Genetic analysis and treatment for an infant with cerebral creatine deficiency syndrome type 2

OBJECTIVE To carry out genetic and metabolite analysis for an infant with cerebral creatine deficiency syndrome type 2 (CCDS2). METHODS Clinical data of the child was collected. Whole-exome sequencing was carried out to identify potential variants by next generation sequencing. Candidate variants were confirmed by Sanger sequencing. Metabolites were determined by tandem mass spectrometry and magnetic resonance spectroscopy. Treatment was carried out following the diagnosis and genetic counseling for the affected family. RESULTS Two novel heterozygous variants (c.289delC and c.392-1G>C) of the GAMT gene were identified in the proband, which were respectively inherited from her father and mother. In silico analysis suggested both variants to be pathogenic. Creatine (Cr) level of the child was very low, and cerebral guanidinoacetate (GAA) level was slightly increased. But both had recovered to normal in two weeks, and cerebral Cr level was significantly improved after two months. Intellectual and motor development of the child were significantly improved. CONCLUSION The child was diagnosed with CCDS type 2, for which pathogenic variants of the GAMT gene may be accountable. Treatment has attained a satisfactory effect for the patient.