Wiederholtes vorkommen der lateralitätssequenz innerhalb einer familie mit abweichender expressivität

Background. Laterality sequences are abnormalities in the development of normal body asymmetry. In addition to reversal of sides with partial or complete situs inversus, bilateral left-sidedness or right-sidedness can occur. In the case of bilateral left-sidedness called situs ambiguus it is usually associated with polysplenia. Bilateral right-sidedness mostly presents with asplenia. The asplenic form is characterized of complex severe cardiac anomalies. The Ivemark syndrome, or polyasplenia syndrome is the association of situs ambiguus and cardiac malformations. Case report. We describe two siblings with laterality sequences of different phenotypic expressivity. The elder brother has had a situs inversus totalis. His younger brother, who died at the age of eleven days was diagnosed with Ivemark-syndrome and polysplenia. The occurence of these two forms of laterality sequences in one family is rare. Intrauterine diagnosis. Intrauterine diagnosis based on molecular genetic methods is not yet available in this syndrome. The fetal echocardiography at 18.-20. weeks of gestation is an effective method of early prenatal detection.