Glyceryl phenylbutyrate in the treatment of argininosuccinate synthetase deficiency: a case report / 中华实用儿科临床杂志

ABSTRACT

Clinical data of a child with high blood ammonia and suspected argininosuccinate synthetase deficiency (ASSD) in Hunan Children′s Hospital were retrospectively analyzed, including data of mass spectra for blood amino acids and acyl carnitine, urine organic acid analysis and whole exome sequencing.After the exact diagnosis of ASSD and being approved by the Administrative Regulation for Import Medical Devices Urgently Needed in Boao Lecheng International Medical Tourism Pilot Zone of Hainan Free Trade Port, the patient was medicated with Glyceryl phenylbutyrate (GPB) and followed up.The patient was a boy aged 7 years and 8 months, who presented at the Neurology Department of Hunan Children′s Hospital for sleepiness, abnormal mental behavior and personality change for 1 week on December 2, 2021.Before GPB treatment, the highest blood ammonia, alanine aminotransferase and aspartate transaminase were 325.2 μmol/L, 465.7 IU/L and 277.3 IU/L, respectively.Genetic metabolism assay of blood and urine showed a significantly increased citrulline at 697.42 μmol/L; urine organic acid analysis showed increased urinary orotic acid at 144.2 μmol/L, and increased uracil at 65.1 μmol/L.A pure heterozygous variant of the ASS1 gene (c.1087C>T, p.R363W) was detected.After GPB treatment, the blood ammonia levels were 21.3 μmol/L, 54.6 μmol/L and 62.4 μmol/L on the 41 st, 90 th and 146 th days, respectively.Until July 20, 2022 follow-up visit, the patient recovered well without adverse events.This was the first ASSD child in China who was treated with GPB.This case report provided therapeutic experience of ASSD in our country.ASSD has a high mortality rate and unexplained abnormal mental behavior.It is necessary to timely measure blood ammonia, and a series of urea cycle disorders should be well concerned.The diagnosis and management of ASSD rely on the data of metabolism examination and genetic testing.