Neonatal Nonketotic Hyperglycinemia: A Rare Case from Pakistan

Nonketotic hyperglycinemia (NKH) is an autosomal recessive disorder caused by a defect in glycine cleavage enzyme. It leads to the accumulation of glycine in the body tissues, blood, and cerebrospinal fluid (CSF). Most NKH cases are diagnosed during the natal period of life and are fatal if not promptly diagnosed and managed. Here we present a case of a two-day-old child who presented with reluctant feeding and lethargy. She had reduced tone in all four limbs and a Glasgow Coma Scale score of 9. Keeping an infectious etiology in mind, she was started on cefotaxime and amikacin. The patient was shifted to the neonatal intensive care unit; however, no improvement in the patient's condition was seen and antibiotics were changed to linezolid and meropenem along with initiation of acyclovir. The patient's blood and CSF cultures were negative. Serum amino acid chromatography showed elevated levels of glycine, and a diagnosis of NKH was made. The patient was managed symptomatically but expired on the 22nd day of admission. The case highlights the importance of prompt diagnosis and management of aminoacidopathies. Nearly all metabolic disorders have similar clinical presentations, and an early diagnosis can improve the outcome in patients.