Molecular cytogenetic characterization of ring chromosome 4 in a female having a chromosomally normal child.

We present the clinical and molecular findings of mosaic ring chromosome 4. The patient was referred to us for infertility and short stature. Results of three repeated cytogenetic analyses from lymphocytes showed a similar mosaic karyotype with multiple cell-lines [46,XX,r(4)/45,XX,-4/46,XX,dic r(4)/47,XX,r(4),+r(4)/46,XX]. FISH showed deletion of the 4p subtelomeric region and the 4q telomeric region from the ring chromosome 4. The breakpoints were mapped using molecular analysis. Parental karyotypes were normal. During the course of this study, the patient became pregnant without assisted reproductive technology. The result of amniocentesis performed at 16 weeks gestation showed a normal karyotype. Delivery was uncomplicated. This is the first report, to our knowledge, of the presence of ring chromosome 4 having various mosaic conditions in a female having a chromosomally normal fetus.