Genetic disease may be diagnosed in the prenatal period by karyotype analysis, in case of aneuploidies, or by DNA analysis, in case of other diseases.
The test is performed by removal of material containing cells of the embryo by amniocentesis (extraction of amniotic fluid) or cordocentesis (puncture of the umbilical cord) or even by chorionic villus biopsy (that can be done earlier in gestation).
Ultrasonography is a diagnostic procedure for some genetic diseases that produce morphological variations during the embryonic development. The study of genetic family trees is also an important auxiliary method in the early diagnosis of many genetic diseases.