%0 Case Reports
%T Hypertryptophanemia due to tryptophan 2,3-dioxygenase deficiency.
%A Ferreira P
%A Shin I
%A Sosova I
%A Dornevil K
%A Jain S
%A Dewey D
%A Liu F
%A Liu A
%J Mol Genet Metab
%V 120
%N 4
%D 04 2017
%M 28285122
%F 4.204
%R 10.1016/j.ymgme.2017.02.009
%X In this report we describe the first human case of hypertryptophanemia confirmed to be due to tryptophan 2,3-dioxygenase deficiency. The underlying etiology was established by sequencing the TDO2 gene, in which there was compound heterozygosity for two rare variants: c.324G>C, p.Met108Ile and c.491dup, p.Ile165Aspfs*12. The pathogenicity of these variants was confirmed by molecular-level studies, which showed that c.491dup does not produce soluble protein and c.324G>C results in a catalytically less efficient Met108Ile enzyme that is prone to proteolytic degradation. The biochemical phenotype of hypertryptophanemia and hyperserotoninemia does not appear to have significant clinical consequences.