[Identification of two novel SLC19A3 variants in a Chinese patient with Biotin-thiamine responsive basal ganglia disease].

OBJECTIVE: To explore the genetic basis for a neonate featuring global developmental delay. METHODS: Clinical and laboratory tests were carried out for the patient. Peripheral venous blood samples were collected from the neonate and his parents for the extraction of DNA. Potential variant was detected by using targeted capture and next generation sequencing for a panel of genes associated with nervous system diseases. Suspected variant was validated by Sanger sequencing. RESULTS: The nine-month-old boy manifested global developmental delay and was unstable to sit alone and distinguish strangers from acquaintance. Genetic testing revealed two novel variants of the SLC19A3 gene in him, namely c.448G>A and c.169C>T. The amino acids encoded by the two codons are highly conservative, and both variants were predicted to be pathogenic by bioinformatic analysis. CONCLUSION: The compound heterozygous c.448G>A and c.169C>T variants probably underlay the onset of disease in the patient. Above finding also enriched the variant spectrum of SLC19A3 gene underlying Biotin-thiamine responsive basal ganglia disease.