Diagnóstico molecular del gen HFE de la hemocromatosis hereditaria

Abstract

Hereditary hemochromatosis (HH), also known as iron overload disease, is an inherited disorder in which ironaccumulates in blood (because too much is absorbed by the intestines), liver, heart, pancreas, pituitary gland,joints and other tissues. HH is most often caused by a faulty gene on chromosome 6 named HFE. Most of affectedindividuals have two copies of the Cys282Tyr mutation of the HFE gene while only a low percentage ofindividuals have either one or two copies of the second mutation, which is called His6Asp.The individuals havingtwo copies of His63Asp mutation and those having a only copy of any of both mutations have not more risk forhemochromatosis than that the normal people. One of each 9 people is carrier of some of these mutations: theyhave a copy of the normal gene and another one of the mutation. The people with the disease have received amutant copy of each one of their two parents who, frequently, are individual carriers of the mutation which theydo not display hemochromatosis. In spite of the high incidence of this disease (0.3%), most of the cases remainwithout diagnose. Luckily, HH is between the few diseases that with an earlier diagnosis have a simple andeffective treatment. Under treatment, the life expectancy of the patient is normal.The HH DNA test for screening of the general population lead to an unequivocal detection of either the carryingpeople having a copy of the mutation (with risk of having children with the disease) or the people with twocopies of the mutation (those that displays the disease or that will with a highest probability develop it in thefuture).Primary objectives in HH diagnosis are: to examine HFE mutations and to increase individual information ongenetic risk. Genetic advice should be carried out to the patient and their family on the inheritance form, theimplications of the disease and the genetic risk. Genealogical familiar history, genetic tree and genetic testshould be realised to clarify the family situation.