In communities with high consanguinity within families genetic diseases. The best example is a country which has the highest incidence of hereditary diseases in the world. There the hemophilia, Gaucher's disease and some forms of Fanconi's Anemia (Fanco Fanco-C and-G) are serious health problems.

In societies, the very high costs involved in in vitro fertilization and the completion of SNP-PCR for the detection of these diseases create prohibitive costs, the qe limit its application to a few families, with a possible and important exception: sickle cell anemia, which is the most important genetic disease in the population.

Mutations of BCRA1 and BCRA2 cause only 10% of breast cancer. If they were responsible for 100% not be necessary to create an individual in vitro and only implement it in a uterus is negative.

What is recommended in these families is the prophylactic Mastectomy. The patients with mutations and family history are subject to bilateral mastectomy with preservation of skin and subcutaneous tissue and subsequent implantation of silicone prostheses.

The examination does not assess all the chromosomes and genes, but detects the anomalies of major diseases. The main are of chromosome 13 (Patau syndrome), chromosome 18 (Edwards syndrome), chromosome 21 (Down Syndrome) and sex chromosomes X and Y (Hemophilia, Turnner and others). In other countries may also be assessed the chromosomes 14, 15, 16, 17 and 22. In special cases can be evaluated genetic diseases such as cystic fibrosis, Huntington's disease, Tay Sachs, Korea and others.

French and American scientists mapped the chromosome 14, the longest sequence known until now harbors genes of more than 60 diseases, including a recently linked to early development of Alzheimer's disease. The work brought together nearly one hundred researchers in an international effort.

According to scientists, national center for genetic sequencing, chromosome 14 is formed by more than 87 million pairs of DNA.

All were sequenced, which means that the map of chromosome is complete, without gaps. 'Until now, is the largest continuous piece of DNA sequenced.