Abstract: Objective To explore the clinical phenotypic and genetic characteristics of aromatic L-amino acid decarboxylase deficiency (AADCD). Methods The clinical data of one family with AADCD were retrospectively analyzed, and the relevant literature was reviewed. Results The two siblings in the family all had onset at 3 months of age, and the main manifestations were eye movement crisis, developmental retardation, hypotension and hyperhidrosis. A compound heterozygous variants of c. 714 + 4 (IVS 6 ) A>T and c. 1234 (exon 13 ) C>T in DDC gene were detected by whole exon sequencing, and the former originated from father and the latter originated from mother. Conclusion The clinical phenotype of AADCD with compound heterozygous variants of c.714 + 4 (IVS 6 ) A>T and c.1234 (exon 13 ) C>T in DDC gene is often severe and has early onset.

Key words: aromatic L-amino acid decarboxylase deficiency; DDC gene; compound heterozygous variation