Pattern of chromosomal inversions identified by a birth defects registry, Hawaii, 1986-2002.

The aim of the investigation was to describe chromosomal inversions identified by a birth defects registry with respect to chromosomes involved, pregnancy outcome, method of diagnosis, inheritance, sex and diagnosis of major structural birth defects. Cases were derived from a population-based birth defects registry in Hawaii and comprised all infants and fetuses with chromosomal deletions delivered during 1986-2002. A total of 68 cases were identified through a statewide birth defects registry in Hawaii during 1986-2002. The chromosomes involved in the greatest proportion of inversions were chromosomes 6 (18%) and 9 (18%). Live births accounted for 62 (91%) of the cases. Diagnosis was made by amniocentesis or chorionic villus sampling in 60 (88%) of the cases. Of the 43 cases with known inheritance, the inversion was inherited in 40 (93%) and de novo in three (7%). Males accounted for 31 (46%) and females for 37 (54%) of the cases. Major structural birth defects were identified in 12 (18%) of the cases. Inversions diagnosed among infants and fetuses in Hawaii do not appear to affect all chromosomes equally. Most detected inversions occurred among live births and were inherited conditions. Infants and fetuses with inversions are not frequently associated with major structural birth defects.