Asparagine-linked glycosylation 13 homolog (ALG13) encodes a nonredundant, highly conserved, X-linked uridine diphosphate (UDP)-Nacetylglucosaminyltransferase required for the synthesis of lipid linked oligosaccharide precursor and proper N-linked glycosylation. De novo variants in ALG13 underlie a form of early infantile epileptic encephalopathy known as EIEE36, but given its essential role in glycosylation, it is also considered a congenital disorder of glycosylation (CDG), ALG13-CDG. Twenty-four previously reported ALG13-CDG cases had de novo variants, but surprisingly, unlike most forms of CDG, ALG13-CDG did not show the anticipated glycosylation defects, typically detected by altered transferrin glycosylation. Structural homology modeling of two recurrent de novo variants, p.A81T and p.N107S, suggests both are likely to impact the function of ALG13. Using a corresponding ALG13-deficient yeast strain, we show that expressing yeast ALG13 with either of the highly conserved hotspot variants rescues the observed growth defect, but not its glycosylation abnormality. We

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Antibody-mediated encephalopathies associated with serum or cerebrospinal fluid antibodies directed against neuronal structures may present with a multitude of neuropsychiatric syndromes. Although some of the antibody-driven conditions are now well recognized in adults (eg, N-methyl-D-aspartate receptor antibody encephalitis), the spectrum of neuropsychiatric manifestations in the pediatric population is less clear. Psychosis, confusion, catatonia, and additional behavioral changes, along with seizures, encephalopathy, and movement disorders, may be initial manifestations or concurrent features in all age groups. Psychosis, when present, is often part of a broader spectrum of neurological and neuropsychiatric symptoms for which the diagnosis of autoimmune encephalitis is considered. The authors present the case of an adolescent with an acute and isolated psychotic presentation of voltage-gated potassium channel antibody encephalitis, further expanding the phenotypic spectrum of this specific antibody-mediated disease and raising the possibility that specific immune-mediated processes may define a biological subgroup of psychoses.