Among the rare diseases, Huntington’s chorea is one of the most common. It is a progressive neurodegenerative disease that causes serious consequences such as the onset of involuntary movements, dementia, personality changes and psychiatric involvement.
Facts about Huntington’s chorea
Huntington’s chorea is a disease caused by the alteration of the huntingtin gene located on chromosome 4 of the DNA. It has an autosomal dominant inheritance pattern, i.e. the descendants of an affected person have a 50% chance of inheriting the disease. In case of receiving it genetically, it is certain that they will develop it during their lifetime.
Appearance of the first symptoms and treatment
Its manifestation usually appears between 30 and 50 years of age and its development has a fatal end after 15 to 20 years of progressive physical and mental incapacitation of the disease.
Currently there is no cure, but there is the possibility of preventing its transmission to children thanks to the Preimplantational Genetic Diagnosis (PGD) method of Assisted Reproduction. By means of this diagnosis, the embryos, previously obtained by In Vitro Fertilization (IVF), are studied to select those that are free of the disease. The embryos that show normal results after the analysis are transferred to the mother’s uterus. This is a solution for those who suffer from the disease or who suspect that they may carry it, but who do not renounce the possibility of having healthy children.
Parental testing
If a person suspects that he or she is a carrier of Huntington’s chorea, different protocols are offered, depending on whether or not they wish to know if they are carriers of the genetic alteration.
In the case of those patients who wish to know if they have the gene alteration, although at that moment they do not present any symptoms of the disease, tests for the affected gene are performed, both on them and on the embryos obtained through IVF. However, on other occasions, the patient does not wish to know if he/she is a carrier, but wants the embryos to be tested and to avoid having children affected by this pathology. In the latter case, which is the most common, we can proceed in two ways:
- We perform the tests on both the parent and the embryos, but the results are not communicated to the parent, thus remaining under the custody of the center.
- Indirect” method. This procedure is the most recommended in the case of parents with relatives affected by Huntington’s chorea and who do not wish to know their genetic situation. The person at risk does not undergo the study to find out if he/she has the altered gene, so no one will know if he/she will suffer from this disease in the future. The couple undergoes IVF treatment combined with “exclusion” PGD. The embryos are analyzed indirectly, so that only those that have not inherited the chromosomal region of the diseased relative are chosen. The advantage of this option is that the patient does not know if he/she is a carrier of the disease, which does not condition his/her life”.