[Research of gene(s) involved in situs inversus. Initial results].

Reverse Genetics consists in identifying the gene responsible for a hereditary condition, the biochemical mechanism of which is unknown. We have applied this approach to families recruited according to the following criteria: 1) at least two members of the family must be affected; 2) one of the two subjects must have an abnormality of thoracic and/or abdominal lateralization. This abnormality of situs can form part of a syndrome: asplesia, polysplenia, heterotaxia, dextrocardia, situs inversus, Kartagener' or Ivemark's syndrome; 3) the other affected subject(s) must have some form of congenital heart disease and/or one of the phenotypes above described in 2); 4) in consanguinous marriages, only one child fulfilling the criteria in 2) above described is required. Eight families conforming to the above criteria are presented; lymphocytic transformation was successful in 90% of cases when the blood sample was received within 48 hours. The segregation of the alleles is in favour of a linkage between the tested probe and the syndrome(s) studied. In order to identify the gene responsible, we will have to increase the number of families studied and extend our research to sporadic cases.