Hyperferritinemia cataract syndrome ... (Hyperferritinemia-cataract syndrome) - Gen FTL.
Hereditary cataractous hyperferritinemia syndrome (SHHC) is a disorder characterized by an excess of ferritin in the blood (hyperferritinemia) and body tissues. Clinical suspicion may arise to individuals with early cataracts, especially if they are family, and people with high levels of ferritin unexplained and no signs of iron overload.
This disease is due to mutations in the FTL gene, located on the long arm of chromosome 19 (19q13.33). This gene is involved in encoding the light chains of ferritin, which constitute a subunit ferritin. This region is called IRE (Iron Responsive Element: iron response element) and has the function of binding to cytoplasmic proteins IRP (Iron Regulatory Proteins: iron regulatory proteins). In case of iron deficiency, IRP proteins acquire a high affinity for the IRE and act by inhibiting the synthesis of ferritin light chains. IRE-IRP interaction occurs on a ring structure consisting of five pairs in one end of the IRE. Thus, mutations that alter the morphology of this structure reduced or canceled the ability to regulate the synthesis of ferritin light chains, to stop operating the negative feedback system responsible for regulation. Therefore ferritin it is synthesized in excess resulting in the formation of complexes that accumulate, leading to increased concentrations of serum ferritin, liver, lymphoid cells and lens, causing early onset cataracts.
So far they described at least 31 FTL gene mutations associated with this syndrome, most of them caused by nucleotide changes and sometimes due to some various deletions. In principle, as the mutation is closest to the annular region of the IRE, earlier and more severe alteration will find that this cause.
This disease is inherited as an autosomal dominant, which means that a copy of the altered gene in each cell is sufficient for the disease to be expressed. In most cases, an affected person has a parent with the disease.
Tests in IVAMI: in IVAMI perform detection of mutations associated with cataract hyperferritinemia (SHHC) syndrome by complete PCR amplification of exons FTL gene, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).