Late onset ornithine transcarbamylase deficiency in a 61 year old male

Thomas Malfait, Gert De Schoenmakere, Filip Gallant, Hans Schepkens, Ann Van Loo, Wouter Meersseman, David Cassiman, Steven Brabant, Johannes Häberle, Wim Terryn


Ornithine transcarbamylase (OTC) deficiency is the most frequent innate urea cycle disorder (UCD) and is the only one with an X-linked inheritance. OTC deficiency leads to hyperammonemia and subsequent elevated cerebral pressure and brain damage. Most often, UCDs are described as acute onset hyperammonemia in the newborn; however, rare, it can present in adulthood. We present the case of a 61-year old Caucasian man with unexplained coma. He developed an acute hyperammonemic encephalopathy leading to mental problems, seizures and coma. Despite the classical treatment with hemodialysis and the administration of a combination of sodium phenylacetate and sodium benzoate, the patient unfortunately died of cerebral herniation. Postmortem, genetic analysis confirmed the presence of a c.662G > A (p.Ala208Thr) pathogenic mutation in the OTC gene in a hemizygous state.  Synopsis: The association of neuropsychiatric symptoms or encephalopathy of unknown origin should lead, even in the absence of liver disease and even in late adulthood, to a high level of suspicion of hyperammonemia secondary to UCDs to ensure a timely diagnosis and life-saving treatment. UCD, an inborn error of metabolism, can present itself at an advanced age; attenuated phenotypes probably remain under-ascertained.

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Case Reports in Internal Medicine

ISSN 2332-7243(Print)  ISSN 2332-7251(Online)

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