Introduction: Porphyrias constitute a collection of hereditary metabolic disorders
arising from disturbances in the enzymatic activities inherent to the heme
biosynthetic pathway. Eight subtypes of porphyria, each associated with enzymes in
the heme biosynthesis pathway, have been identified. Hereditary coproporphyria is
one of the porphyria subtypes characterized by neuropsychiatric clinical features. It
develops as a result of a deficiency in coproporphyrinogen oxidase enzyme activity.
Consequently, an accumulation of coproporphyrin and its precursor metabolites
is observed. Hereditary coproporphyria exhibits autosomal dominant inheritance.
Following clinical suspicion, a diagnosis is made with biochemical and genetic tests.
The presence of nonspecific symptoms and the lack of consideration for porphyria
in differential diagnosis complicate the diagnosis.
Case: An 18-year-old male patient was referred to our psychiatry clinic only with
psychiatric complaints. The mental status examination revealed affective signs,
along with visual hallucinations and delusions. Blood tests and cranial scans at
admission showed no abnormalities. After initiating treatment with valproic acid and
olanzapine for a presumptive diagnosis of bipolar I disorder, a manic episode with
psychotic features, the patient’s general medical condition worsened. During clinical
observation, the appearance of neurological and gastrointestinal system findings
led to a reconsideration of the diagnosis, and porphyria was considered. Urine tests
revealed elevated levels of porphyrin intermediates. The diagnosis of hereditary
coproporphyria was confirmed by genetic testing, which identified the c.734 C>T
mutation in the coproporphyrinogen oxidase gene. Symptomatic relief was observed
following a carbohydrate-rich diet without the need for psychotropic treatment.
Conclusion: Although their subtypes exhibit distinct clinical features, porphyrias
typically present with involvement of multiple systems. Cases that initially present
with symptoms specific to a single system can pose diagnostic challenges. In our
case report, we aimed to present the psychiatric onset of hereditary coproporphyria,
a rare subtype of porphyria known for its potentially fatal attacks when untreated.
Keywords: Case report, coproporphyrinogen oxidase, hereditary coproporphyria,
porphyrias