Simultaneous presentation of hereditary hyperferritinaemia cataract syndrome and hereditary haemochromatosis

Hereditary hyperferritinaemia cataract syndrome (HHCS; OMIM 600886) is a rare autosomal dominant disorder characterized by early cataract formation and isolated high serum ferritin. Typical cataracts in HHCS are of a distinctive morphology characterized by progressive axial and peripheral white flecks with small crystalline aggregates.1 HHCS is caused by variants in the iron‐responsive element (IRE) of the ferritin light chain (FTL) gene (OMIM 134790), which disrupt binding of the inhibitory iron‐regulation protein to the IRE loop, leading to excessive dysregulated serum ferritin production. Ferritin is a large iron cellular storage protein, and accumulation in the lens fibres is suspected to be responsible for the aetiology of cataract formation in HHCS. HHCS often presents by the second decade of life and has a minimum prevalence of approximately 1 of 200 000, although this is likely an underestimate.1 HHCS is often biochemically mistaken for haemochromatosis, as hyperferritinaemia can suggest iron overload.2