Hoyeraal-Hreidarsson syndrome/Dyskeratosis congenita

Defects in DKC1 are a cause of X-linked dyskeratosis congenita (DKC) and Hoyeraal-Hreidarsson syndrome (HHS). DKC is a disease characterized by the early manifestation of reticulate skin pigmentation, nail dystrophy, and mucosal leukoplakia. Progressive bone marrow failure occurs in over 80% of cases and is the main cause of early mortality. Hoyeraal-Hreidarsson syndrome is a multisystem disorder affecting males and is characterized by aplastic anemia, immunodeficiency, microcephaly, cerebellar hypoplasia, and growth retardation. HHS is a severe variant of dyskeratosis congenita.

Alternative names


Cerebellar hypoplasia with pancytopenia

Growth retardation, prenatal, with progressive pancytopenia and cerebellar hypoplasia


  • Defects of phagocyte function




#300240 Hoyeraal-Hreidarsson; HHS

#305000 Dyskeratosis congenita, X-linked; DKC

*300126 Dyskerin; DKC1

Cross references

Phenotypically related immunodeficiencies



Incidence is not known.