Unexplained death in patients with NGLY1 mutations may be explained by adrenal insufficiency

Homozygous mutations in NGLY1 were recently found to cause a condition characterized by a complex neurological syndrome, hypo‐ or alacrimia, and elevated liver transaminases. For yet unknown reasons, mortality is increased in patients with this condition. NGLY1 encodes the cytosolic enzyme N‐glycanase 1, which is responsible for the deglycosylation of misfolded N‐glycosylated proteins. Disruption of this process is hypothesized to lead to an accumulation of misfolded proteins in the cytosol. Here, we describe the disease course of a girl with a homozygous mutation in NGLY1, namely c.1837del (p.Gln613 fs). In addition to the previously described symptoms, at the age of 8 she presented with recurrent infections and hyperpigmentation, and, subsequently, a diagnosis of primary adrenal insufficiency was made. There are no previous reports describing adrenal insufficiency in such patients. We postulate that patients with NGLY1 deficiency may develop adrenal insufficiency as a consequence of impaired proteostasis, and the accompanying proteotoxic stress‐induced cell death, through defective Nrf1 function. We recommend an annual evaluation of adrenal function in all patients with NGLY1 mutations in order to prevent unnecessary deaths.