Severe Disseminated Phaeohyphomycosis in a Patient with Inherited CARD9 Deficiency

The caspase recruitment domain containing protein 9 (CARD9) deficiency is a primary immunodeficiency disorder that affects the innate immune system, resulting in increased susceptibility to fungal infections. We describe progressive disseminated phaeohyphomycosis due to a melanized fungus in a 26-year-old healthy female with inherited CARD9 deficiency to highlight the clinical presentation of this disorder.

The diagnosis of disseminated phaeohyphomycosis due to melanized fungi was made on the basis of clinical and histopathological findings. CARD9 gene was sequenced and a homozygous c.883C>T mutation in exon 6 at codon 295 was found, resulting in a mutation at position 295, Q295X.

There are more cases of fungal infection associated with CARD9 deficiency in Iran compared to other Asian countries. Although consanguineous marriage is common in the Middle East, severe fungal infections related to CARD9 deficiency were only reported from Iran and Turkey. The higher incidence in comparison to other Middle Eastern countries may be associated with rapid population growth, large family size, and the availability of diagnostic facilities. Although Iranian patients with Q295X mutation are susceptible to candidiasis and dermatophytosis, our patient is the first report of phaeohyphomycosis related to Q295 mutation.