Two Novel GLDC Mutations in a Neonate with Nonketotic Hyperglycinemia.
Nonketotic hyperglycinemia, also known as glycine encephalopathy (OMIM #605899), is an autosomal recessive disorder of glycine metabolism resulting from a defect in the glycine cleavage system. We report two novel mutations of the glycine decarboxylase (GLDC) gene observed in a compound heterozygous state in a neonate of mixed Maori and Caucasian parentage: c.395C>T p.(Ser132Leu) in exon 3, and c.256-?_334+?del p.(Ser86Valfs*119), resulting in an out-of-frame deletion of exon 2. Additionally, we describe our experience of implementing the ketogenic diet, alongside standard pharmacological therapy, and highlight its potential therapeutic benefit in severe nonketotic hyperglycinemia, particularly in seizure management.
Diagnostic Genetics, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
Sarah L
SL
Nickerson
Metabolic Unit, Department of Rheumatology/Metabolic Medicine, Princess Margaret Hospital, Perth, WA, Australia; School of Paediatrics and Child Health, University of Western Australia, WA, Australia.
Shanti
S
Balasubramaniam
Diagnostic Genetics, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
Philippa A
PA
Dryland
Diagnostic Genetics, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
Jennifer M
JM
Love
School of Paediatrics and Child Health, University of Western Australia, WA, Australia; Department of Paediatric Neurology, Princess Margaret Hospital for Children, Perth, WA, Australia.
Maina P
MP
Kava
Diagnostic Genetics, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
Donald R
DR
Love
Diagnostic Genetics, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
Debra O
DO
Prosser
GLDC gene; glycine decarboxylase; glycine metabolism; ketogenic diet; nonketotic hyperglycinemia