[Preimplantaion genetic diagnosis of hearing loss with 35delG mutation in GJB2 gene - preliminary report].

35delG mutation in GJB2 gene is the most frequent mutation in genetic hearing loss. The carrier screening for 35delG mutation to identify affected newborns is at the moment relatively inexpensive method for deafness diagnosis. The casual treatment of DFNB1 is impossible. Preimplantation genetic diagnosis (PGD) is a method allowing transfer mutation free embryos and successful pregnancies. It's an established procedure allowing genetic research of the oocyte before fertilization or embryo before implantation to the uterus. Aim: The aim of the present work was to perform PGD for GJB2 35delG mutation in a couple who had already a child affected with genetic hearing loss.
The patient underwent a standard IVF procedure associated with intracytoplasmic sperm injection. 6–8 cell embryos were biopsied on day 3. Single cell nested PCR-RFLP protocol and sequence analysis for PGD was used for the detection of GJB2 35delG mutation.
In the course of IVF-PGD procedures, from 6 analyzed embryos 3 were predicted to be free of GJB2 35delG mutation in both alleles. Two embryos were heterozygous and one was affected for this mutation as homozygous mutation in both alleles. Of these, one healthy embryo was transferred, resulting in an unaffected singleton pregnancy.
Preimplantation genetic diagnosis (PGD) of monogenic disorders is a very efficient method, especially for patients whose previous child is homozygous for genetic disorders. It offers new possibilities for the treatment for genetic disease carriers.