**1. Introduction**

## **1.1 Updates in diagnosis**

#### *1.1.1 Preimplantation genetic diagnosis*

Prenatal diagnosis (PND) services are the best practices to control prevalence of disease. Wide spread practicing of PND proved effective in reducing the number of new cases but on the other hand high abortion rate is hided, which ethically unaccepted and for many couples is not a suitable choice. Preimplantation genetic diagnosis is considered in a similar fashion to prenatal diagnosis (PGD) and is a strong alternative to conventional PND. PGD means genetic profiling of embryos prior to implantation (embryo profiling). Its main advantage is that it avoids selective pregnancy termination as the method makes it highly likely that the baby will be free of the disease under consideration. At present PGD is the only abortion free fetal diagnostic process [1].

**The most important indications of PGD [1] are:**

