eun Sun
authors.initials: ES
authors.lastname: Kim
authors.forename: Hyung Doo
authors.initials: HD
authors.lastname: Park
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Kim
authors.forename: Yun Sil
authors.initials: YS
authors.lastname: Chang
authors.forename: Won Soon
authors.initials: WS
authors.lastname: Park