Two cases of familial paracentric inversion in man associated with sex chromosome anomaly

Abstract

A paracentric inversion of chromosome 5 was detected after RHG banding in a subject affected by Klinefelter's syndrome. The inversion was also observed in the patient's mother, and was confirmed by QFQ-and RBA-banding techniques. A second paracentric inversion affecting chromosome 7 was detected in a woman with Turner's syndrome. The same structural anomaly was found in her father and her half-brother. The possible relationship between sex chromosome nondisjunction and paracentric inversion is discussed. Furthermore, the inversion of chromosome 7 reproduces exactly the chromosome 7 of the gorilla, which is presumed to be ancestral to the human 7. This therefore appears to be the first reported case of reverse chromosomal mutation.