Fourteen cases of cerebral creatine deficiency syndrome in children: a cohort study in China

BACKGROUND: This study sought to analyze the clinical characteristics, biochemical metabolic indications, treatment results, and genetic spectrum of cerebral creatine deficiency syndrome (CCDS), estimate the prevalence of CCDS in Chinese children and provide a reference to guide clinical practice. METHODS: We performed a retrospective cohort study of 3,568 children with developmental delay at Children’s Hospital of Fudan University over a 6-year period (January 2017–December 2022). Metabolites in the blood/urine were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and genetic testing was performed by next-generation sequencing (NGS). The patients with suspected CCDS were ultimately diagnosed by magnetic resonance spectroscopy (MRS). The patients were then treated and followed up. All the reported cases of CCDS, their gene mutations, and treatment results in China were summarized. RESULTS: Ultimately, 14 patients were diagnosed with CCDS. The age of onset was between 1–2 years. All the patients had developmental delay, 9 had epilepsy, and 8 had movement or behavioral disorders. A total of 17 genetic variants were identified, including 6 novel variants. c.403G>A, c.491dupG of the guanidinoacetate methyltransferase (GAMT) gene had a relatively high frequency. After treatment, patients with GAMT deficiency showed obvious improvements, and brain creatine (Cr) levels recovered to 50–80% of normal, 1 patient achieved normal neurodevelopment, and 3 patients became epilepsy free; however, 6 male patients with X-linked creatine transporter gene (SLC6A8) variants received Cr for 3–6 months with no effect, and 2 patients received combined therapy with few improvements. CONCLUSIONS: The prevalence of CCDS is ~0.39% in Chinese children with developmental delay. A low-protein diet, Cr and, ornithine were useful for patients with GAMT deficiency. Male patients with SLC6A8 deficiency showed only limited improvement on combined therapy.