Prenatal Screening – Huntington's Victoria

Prenatal Diagnosis is a crucial process involving testing a baby in the pregnant uterus to determine if it has inherited Huntington’s disease (HD). This two-step journey begins with to-be-parents, at least one of whom has a definitive HD diagnosis, being referred to a fetal medicine centre. Here, they engage in a detailed conversation with a genetic counsellor, exploring the pros and cons of testing an unborn fetus for an adult-onset, unpredictable neurological disorder.

Should the parents decide to proceed with prenatal testing, the mother undergoes one of the following procedures following a natural conception:

CVS (Chorionic Villus Sampling):

Typically performed between 10-13 weeks of pregnancy, CVS involves removing a piece of the developing placenta through a woman’s abdomen, using a catheter or needle as the ultrasound probe guides the process. As this tissue is 99 percent genetically identical to the fetus, DNA testing can determine the HD status, providing a conclusive result.

Huntingtons-Victoria-Chorionic Villus-Sampling

Figure 1: CVS (Chorionic Villus Sampling)

Amniocentesis

Conducted between 15-20 weeks of pregnancy, amniocentesis involves the removal of a small amount of amniotic fluid surrounding the baby using a thin needle, as the ultrasound probe guides the process. Cells from the baby in this fluid can be isolated, grown in the lab, and tested for HD status.

Figure 2: Amniocentesis

Regardless of the sample extraction method, genetic testing is performed on the fetal sample to determine the CAG repeat numbers. Despite the initial apprehension, prenatal testing has empowered thousands of families facing hereditary rare diseases, offering them the ability to make informed decisions and take control of their reproductive choices.